Forest-like Laser-Induced Graphene Film with Ultrahigh Solar Energy Utilization Efficiency

Femtosecond Laser Opening Hierarchical Lamination: Micro-Nano Hybrid Scissoring of Three-Dimensional Nitrogen-Doped Graphene for Solar Steam Generation

Three-dimensional (3D) nanoporous nitrogen-doped graphene is an ideal candidate for solar steam generation. However, the outermost dense layer formed during high-temperature thermal chemical vapor deposition (CVD) severely blocks water transport and steam escape. In this work, a technique of femtosecond laser opening hierarchical lamination (FLOHL) enabling hierarchical micro-nano hybrid scissoring of graphene is presented for its structural and performance upgrades. FLOHL not only allows noncontact rapidly hierarchical opening of the blocked layer but also enables opening lamination of close thin-wall graphene into suspended sheets, while maintaining a robust connection with the framework facilitating stable repetitive use for water evaporation. After FLOHL, solar absorption, heat localization, and interfacial wetting are all dramatically enhanced, increasing water evaporation rates from 1.58/1.56 to 1.79/1.77 kg m-2 h-1 for two prototypes under 1 sun irradiation and conversion efficiency from ∼80% to ∼90%, making them better than many solar evaporators built with graphene and its derivatives, including laser-induced graphene.

Laser processing materials for photo-to-thermal applications

Photothermal conversion materials (PCMs) are crucial component in solar-thermal energy technologies. Although various PCMs with excellent sunlight harvesting have been developed for colorful solar-thermal applications, uniform and large-scale production of PCMs remains a challenge, and the PCMs prepared through the conventional methods are often non-site specific. Laser processing technology (LPT), as an efficient, convenient, green and sustainable technology, can directly create micro/nano structures and patterns at specific locations on materials surface, attracting widespread attention in photo-to-thermal applications. Here, we summarize the laser processing of preparing PCMs through laser sintering, laser modification, laser ablation in liquid, laser induced carbonization, and laser etching. We also introduce the working mechanism of LPT, and analyze the thermal conductivity, heat storage performance and hydrophilic/hydrophobic properties of the substrate after LPT treatment. Furthermore, the application of LPT in solar anti-icing/deicing, seawater desalination, heat exchange system, energy storage and transfer, and other related fields are introduced. Additionally, we provide a prospect for the development of LPT and offer directions for future research. We hope that this review can provide meaningful reference value for scholars in this field.

Dual-Sided Superhydrophobic Laser-Induced Graphene Evaporator for Efficient Desalination and Brine Treatment under High Salinity

The immense energy footprint of desalination and brine treatment is a barrier to a green economy. Interfacial evaporation (IE) offers a sustainable approach to water purification by efficient energy conversion. However, conventional evaporators are susceptible to fluctuations in solar radiation and the salinity of handling liquid. The present research is an innovative step toward the fabrication of superhydrophobic laser-induced graphene (LIG) interfacial evaporators for desalination and brine treatment. The fabricated dual-sided superhydrophobic laser-induced graphene (DSLIG) exhibits self-cleaning ability on both sides, enhancing salt rejection capabilities through a lotus effect. This multilayered evaporator comprises a top layer of MPES LIG and a bottom layer of PVDF AR 972 LIG, resulting in superior localized heat generation ability. The engineered surface has undergone performance analysis with DI water and NaCl solutions with concentrations of 3.5-24 wt %. The dual-stacked configuration with coupled solar (one sun)-joule heating (5 V) attained evaporation rates of ∼5 kg m-2 h-1 for distilled water and ∼2.2 kg m-2 h-1 for a 24 wt % NaCl solution. The remarkable outcome resulted from substantial thermophysical property changes with LIG formation. The DSLIG's bottom concentration gradient promoted salt back diffusion and ceased salt penetration to the top surface. The work can be further extended to treat the desalination brine for sustainable desalination and zero liquid discharge.

Biomimetic Micro-Nanostructured Evaporator with Dual-Transition-Metal MXene for Efficient Solar Steam Generation and Multifunctional Salt Harvesting

Solar-driven interfacial evaporation is one of the most attractive approaches to addressing the global freshwater shortage. However, achieving an integrated high evaporation rate, salt harvesting, and multifunctionality in evaporator is still a crucial challenge. Here, a novel composite membrane with biomimetic micro-nanostructured superhydrophobic surface is designed via ultrafast laser etching technology. Attractively, the double-transition-metal (V1/2Mo1/2)2CTx MXene nanomaterials as a photothermal layer, exhibiting the enhanced photothermal conversion performance due to elevated joint densities of states, which enables high populations of photoexcited carrier relaxation and heat release, provides a new insight into the photothermal conversion mechanism for multiple principal element MXene. Hence, the (V1/2Mo1/2)2CTx MXene-200 composite membrane can achieve a high evaporation rate of 2.23 kg m-2 h-1 under one sun, owing to the enhanced "light trap" effect, photothermal conversion, and high-throughput water transfer. Synergetically, the membrane can induce the directed precipitation of salt at the membrane edge, thus enabling salt harvesting for recycling and zero-emission of brine water. Moreover, the composite membrane is endowed with excellent multifunctionality of anti-/de-icing, anti-fouling, and antibacterial, overcoming the disadvantage that versatility is difficult to be compatible. Therefore, the evaporator and the promising strategy hold great potential for the practical application of solar evaporation.

Hierarchically Porous Polypyrrole Foams Contained Ordered Polypyrrole Nanowire Arrays for Multifunctional Electromagnetic Interference Shielding and Dynamic Infrared Stealth

As modern communication and detection technologies advance at a swift pace, multifunctional electromagnetic interference (EMI) shielding materials with active/positive infrared stealth, hydrophobicity, and electric-thermal conversion ability have received extensive attention. Meeting the aforesaid requirements simultaneously remains a huge challenge. In this research, the melamine foam (MF)/polypyrrole (PPy) nanowire arrays (MF@PPy) were fabricated via one-step electrochemical polymerization. The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays. Due to the upwardly grown PPy nanowire arrays, the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00° and outstanding stability under various harsh environments. Meanwhile, the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays. Furthermore, taking advantage of the high conductivity (128.2 S m-1), the MF@PPy foam exhibited rapid Joule heating under 3 V, resulting in dynamic infrared stealth and thermal camouflage effects. More importantly, the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm2 g-1. Strong EMI shielding was put down to the hierarchically porous PPy structure, which offered outstanding impedance matching, conduction loss, and multiple attenuations. This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays, showing great applications in both military and civilian fields.

