Photocatalytic Bacterial Inactivation by a Rape Pollen-MoS2 Biohybrid Catalyst: Synergetic Effects and Inactivation Mechanisms

Efficient inactivation of antibiotic resistant bacteria by iron-modified biochar and persulfate system: Potential for controlling antimicrobial resistance spread and mechanism insights

Antimicrobial resistance (AMR) is a critical global health threat, further intensified by the widespread dissemination of plasmid-encoded antibiotic resistance genes (ARGs), which poses a significant challenge to the "One Health" concept. Persulfate-based advanced oxidation processes (PS-AOPs) have emerged as effective disinfection methods, capable of degrading antibiotics, inactivating bacteria, and eliminating ARGs, whereas their efficacy towards blocking ARGs horizontal transfer remains elusive. This work constructed a series of Fe-modified soybean straw biochar (FeSSB) as persulfate (PS) activators through Fe-modification and temperature regulation. Among the tested systems, FeSSB800/PS achieved complete inactivation of antibiotic resistant bacteria (ARB) with a 7.04-log reduction within 60 min, outperforming others. FeSSB800, featuring the highest exposed-Fe(II) sites, most CO groups, and lowest charge transfer resistance, obtaining optimal PS activation and reactive species generation, which caused irreversible damage to ARB cells and significantly inhibited the transformation and conjugation efficiency of plasmid RP4. The inhibition mechanism is driven by the aggressive action of free radicals, which injure cell envelopes, induce oxidative stress, disrupt ATP synthesis, and alter intercellular adhesion. These findings underscore the potential of PS-AOPs as a promising strategy to mitigate AMR by simultaneously inactivating ARB and impeding ARGs dissemination.

Piezoelectric Amplification of Cascade Enzymatic Catalysis and Nanomotor Propulsion for Synergistic Electrodynamic-Starvation Tumor Therapy

Piezoelectrodynamic therapy (PEDT) is compromised by hypoxia dilemma of tumors, while starvation therapy is constrained by insufficient enzyme activities. To address these challenges, Janus piezoelectric nanoparticles (NPs) are proposed to spatially immobilize glucose oxidase (GOx) and catalase (CAT), enabling piezoelectric potential-amplified enzyme activities and synergistic PEDT-starvation tumor therapy. Here hollow barium titanate (hBT) NPs are synthesized using SiO2 templates, followed by partial Au deposition via the Pickering emulsion-masking method to create Janus hBT@Au NPs, which are then conjugated with GOx and CAT on opposing sides to yield C-hBT@Au-G NPs. The hollow structure of hBT enhances flexibility and deformation under ultrasonication, while Schottky heterojunctions with Au layers promote charge carrier transfer, amplifying piezoelectric effects and free electron transfer to boost GOx activities. Piezoelectric field-enhances selective tumor cell internalization of NPs and PEDT generation of reactive oxygen species (ROS), coupled with self-propagated GOx/CAT cascades, intensify tumor cytotoxicities and deplete intracellular adenosine triphosphate. The Janus architecture, ultrasonic cavitation, and O2 generation collaboratively drive robust propulsion for efficient NP accumulation and deep ROS penetration into tumor tissues, thereby achieving full tumor suppression with negligible systemic toxicity. This design overcomes delivery barriers of tumor accumulation, intratumoral penetration, and cellular uptake and synergizes PEDT-starvation tumor therapy.

Nanosheet-shaped WS2/ICG nanocomposite for photodynamic/photothermal synergistic bacterial clearance and cutaneous regeneration on infectious wounds

Bacterial infections present a significant threat to human health, a challenge that is intensified by the slow pace of novel antibiotic development and the swift emergence of bacterial resistance. The development of novel antibacterial agents is crucial. Indocyanine green (ICG), a widely used imaging dye, efficiently generates reactive oxygen species (ROS) and heat for treating bacterial infections but suffers from aggregation and instability, limiting its efficacy. In this study, tungsten disulfide (WS₂) nanosheet with a high surface area was used to load ICG, creating a multifunctional nanocomposite, WS2/ICG, aimed at treating bacteria-infected wounds. The two-dimensional surface structure of WS₂ provides dispersible binding sites for ICG, and the synthesized nanocomposite exhibits excellent stability. Under near-infrared (NIR) laser excitation, the generated heat further synergistically enhances the yield of singlet oxygen. Additionally, the WS₂/ICG nanoplatform synergistically combines photothermal effect with photodynamic effect, achieving a "1 + 1 > 2" enhancement. Upon NIR laser excitation, the nanocomposite disrupts bacterial cell membranes through localized heating and ROS accumulation, leading to energy metabolism system disruption and subsequent bacterial lysis and death. The findings demonstrate WS₂/ICG's outstanding antibacterial properties and biocompatibility, effectively treating skin infections and promoting tissue regeneration, providing a simple and promising solution for bacteria-infected wounds.