2D Materials for Potable Water Application: Basic Nanoarchitectonics and Recent Progresses

Water polluted by toxic chemicals due to waste from chemical/pharmaceuticals and harmful microbes such as E. Coli bacteria causes several fatal diseases; and therefore, water filtration is crucial for accessing clean and safe water necessary for good health. Conventional water filtration technologies include activated carbon filters, reverse osmosis, and ultrafiltration. However, they face several challenges, including high energy consumption, fouling, limited selectivity, inefficiencies in removing certain contaminants, dimensional control of pores, and structural/chemical changes at higher thermal conditions and upon prolonged usage of water filter. Recently, the advent of 2D materials such as graphene, BN, MoS2, MXenes, and so on opens new avenues for advanced water filtration systems. This review delves into the nanoarchitectonics of 2D materials for water filtration applications. The current state of water filtration technologies is explored, the inherent challenges they face are outlines, and the unique properties and advantages of 2D materials are highlighted. Furthermore, the scope of this review is discussed, which encompasses the synthesis, characterization, and application of various 2D materials in water filtration, providing insights into future research directions and potential industrial applications.

Recent innovations in 3D solar evaporators and their functionalities

Interfacial solar evaporation (ISE) has emerged as a promising technology to alleviate global water scarcity via energy-efficient purification of both wastewater and seawater. While ISE was originally identified and developed during studies of simple double-layered two-dimensional (2D) evaporators, observed limitations in evaporation rate and functionality soon led to the development of three-dimensional (3D) evaporators, which is now recognized as one of the most pivotal milestones in the research field. 3D evaporators significantly enhance the evaporation rates beyond the theoretical limits of 2D evaporators. Furthermore, 3D evaporators could have multifaceted functionalities originating from various functional evaporation surfaces and 3D structures. This review summarizes recent advances in 3D evaporators, focusing on rational design, fabrication and energy nexus of 3D evaporators, and the derivative functions for improving solar evaporation performance and exploring novel applications. Future research prospects are also proposed based on the in-depth understanding of the fundamental aspects of 3D evaporators and the requirements for practical applications.

Helical Micropillar Processed by One-Step 3D Printing for Solar Thermal Conversion

Solar thermal utilization has broad applications in a variety of fields. Currently, maximizing the photo-thermal conversion efficiency remains a research hotspot in this field. The exquisite plant structures in nature have greatly inspired human structural design across many domains. In this work, inspired by the photosynthesis of helical grass, a HM type solar absorber made in graphene-based composite sheets is used for solar thermal conversion. The unique design promoted more effective solar energy into thermal energy through multiple reflections and scattering of solar photons. Notably, the Helical Micropillar (HM) is fabricated using a one-step projection 3D printing process based on a special 3D helical beam. As a result, the solar absorber's absorbance value can reach 0.83 in the 400-2500 nm range, and the surface temperature increased by ≈128.3% relative to the original temperature. The temperature rise rate of the solar absorber reached 22.4 °C min-1, demonstrating the significant potential of the HM in practical applications of solar thermal energy collection and utilization.

Graphene Microflower by Photothermal Marangoni-Induced Fluid Instability for Omnidirectional Broadband Photothermal Conversion

2-D carbon-based materials are well-known for their broadband absorption properties for efficient solar energy conversion. However, their high reflectivity poses a challenge for achieving efficient omnidirectional light absorption. Inspired by the multilevel structures of the flower, a Graphene Microflower (GM) material with gradient refractive index surface was fabricated on polymer substrates using the UV-intense laser-induced phase explosion technique under the synergistic design of the photothermal Marangoni effect and the fluid instability principle. The refractive index gradient reduces light reflection and absorbs at least 96% of light at incident angles of 0-60° across the entire solar wavelength range (200-2500 nm). Over 90% absorption even at 75° angle of incidence. The light absorption is enhanced by the multiple interferometric phase cancelation and localized surface plasmon resonance, resulting in a steady-state temperature 60 °C higher than ambient conditions under one solar irradiation. The max rate of temperature rise can reach up to 62 °C s-1. The device is then integrated at the hot end of the temperature difference generator at high altitude to ensure continuous and efficient power generation, producing a steady-state power of 196 mW.

Robust and Flexible Rubber Composite with High Photothermal Properties Achieved by In Situ ZDMA Assisted Dispersion of Eumelanin and its Hydrophobic Photothermal Application

Eumelanin, a natural, biocompatible, and biodegradable photothermal agent derived from biomass, has attracted increasingly considerable attention due to its outstanding photothermal conversion efficiency. Unfortunately, its tendency to aggregate in flexible non-polar polymers, owing to its abundant polar groups on the surface, severely restricted the application of eumelanin in photothermal composite field. Herein, a feasible strategy is proposed to disperse eumelanin in non-polar rubber matrix via in situ generation of Zinc dimethacrylate (ZDMA). The graft-polymerization of ZDMA promotes the interfacial compatibility between styrene butadiene rubber (SBR) and eumelanin, achieving a uniform dispersion of eumelanin in SBR. The rubber composite exhibits a considerable tensile strength of 11.4 MPa, acceptable elongation at break of 146%, and outstanding photothermal conversion efficiency of up to 75.2% with only 1 wt% of eumelanin. Furthermore, based on the easy-processing of SBR matrix, the composite is treated with a sandpaper template technique and sprayed with trimethoxy(1H,1H,2H,2H-perfluorodecyl)silane (PFDTMS) to endow the material with near superhydrophobicity (water contact angle of 147.9°) capacity. Hydrophobicity provides excellent icing resistance, with droplet surfaces extending more than twice as long to freeze. Moreover, this hydrophobic photothermal material exhibits remarkable anti-frosting, de-frosting, and de-icing capabilities.

Photothermal Conversion Porous Organic Polymers: Design, Synthesis, and Applications

Solar energy is a primary form of renewable energy, and photothermal conversion is a direct conversion process with tunable conversion efficiency. Among various kinds of photothermal conversion materials, porous organic polymers (POP) are widely investigated owing to their controllable molecular design, tailored porous structures, good absorption of solar light, and low thermal conductivity. A variety of POP, such as conjugated microporous polymers (CMP), covalent organic frameworks (COF), hyper-crosslinked porous polymers (HCP), polymers of intrinsic microporosity (PIM), porous ionic polymers (PIP), are developed and applied in photothermal conversion applications of seawater desalination, latent energy storage, and biomedical fields. In this review, a comprehensive overview of the recent advances in POP for photothermal conversion is provided. The micro molecular structure characteristics and macro morphology of POP are designed for applications such as seawater desalination, latent heat energy storage, phototherapy and photodynamic therapy, and drug delivery. Besides, a probe into the underlying mechanism of structural design for constructing POP with excellent photothermal conversion performance is methodicalized. Finally, the remaining challenges and prospective opportunities for the future development of POP for solar energy-driven photothermal conversion applications are elucidated.

Ruthenium Anchored Laser-Induced Graphene as Binder-Free and Free-Standing Electrode for Selective Electrosynthesis of Ammonia from Nitrate

Developing effective electrocatalysts for the nitrate reduction reaction (NO3RR) is a promising alternative to conventional industrial ammonia (NH3) synthesis. Herein, starting from a flexible laser-induced graphene (LIG) film with hierarchical and interconnected macroporous architecture, a binder-free and free-standing Ru-modified LIG electrode (Ru-LIG) is fabricated for electrocatalytic NO3RR via a facile electrodeposition method. The relationship between the laser-scribing parameters and the NO3RR performance of Ru-LIG electrodes is studied in-depth. At -0.59 VRHE, the Ru-LIG electrode exhibited the optimal and stable NO3RR performance (NH3 yield rate of 655.9 µg cm-2 h-1 with NH3 Faradaic efficiency of up to 93.7%) under a laser defocus setting of +2 mm and an applied laser power of 4.8 W, outperforming most of the reported NO3RR electrodes operated under similar conditions. The optimized laser-scribing parameters promoted the surface properties of LIG with increased graphitization degree and decreased charge-transfer resistance, leading to synergistically improved Ru electrodeposition with more exposed NO3RR active sites. This work not only provides a new insight to enhance the electrocatalytic NO3RR performance of LIG-based electrodes via the coordination with metal electrocatalysts as well as identification of the critical laser-scribing parameters but also will inspire the rational design of future advanced laser-induced electrocatalysts for NO3RR.

Development of a laser induced graphene (LIG) and polylactic acid (PLA) shape memory polymer composite with simultaneous multi-stimuli response and deformation self-sensing characteristics

This study presents the integration of laser-induced graphene (LIG) on a polylactic acid (PLA) substrate to create a novel shape memory polymer composite (SMPC) with multi-stimuli response and deformation self-sensing characteristics. The LIG was initially engraved on a commercial polyimide film and subsequently transferred to the PLA substrate through hot compression. Raman spectra analysis confirmed the successful engraving of the LIG, exhibiting the typical characteristic peaks. Durability tests revealed that the transferred LIG adhered well to the PLA substrate. Additionally, the transferred LIG demonstrated a sheet resistance of 40.3 Ω sq-1, which facilitated the electrical actuation of the LIG/PLA composite through Joule heating, allowing precise temperature control by manipulating the applied electrical power. An optimum electrical power of 0.95 W was identified to rapidly reach the actuation temperature without exceeding 80 °C. The study also demonstrated the LIG/PLA composite's responsiveness to infrared (IR) light, attributed to photothermal conversion behavior of LIG. An optimum IR intensity of 85 mW cm-2 was established for reaching the actuation temperature without surpassing 80 °C. This multi-stimulus functionality was achieved alongside real-time monitoring of the shape recovery ratio, enabled by the piezoresistive properties of LIG, which allowed for recording electrical resistance changes during recovery. This approach eliminates the need for external components and offers a straightforward fabrication process. The ability to actuate and sense deformation using a single, integrated LIG pattern opens new opportunities for developing advanced, multi-responsive, and self-sensing shape memory polymer composites.

Low vaporization enthalpy of modified chitosan hydrogel for high performance solar evaporator

The high vaporization enthalpy of water attributed to the strong hydrogen bonds between water molecules is limiting the performance of solar evaporators. This work demonstrates a deliberate attempt to significantly reduce the vaporization enthalpy of water through the introduction of weak water-amine hydrogen bond interactions in hydrogel evaporators. In this article, bio-based chitosan-agarose/multiwalled carbon nanotube hydrogel film evaporators (CAMFEs) exhibit larger vaporization enthalpy reduction with the presence of primary amine groups in chitosan. An interplay between vaporization enthalpy reduction and water diffusivity leads to an optimal ratio of chitosan to agarose = 7:1 (CAMFE7) showing an impressive evaporation rate of 4.13 kg m-2 h-1 under 1 sun irradiation. CAMFE7 also exhibits excellent salt resistance, with a stable water evaporation rate, using brine water of up to 10 % salinity under continuous 1 sun irradiation. The high mechanical robustness together with its scalability makes CAMFE7 a highly promising material for practical drinking water production.

Superhydrophobic Solar-to-Thermal Materials Toward Cutting-Edge Applications

Solar-to-thermal conversion is a direct and effective way to absorb sunlight for heat via the rational design and control of photothermal materials. However, when exposed to water-existed conditions, the conventional solar-to-thermal performance may experience severe degradation owing to the high specific heat capacity of water. To tackle with the challenge, the water-repellent function is introduced to construct superhydrophobic solar-to-thermal materials (SSTMs) for achieving stable heating, and even, for creating new application possibilities under water droplets, sweat, seawater, and ice environments. An in-depth review of cutting-edge research of SSTMs is given, focusing on synergetic functions, typical construction methods, and cutting-edge potentials based on water medium. Moreover, the current challenges and future prospects based on SSTMs are also carefully discussed.

Laser patterned graphene pressure sensor with adjustable sensitivity in an ultrawide response range

Flexible pressure sensors have attracted wide attention because of their applications in wearable electronic, human-computer interface, and healthcare. However, it is still a challenge to design a pressure sensor with adjustable sensitivity in an ultrawide response range to satisfy the requirements of different application scenarios. Here, a laser patterned graphene pressure sensor (LPGPS) is proposed with adjustable sensitivity in an ultrawide response range based on the pre-stretched kirigami structure. Due to the out-of-plane deformation of the pre-stretched kirigami structure, the sensitivity can be easily tuned by simply modifying the pre-stretched level. As a result, it exhibits a maximum sensitivity of 0.243 kPa-1, an ultrawide range up to 1600 kPa, a low detection limit (6 Pa), a short response time (42 ms), and excellent stability with high pressure of 1200 kPa over 500 cycles. Benefiting from its high sensitivity and ultrawide response range, the proposed sensor can be applied to detect physiological and kinematic signals under different pressure intensities. Additionally, taking advantage of laser programmable patterning, it can be easily configured into an array to determine the pressure distribution. Therefore, LPGPS with adjustable sensitivity in an ultrawide response range has potential application in wearable electronic devices.

Developing Salt-Rejecting Evaporators for Solar Desalination: A Critical Review

Solar desalination, a green, low-cost, and sustainable technology, offers a promising way to get clean water from seawater without relying on electricity and complex infrastructures. However, the main challenge faced in solar desalination is salt accumulation, either on the surface of or inside the solar evaporator, which can impair solar-to-vapor efficiency and even lead to the failure of the evaporator itself. While many ideas have been tried to address this ″salt accumulation″, scientists have not had a clear system for understanding what works best for the enhancement of salt-rejecting ability. Therein, for the first time, we classified the state-of-the-art salt-rejecting designs into isolation strategy (isolating the solar evaporator from brine), dilution strategy (diluting the concentrated brine), and crystallization strategy (regulating the crystallization site into a tiny area). Through the specific equations presented, we have identified key parameters for each strategy and highlighted the corresponding improvements in the solar desalination performance. This Review provides a semiquantitative perspective on salt-rejecting designs and critical parameters for enhancing the salt-rejecting ability of dilution-based, isolation-based, and crystallization-based solar evaporators. Ultimately, this knowledge can help us create reliable solar desalination solutions to provide clean water from even the saltiest sources.

Solar-Driven Multistage Device Integrating Dropwise Condensation and Guided Water Transport for Efficient Freshwater and Salt Collection

Interfacial solar vapor generation (ISVG) is an emerging technology to alleviate the global freshwater crisis. However, high-cost, low freshwater collection rate, and salt-blockage issues significantly hinder the practical application of solar-driven desalination devices based on ISVG. Herein, with a low-cost copper plate (CP), nonwoven fabric (NWF), and insulating ethylene-vinyl acetate foam (EVA foam), a multistage device is elaborately fabricated for highly efficient simultaneous freshwater and salt collection. In the designed solar-driven device, a superhydrophobic copper plate (SH-CP) serves as the condensation layer, facilitating rapid mass and heat transfer through dropwise condensation. Moreover, the hydrophilic NWF is designed with rational hydrophobic zones and specific high-salinity solution outlets (Design-NWF) to act as the water evaporation layer and facilitate directional salt collection. As a result, the multistage evaporator with eight stages exhibits a high water collection rate of 2.25 kg m-2 h-1 under 1 sun irradiation. In addition, the desalination device based on the eight-stage evaporator obtains a water collection rate of 13.44 kg m-2 and a salt collection rate of 1.77 kg m-2 per day under natural irradiation. More importantly, it can maintain a steady production for 15 days without obvious performance decay. This bifunctional multistage device provides a feasible and efficient approach for simultaneous desalination and solute collection.

Boosted light absorption by WO3-x/Ag/PbS heterostructure for high-efficiency interfacial solar steam generation

Interfacial solar steam generation is considered a promising approach to address energy and drinking water shortages. However, designing efficient light-absorbing and photothermal-converting materials remains challenging. In this study, we describe a detailed method for synthesising a three-dimensional (3D) hierarchical oxygen defect-rich WO3/Ag/PbS/Ni foam (termed WO3-x/Ag/PbS/NF) composite to realise efficient exciton separation and enhanced photothermal conversion. The 3D heterogeneous ternary photothermal material combines the individual benefits of WO3-x, Ag and PbS, improving charge transfer and promoting photogenerated electron-hole pairs. This enhances light absorption and energy conversion. Theoretical calculations indicate that the increased photothermal conversion efficiency primarily results from the heterojunction between Ag, WO3-x and PbS, facilitating exciton separation and electron transfer. Consequently, the WO3-x/Ag/PbS/NF solar evaporator exhibits exceptional light absorption (98% within the sunlight spectrum), a high evaporation rate of 1.90 kg m-2h-1 under 1 sun and a light-to-heat conversion efficiency of 94%. The WO3-x/Ag/PbS/NF evaporator also exhibits excellent capabilities in seawater desalination and wastewater treatment. This approach introduces a synergistic concept for creating novel multifunctional light-absorbing materials suitable for various energy-related applications.

Well-designed lamellar reduced graphene oxide-based foam for high-performance solar-driven water purification

Although solar steam generation is promising for seawater desalination, it is less effective in purifying wastewater with both salt/heavy metal ions and organic contaminants. It is thus imperative to develop multifunctional integrated solar-driven water purification systems with high solar-thermal evaporation and photocatalytic degradation efficiencies. Herein, a lamellar reduced graphene oxide (L-RGO) foam with the vertical lamellar structure is fabricated by bidirectional-freezing, lyophilization, and slight chemical reduction for water purification. The unique vertical lamellar structure not only accelerates upward transport of water for facilitating water evaporation but also endows the L-RGO foam with superb high elasticity for tuning the interlayer distance and varying interactions between the oxygen-containing groups and water molecules to adjust water energy state. As a result, the L-RGO foam achieves a superb water evaporation rate of 2.40 kg m-2 h-1 along with an energy efficiency of 95.3 % under the compressive strain of 44.7 % under 1-sun irradiation. Equally importantly, the decoration of L-RGO foam with polypyrrole is capable of efficiently degrading organic pollutants while retaining high solar steam generation performances, exhibiting great potential in the comprehensive treatment of various water sources for relieving freshwater crisis.

Recent Advances in Laser-Induced Graphene-Based Materials for Energy Storage and Conversion

Laser-induced graphene (LIG) is a porous carbon nanomaterial that can be produced by irradiation of CO2 laser directly on the polymer substrate under ambient conditions. LIG has many merits over conventional graphene, such as simple and fast synthesis, tunable structure and composition, high surface area and porosity, excellent electrical and thermal conductivity, and good flexibility and stability. These properties make LIG a promising material for energy applications, such as supercapacitors, batteries, fuel cells, and solar cells. In this review, we highlight the recent advances of LIG in energy materials, covering the fabrication methods, performance enhancement strategies, and device integration of LIG-based electrodes and devices in the area of hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, zinc-air batteries, and supercapacitors. This comprehensive review examines the potential of LIG for future sustainable and efficient energy material development, highlighting its versatility and multifunctionality in energy conversion.

Hydrophobic Surface Array Structure Based on Laser-Induced Graphene for Deicing and Anti-Icing Applications

The exceptional performance of graphene has driven the advancement of its preparation techniques and applications. Laser-induced graphene (LIG), as a novel graphene preparation technique, has been applied in various fields. Graphene periodic structures created by the LIG technique exhibit superhydrophobic characteristics and can be used for deicing and anti-icing applications, which are significantly influenced by the laser parameters. The laser surface treatment process was simulated by a finite element software analysis (COMSOL Multiphysics) to optimize the scanning parameter range, and the linear array surface structure was subsequently fabricated by the LIG technique. The generation of graphene was confirmed by Raman spectroscopy and energy-dispersive X-ray spectroscopy. The periodic linear array structure was observed by scanning electron microscopy (SEM) and confocal laser imaging (CLSM). In addition, CLSM testings, contact angle measurements, and delayed icing experiments were systematically performed to investigate the effect of scanning speed on surface hydrophobicity. The results show that high-quality and uniform graphene can be achieved using the laser scanning speed of 125 mm/s. The periodic linear array structures can obviously increase the contact angle and suppress delayed icing. Furthermore, these structures have the enhanced ability of the electric heating deicing, which can reach 100 °C and 240 °C within 15 s and within 60 s under the DC voltage power supply ranging from 3 to 7 V, respectively. These results indicate that the LIG technique can be developed to provide an efficient, economical, and convenient approach for preparing graphene and that the hydrophobic surface array structure based on LIG has considerable potential for deicing and anti-icing applications.

Machine Learning-Assisted Automatically Electrochemical Addressable Cytosensing Arrays for Anticancer Drug Screening

The high-throughput and accurate screening of anticancer drugs is crucial to the preclinical assessment of candidate drugs and remains challenging. Herein, an automatically electrochemical addressable cytosensor (AEAC) for the efficient screening of anticancer drugs is reported. This sensor consists of sectionalized laser-induced graphene arrays decorated by the rhombohedral TiO2 and spherical Pt nanoparticles (LIG-TiO2-Pt) with high electrocatalytic activity for H2O2 and a homemade Ag/Pt electrode couple fixed onto the robot arm. The immobilization of laminin on the surface of LIG-TiO2-Pt can promote its biocompatibility for the growth and proliferation of various tumor cells, which empowers the in situ monitoring of H2O2 directly released from these live cells for drug screening. A machine learning (ML) algorithm is employed to eliminate the possible random or systematic errors of AEAC, realizing rapid, high-throughput, and accurate prediction of different types of anticancer drugs. This ML-assisted AEAC provides a powerful approach to accelerate the evolution of sensing-served tumor therapy.

One-step fabrication of all-in-one three-dimensional porous polypyrrole/polydopamine structure for efficient solar vapor generation

High-quality solar evaporators with all-in-one design are highly desirable for vapor generation, but relevant research is scarce. In this study, a three-dimensional (3D) porous polypyrrole/polydopamine (PPY/PDA) structure was fabricated via a simple heating-assisted rapid oxidative polymerization method. The obtained evaporator has multiple features, and can simultaneously provide rapid water transport channels (average pore sizes ∼ 18.37 nm), low thermal conductivity (0.071 W m-1 K-1), high solar absorbance (97.08%), and good mechanical properties. When it is employed as an evaporator, the calculated water evaporation rate is approximately 2.12 kg m-2h-1, which is comparable to other reported 3D evaporators. Additionally, the evaporator displays great potential for purification toward various nonpotable water, as well as reliable pure water yields in an outdoor application (from 8:00 am to 5:00 pm, the evaporator can produce at least 13.95 L of drinkable water for a 1 m2 sample). We believe that the proposed strategy to fabricate all-in-one evaporators has great significance for scientific research and practical applications.

Advances in photothermal regulation strategies: from efficient solar heating to daytime passive cooling

Photothermal regulation concerning solar harvesting and repelling has recently attracted significant interest due to the fast-growing research focus in the areas of solar heating for evaporation, photocatalysis, motion, and electricity generation, as well as passive cooling for cooling textiles and smart buildings. The parallel development of photothermal regulation strategies through both material and system designs has further improved the overall solar utilization efficiency for heating/cooling. In this review, we will review the latest progress in photothermal regulation, including solar heating and passive cooling, and their manipulating strategies. The underlying mechanisms and criteria of highly efficient photothermal regulation in terms of optical absorption/reflection, thermal conversion, transfer, and emission properties corresponding to the extensive catalog of nanostructured materials are discussed. The rational material and structural designs with spectral selectivity for improving the photothermal regulation performance are then highlighted. We finally present the recent significant developments of applications of photothermal regulation in clean energy and environmental areas and give a brief perspective on the current challenges and future development of controlled solar energy utilization.

Synergistic Dual-Mechanism Localized Heat Channeling and Spectrum-Tailored Liquid Metal Hydrogels for Efficient Solar Water Evaporation and Desalination

Photothermal hydrogels featuring broadband light absorption abilities and highly hydrated networks provide an appealing mass-energy transfer platform for water evaporation by using solar energy. However, the targeted delivery of solar heat energy to power the water evaporation process remains challenging. Herein, enlightened by metal-phenolic coordination chemistry and camouflaged architecture, photothermal hydrogels with dual-mechanism vaporization structure are tactfully designed via a rational interfacial engineering and integration strategy to enable near-µm heat confinement and highly efficient light-to-heat conversion ability. The spectrum-tailored liquid metal droplet (LMGAs-FeIII ) and optimized carbon-wrapped silver nanowire sponge (Ag@C750 ) are integrally built as photothermal promotors/channels and jointly embedded into a highly hydratable poly(vinyl alcohol) hydrogel, denoted as PALGH, to synergistically boost water molecule activation and interfacial vaporization behavior by triggering robust photothermal performance. As a result, under one sun irradiation, the all-embracing PALGH hydrogel evaporation system achieves a brine evaporation rate to a high level of 3.47 kg m-2 h-1 , and >19 L m-2 clean water of PALGH is ideally delivered daily when purifying natural seawater. This work offers not only a rational design principle to create sophisticated photothermal materials but also replenishes insight into solar heat generation and water transportation in a cross-media system.

Functional Materials and Innovative Strategies for Wearable Thermal Management Applications

Highlights

This article systematically reviews the thermal management wearables with a specific emphasis on materials and strategies to regulate the human body temperature. Thermal management wearables are subdivided into the active and passive thermal managing methods. The strength and weakness of each thermal regulatory wearables are discussed in details from the view point of practical usage in real-life.

Abstract

Thermal management is essential in our body as it affects various bodily functions, ranging from thermal discomfort to serious organ failures, as an example of the worst-case scenario. There have been extensive studies about wearable materials and devices that augment thermoregulatory functionalities in our body, employing diverse materials and systematic approaches to attaining thermal homeostasis. This paper reviews the recent progress of functional materials and devices that contribute to thermoregulatory wearables, particularly emphasizing the strategic methodology to regulate body temperature. There exist several methods to promote personal thermal management in a wearable form. For instance, we can impede heat transfer using a thermally insulating material with extremely low thermal conductivity or directly cool and heat the skin surface. Thus, we classify many studies into two branches, passive and active thermal management modes, which are further subdivided into specific strategies. Apart from discussing the strategies and their mechanisms, we also identify the weaknesses of each strategy and scrutinize its potential direction that studies should follow to make substantial contributions to future thermal regulatory wearable industries.

CO2-laser-induced carbonization of calcium chloride-treated chitin nanopaper for applications in solar thermal heating

Remarkable progress has been made in the development of carbonized chitin nanofiber materials for various functional applications, including solar thermal heating, owing to their N- and O-doped carbon structures and sustainable nature. Carbonization is a fascinating process for the functionalization of chitin nanofiber materials. However, conventional carbonization techniques require harmful reagents, high-temperature treatment, and time-consuming processes. Although CO₂ laser irradiation has progressed as a facile and second-scale high-speed carbonization process, CO₂-laser-carbonized chitin nanofiber materials and their applications have not yet been explored. Herein, we demonstrate the CO₂-laser-induced carbonization of chitin nanofiber paper (denoted as chitin nanopaper) and investigate the solar thermal heating performance of the CO₂-laser-carbonized chitin nanopaper. While the original chitin nanopaper was inevitably burned out by CO₂ laser irradiation, CO₂-laser-induced carbonization of the chitin nanopaper was achieved by pretreatment with calcium chloride as a combustion inhibitor. The CO₂-laser-carbonized chitin nanopaper exhibits excellent solar thermal heating performance; its equilibrium surface temperature under 1 sun irradiation is 77.7 °C, which is higher than those of the commercial nanocarbon films and the conventionally carbonized bionanofiber papers. This study paves the way for the high-speed fabrication of carbonized chitin nanofiber materials and their application in solar thermal heating toward the effective utilization of solar energy as heat.

Pattern-Dependent Radio Frequency Heating of Laser-Induced Graphene Flexible Heaters

Graphene is an excellent choice for heating applications due to its high thermal conductivity and is considered an interesting candidate for application in flexible heaters. The major challenge, though, is the costly and chemical-intensive pathways to produce graphene on a large scale. Laser ablation of polymeric substrates is a relatively recent technique for a facile, single-step, chemical-free fabrication of graphene, referred to as laser-induced graphene (LIG). This work demonstrates the fabrication of patterned LIG-based flexible heaters and their response to radio frequency (RF) electromagnetic waves. Polymeric substrates were scribed with laser patterns in both raster and vector modes and subjected to RF electromagnetic fields to test their heating response. We confirmed different graphene morphologies of the lased patterns through various materials characterization methods. The maximum steady-state temperature observed for the LIG heater was approximately 500 °C. Unprecedented heating rates, as high as 502 °C/s, were observed when LIG heaters were exposed to RF fields at 200 MHz frequency and 4.6 W power. Mechanical and thermal stability tests for the best heater were also performed showing a stable thermal response for 1000 bending cycles and 20 cycles of the heating test for 8.5 h, respectively. Our work suggests that LIG heaters produced in vector mode lasing outperformed those lased in raster mode which can be attributed to the improved graphene quality for RF absorbance.

Highly Efficient, Antibacterial, and Salt-Resistant Strategy Based on Carbon Black/Chitosan-Decorated Phase-Change Microcapsules for Solar-Powered Seawater Desalination

Solar-powered interfacial evaporation has been recognized to be a promising and sustainable technology for seawater desalination, in view of the challenge of freshwater scarcity and fossil energy storage. Nevertheless, current cutting-edge interfacial evaporation systems mostly ignore the issues of intermittent solar irradiation and bacterial contamination. We have hereby developed a novel type of an interfacial evaporator equipped with carbon black (CB)/chitosan (CS)-decorated phase-change microcapsules as a multifunctional photothermal material for solar-powered seawater desalination, based on a highly efficient, antibacterial, and salt-resistant multipurpose strategy. In the developed microcapsules, an n-docosane phase-change material (PCM) core was engulfed in a TiO₂ shell, followed by surface decorating a CB/CS nanocomposite layer. A high thermal energy-storage capacity of more than 140 J g^-1 was achieved, thanks to tight sealing of n-docosane as a PCM core in the perfect core-shell structured microcapsules. Moreover, a rational combination of CS and CB nanoparticles not only contributes an extremely high solar absorption efficiency of 95.04% and good wettability to the as-synthesized microcapsules, but also imparts outstanding antibacterial and salt-resistant abilities to them. These innovative designs enable the developed evaporator to gain a high evaporation rate of 2.58 kg m^-2 h^-1, along with an evaporation efficiency higher than 90% for consecutive and stable evaporation of seawater under intermittent solar illumination. Compared to conventional evaporators without a PCM, there is an increase by 1.03 kg m^-2 in the total water production of the develop evaporator under natural solar illumination for 8 h on a semicloudy day. The resultant evaporated water presents good vegetation compatibility to meet the requirement of crop growth for agricultural cultivation. This work provides a new pathway for designing and developing the high-performance interfacial evaporators with prominent antibacterial and salt-resistant abilities to produce purified water through solar-powered sustainable seawater desalination.

Direct Conversion of Liquid Organic Precursor into 3D Laser-Induced Graphene Materials

Among the different states of matter, liquids have particular advantages in terms of easy handling and recycling, which has been manifested in various chemosynthetic reactions, but remains underexplored in graphene synthesis. This work reports the direct conversion of liquid organic precursor into versatile 3D graphene materials using rapid laser irradiation. The liquid precursor allows for easy fabrication of graphene with significant 3D architectures, including powders, patterned composite structures, and substrate-free films. Taking advantage of the high compatibility of liquid precursor with a wide range of dopants, the 3D graphene can be further engineered together with various functional components, especially the high loading (≈15 wt.%) and well-dispersed (an average diameter of less than 50 nm) high-entropy alloy nanoparticles. Furthermore, combined with the 3D printing strategy, the rapid construction of graphene with complex and accurate 3D shapes is demonstrated via a selective in situ laser transforming (SLT) strategy. With the high structural integrity unachievable by traditional 3D printing methods, the obtained objects show an electrical conductivity of 4380 S m^-1 and a compressive modulus of 31.8 MPa. The results reported in this work will open up a new way for the fabrication of functional carbon materials with customizable shapes and components.

Upcycling of thermosetting polymers into high-value materials

Thermosetting polymers, a large class of polymers featuring excellent properties, have been widely used and play an irreplaceable role in our life. Nevertheless, they are arduous to be recycled or reused on account of their permanently cross-linked networks, and the main recycling approaches used currently include energy recovery through incineration, utilization as fillers after mechanical grinding, and pyrolysis, which only reclaim a small fraction or partial value of thermosetting polymers and their downstream materials. In this minireview, we provide an overview of the efforts undertaken towards upcycling thermosetting polymers in recent years. The research progress on physical upcycling, carbonization, solvolysis and vitrimerization of thermoset waste to high-value materials, including oil-water separation materials, 3D printable materials, functional carbon materials (supercapacitors, photothermal conversion materials, and catalytic materials), additives, emulsifiers, biolubricants, and vitrimers, are summarized and discussed. Perspectives on the future development of the art of upcycling thermosets are also provided.

Engineering Biomimetic Nanostructured "Melanosome" Textiles for Advanced Solar-to-Thermal Devices

In nature, deep-sea fish featured with close-packed melanosomes can remarkably lower light reflection, which have inspired us to design ultrablack coatings for enhanced solar-to-thermal conversion. Herein, a biomimetic ultrablack textile is developed enabled by the formation of hierarchical polypyrrole (Ppy) nanospheres. The fabricated textile exhibits prominently suppressed reflectance of lower than 4% and highly enhanced absorption of up to 96%. Further experimental results and molecular dynamics (MD) simulation evidence the formation process of hierarchical nanospheres. Based on high-efficient solar-to-thermal conversion, the biomimetic textile with desirable conductivity allows the development of a salt-free solar evaporator, enabling a sustainable seawater evaporation rate of up to 1.54 kg m^-2 h^-1 under 1 sun. Furthermore, the biomimetic hierarchical textile exhibits good superhydrophobicity, enhanced photothermal property, and high electrothermal conversion, demonstrating significant potential in wearable thermal management (rescue vests) in water conditions.

A fast curing assisted spray-coating method to fabricate a robust core-shell structured evaporator with stable solar vapor generation performance

Solar driven interfacial vapor generation is considered to be an effective strategy to alleviate the impact of water crisis on human activities. However, great efforts of researchers have been devoted to improving the solar steam generation efficiency, while less attention has been paid to the long-term stability of evaporators. Herein, we proposed a robust core-shell structured evaporator prepared by a simple fast curing assisted spray-coating method. Owing to the inherent superelasticity of melamine-formaldehyde (MF) sponge, the finely designed novel 3D core-shell structure, and the quick curing of branched polyethyleneimine (BPEI) and 5-pentaerythritol pentaacrylate (5Acl) induced special knot shaped photothermal coating, the as-obtained evaporator (CB/MF) performed well in vapor generation with a high water evaporation rate of 2.082 kg m^-2 h^-1 under 1 sun illumination, and the evaporation efficiency reached 123.5%, which is comparable to the state-of-the-art artificial solar evaporator. Even in strict application situations, such as long-term recycling testing for 40 h, 500 compression-release cycles (20%, 40% or 60%), sonication for 12 h, or shaking for 30 h, the water evaporation rate of the obtained evaporator remains at a high level of above 2.00 kg m^-2 h^-1. Additionally, the evaporator shows effective purification toward high-concentration brine, acid-base solutions, simulated seawater, dye wastewater, and heavy metal wastewater, as well as reliable pure water, providing an outdoor application. With the advantages of a high evaporation rate, stable long-term vapor generation, and effective purification toward various non-potable water sources, we believe that the fabricated core-shell structured CB/MF evaporator is a promising candidate for practical solar steam generation.

Bioinspired Micro/Nanostructured Polyethylene/Poly(Ethylene Oxide)/Graphene Films with Robust Superhydrophobicity and Excellent Antireflectivity for Solar-Thermal Power Generation, Thermal Management, and Afterheat Utilization

The rational utilization and circulation of multiple energy sources is an effective way to address the crises of energy shortages and environmental pollution. Herein, microextrusion compression molding, an industrialized polymer molding technology that combines melt blending and compression molding, is proposed for the mass production of a bioinspired micro/nanostructured polyethylene/poly(ethylene oxide)/graphene (MN-PPG) film. The MN-PPG film exhibits robust shape stability, high storage energy density, and excellent thermal management capability owing to the cocontinuous network formed by poly(ethylene oxide) and the polyethylene matrix. The MN-PPG film has sufficient photothermal property due to the uniformly dispersed graphene nanosheets and the bioinspired surface micro/nanostructures. Interestingly, the MN-PPG film surface exhibits durable superhydrophobicity, acid/alkali resistance, and active deicing performance. Further, a multifunctional energy harvesting and circulation system was established by integrating the MN-PPG film, an LED chip, and a thermoelectric module. The hybrid system produced an open-circuit voltage of 315.4 mV and power output of 2.5 W m^-2 under 3 sun irradiation. Furthermore, the afterheat generated by the LED chips at night can be converted into electricity through thermoelectric conversion. The proposed method enables the large-scale fabrication of multifunctional phase change composites for energy harvesting in harsh environments.

A Trimode Thermoregulatory Flexible Fibrous Membrane Designed with Hierarchical Core-Sheath Fiber Structure for Wearable Personal Thermal Management

Advanced textiles designed for personal thermal management contribute to thermoregulation in an individual and energy-saving manner. Textiles incorporated with phase changing materials (PCMs) are capable of bridging the supply and demand for energy by absorbing and releasing latent heat. The integration of solar heating and the Joule heating function supplies multidriving resources, facilitates energy charging and storage, and expands the service time and application scenarios. Herein, we report a fibrous membrane-based textile that was developed by designing the hierarchical core-sheath fiber structure for trimode thermal management. Especially, coaxial electrospinning allows an effective encapsulation of PCMs, with high heat enthalpy density (106.9 J/g), enabling the membrane to buffer drastic temperature changes in the clothing microclimate. The favorable photothermal conversion performance renders the membrane with the high saturated temperature of 70.5 °C (1 sun), benefiting from the synergistic effect of multiple light harvesters. Moreover, a conductive coating endows the composite membrane with an admirable electrothermal conversion performance, reaching a saturated temperature of 73.8 °C (4.2 V). The flexible fibrous membranes with the integrated performance of reversible phase change, multi-source-driven heating, and energy storage present great advantages for all-day, energy-saving, and wearable individual thermal management applications.

Wettability Controlled Surface for Energy Conversion

To achieve clean and high-efficiency utilization of renewable energy, functional surfaces with controllable and patternable wettability are becoming a fast-growing research focus. In this work, a laser scribing strategy to fabricate patterned graphene surfaces that are capable of energy conversion in different forms is demonstrated. Using the laser raster-scanning and vector-scanning modes, two distinct surface structures are constructed on polybenzoxazine substrate, yielding a superhydrophilic (LSHL) surface and superhydrophobic (LSHB) surface, respectively. Of particular note is that the unique hierarchical structure of LSHB surface has endowed it with quite a robust superwetting behaviors. Further profiting from the flexibility of the processing method, wettability patterns with spatially resolved LSHL and LSHB regions are designed, achieving the conversion of surface energy to liquid kinetic energy. This also offers a tractable approach to fabricate wettability-engineered devices that enable the directional, pumpless transport of water by capillary pressure gradient and the selective surface cooling via jet impingement. In addition, the LSHB surface demonstrates the high conversion of electric-to-thermal energy (222 °C cm² W^-1 ) and light-to-thermal energy (88%). Overall, the material system and processing method present a promising step forward to developing easy-fabricated graphene surfaces with spatially controlled wettability for efficient energy utilization and conversion.

Laser Processing of Flexible In-Plane Micro-supercapacitors: Progresses in Advanced Manufacturing of Nanostructured Electrodes

Flexible in-plane architecture micro-supercapacitors (MSCs) are competitive candidates for on-chip miniature energy storage applications owing to their light weight, small size, high flexibility, as well as the advantages of short charging time, high power density, and long cycle life. However, tedious and time-consuming processes are required for the manufacturing of high-resolution interdigital electrodes using conventional approaches. In contrast, the laser processing technique enables high-efficiency high-precision patterning and advanced manufacturing of nanostructured electrodes. In this review, the recent advances in laser manufacturing and patterning of nanostructured electrodes for applications in flexible in-plane MSCs are comprehensively summarized. Various laser processing techniques for the synthesis, modification, and processing of interdigital electrode materials, including laser pyrolysis, reduction, oxidation, growth, activation, sintering, doping, and ablation, are discussed. In particular, some special features and merits of laser processing techniques are highlighted, including the impacts of laser types and parameters on manufacturing electrodes with desired morphologies/structures and their applications on the formation of high-quality nanoshaped graphene, the selective deposition of nanostructured materials, the controllable nanopore etching and heteroatom doping, and the efficient sintering of nanometal products. Finally, the current challenges and prospects associated with the laser processing of in-plane MSCs are also discussed. This review will provide a useful guidance for the advanced manufacturing of nanostructured electrodes in flexible in-plane energy storage devices and beyond.

Research Progress on the Preparation and Applications of Laser-Induced Graphene Technology

Graphene has been regarded as a potential application material in the field of new energy conversion and storage because of its unique two-dimensional structure and excellent physical and chemical properties. However, traditional graphene preparation methods are complicated in-process and difficult to form patterned structures. In recent years, laser-induced graphene (LIG) technology has received a large amount of attention from scholars and has a wide range of applications in supercapacitors, batteries, sensors, air filters, water treatment, etc. In this paper, we summarized a variety of preparation methods for graphene. The effects of laser processing parameters, laser type, precursor materials, and process atmosphere on the properties of the prepared LIG were reviewed. Then, two strategies for large-scale production of LIG were briefly described. We also discussed the wide applications of LIG in the fields of signal sensing, environmental protection, and energy storage. Finally, we briefly outlined the future trends of this research direction.

Dual Defocused Laser Pyrolysis: A Lasing-Centric Strategy for Defect and Morphological Optimization in Microsupercapacitor Electrodes

Laser-induced graphene (LIG) has shown great potential for controllable and scalable realization of microsupercapacitors (MSCs). However, as is well-known, LIG electrodes suffer from low charge storage capacity and conductance. In this paper, a lasing-centric method is presented for defect control and morphological enhancement in LIG electrodes through unique dual laser pyrolysis. This method encompasses dual lasing pyrolysis, one for the synthesis of defocused LIG, and another for the decoration of Ru nanoparticles to enhance electrochemical performance. Fundamentally, the investigation simultaneously optimizes for defocused lasing distance and lasing speed, which to the best of the author's knowledge, has not been previously reported. The defocused LIG electrode exhibits a remarkably improved electrochemical capacitance of over 25 times (114 mF cm^-2 ) compared to the one based on focused laser-induced graphene (FLIG). As a device demonstration, a flexible and self-healable MSC has been fabricated based on DFLIG/Ru-PEDOT/Au electrodes, exhibiting a high areal specific capacitance (25.7 mF cm^-2 ), excellent electrochemical stability (91% retention of specific capacitance after 8000 cycles), and good self-healing performance (85.6% retention of specific capacitance after two cut-heal cycles). By enhancing material properties via dual defocused laser pyrolysis, this work presents a strategy for highly controllable and scalable realization of electrodes in micro-energy storage devices.

Metal-Organic Framework Composite Photothermal Membrane for Removal of High-Concentration Volatile Organic Compounds from Water via Molecular Sieving

Water-soluble volatile organic compounds (VOCs) are among the most difficult-to-treat species during wastewater treatment. The current purification and removal of high-concentration VOCs still rely on the energy-consuming distillation and high-pressure driven reverse osmosis technology. There is an urgent need for an advanced technology that can effectively remove high-concentration VOCs from water. Here, we report a metal-organic framework (MOF)/polyaniline (PANI) nanofiber array composite photothermal membrane for removal of high-concentration VOCs from water via molecular sieving during a solar-driven evaporation process. The modified zeolitic imidazole framework-8 (ZIF-8) layer grown on a PANI nanofiber array acts as a molecular sieving layer to evaporate water but intercept VOCs. The composite membrane exhibits high VOCs rejection and a high-water evaporation rate for water containing different concentrations of VOCs. When treating water containing VOCs with a concentration of up to 400 mg L^-1, the VOCs rejection rate is up to 99% and the water evaporation rate is 1.0 kg m^-2 h^-1 under 1 sun irradiation (1 kW m^-2). Our work effectively combines the molecular sieve effect with a solar-driven evaporation process, which provides an effective strategy for the treatment of water containing VOCs.

Pitaya-Structured Microspheres with Dual Laser Wavelength Responses for Polymer Laser Direct Writing

A unique pitaya-structured graphene/TiO₂@PS microsphere with dual laser wavelength responses is designed and prepared via a facile approach of polymer melt blending. The graphene/TiO₂ particles ("pitaya seeds") are homogeneously distributed in the polystyrene ("pitaya pulp") of the microspheres with an average size of 1.5 μm. The graphene in microspheres serves not only as a laser absorber that has responses to both 355 nm UV and 1064 nm NIR lasers but also as a reducing agent of TiO₂ during laser direct writing (LDW). As expected, benefiting from the unique pitaya-structured structure, the graphene/TiO₂@PS microsphere can remarkably improve the performance of both NIR and UV LDW of polymers. The results of characterizations reveal that the black color caused by NIR LDW is due to the generation of the amorphous carbon and the color change after UV LDW is owing to the formation of black sp/sp² carbon compounds. Meanwhile, some TiO₂ in microspheres is reduced into the black/gray titanium oxides of Ti²⁺ and Ti³⁺ after NIR and UV LDW, respectively. The above co-contribution endows the graphene/TiO₂@PS microspheres with an outstanding color-changing ability. This pitaya-structured microsphere will have a profound effect on polymers' laser direct writing.

Green Synthesis of Laser-Induced Graphene with Copper Oxide Nanoparticles for Deicing Based on Photo-Electrothermal Effect

Homogenously dispersed Cu oxide nanoparticles on laser-induced graphene (LIG) were fabricated using a simple two-step laser irradiation. This work emphasized the synergetic photo-electrothermal effect in Cu oxide particles embedded in LIG. Our flexible hybrid composites exhibited high mechanical durability and excellent thermal properties. Moreover, the Cu oxide nanoparticles in the carbon matrix of LIG enhanced the light trapping and multiple electron internal scattering for the electrothermal effect. The best conditions for deicing devices were also studied by controlling the amount of Cu solution. The deicing performance of the sample was demonstrated, and the results indicate that the developed method could be a promising strategy for maintaining lightness, efficiency, excellent thermal performance, and eco-friendly 3D processing capabilities.