Unveiling the synergistic interface effects of Ag-deposited Fe2O3/biochar catalysts to enhance wastewater degradation

Photo-Fenton reaction is a sustainable and cost-effective wastewater treatment strategy capable of removing persistent organic pollutants. We utilized biochar (referred to as C) as a key component to enhance catalytic efficiency. Using a biomimetic templating method, we synthesized Fe2O3 on the biochar and deposited Ag on its surface, resulting in the Ag@Fe2O3/C composite material (referred to as AFC). In the photo-Fenton system, the AFC material achieved a 99% degradation rate of methylene blue (MB) within 30 minutes, which is 8.5 times and 6.4 times higher than that of photocatalysis and Fenton reaction alone, respectively. Using Escherichia coli as a model, AFC achieved a 100% bactericidal rate within 6 minutes in the photo-Fenton system. This material effectively treated aquaculture wastewater, removing most impurities and colorants. By introducing Ag nanoparticles as electron transfer centers, the electron transfer efficiency was enhanced, accelerating the catalytic reaction and improving the composite's adsorption capacity for H2O2 and organic pollutants. Analysis revealed the migration pathways of photogenerated electrons and holes in AFC, providing a theoretical foundation and practical direction for the design of future photocatalytic materials and the treatment of organic pollutants.

Unveiling the photocatalytic marvels: Recent advances in solar heterojunctions for environmental remediation and energy harvesting

In the quest for effective solutions to address Environ. Pollut. and meet the escalating energy demands, heterojunction photocatalysts have emerged as a captivating and versatile technology. These photocatalysts have garnered significant interest due to their wide-ranging applications, including wastewater treatment, air purification, CO2 capture, and hydrogen generation via water splitting. This technique harnesses the power of semiconductors, which are activated under light illumination, providing the necessary energy for catalytic reactions. With visible light constituting a substantial portion (46%) of the solar spectrum, the development of visible-light-driven semiconductors has become imperative. Heterojunction photocatalysts offer a promising strategy to overcome the limitations associated with activating semiconductors under visible light. In this comprehensive review, we present the recent advancements in the field of photocatalytic degradation of contaminants across diverse media, as well as the remarkable progress made in renewable energy production. Moreover, we delve into the crucial role played by various operating parameters in influencing the photocatalytic performance of heterojunction systems. Finally, we address emerging challenges and propose novel perspectives to provide valuable insights for future advancements in this dynamic research domain. By unraveling the potential of heterojunction photocatalysts, this review contributes to the broader understanding of their applications and paves the way for exciting avenues of exploration and innovation.

Recyclable Biomimetic Sunflower Pollen-based Photocatalyst for Enhanced Degradation of Pharmaceuticals

Recent trends in addressing the impending water crisis focus on the development of innovative water treatment methods. This work utilizes pollen as a core template to synthesize highly efficient onion-like photocatalysts for pollutant mineralization. The study showcases a novel electrochemical synthesis method that maintains the structural integrity of pollen, resulting in increased surface area and enhanced photocatalytic activity. After 90-min of visible light irradiation, over 99% mineralization is achieved. These hybrid photocatalysts demonstrate exceptional stability and efficacy in degrading pollutants. The used photocatalysts can be recycled into biopellets with an ash content of less than 7% (weight), moisture content of less than 8% (weight), and a calorific value of ≈22.1 ± 0.3 MJ kg-1. Additionally, the resulting ashes serve as effective peroxymonosulphate activators for pollutant mineralization. This process offers sustainable waste management while minimizing waste production, providing a practical solution for water purification. The efficacy of this approach in pollutant removal is underscored by mineralization rates exceeding 99%.

Revisiting Solar Energy Flow in Nanomaterial-Microorganism Hybrid Systems

Nanomaterial-microorganism hybrid systems (NMHSs), integrating semiconductor nanomaterials with microorganisms, present a promising platform for broadband solar energy harvesting, high-efficiency carbon reduction, and sustainable chemical production. While studies underscore its potential in diverse solar-to-chemical energy conversions, prevailing NMHSs grapple with suboptimal energy conversion efficiency. Such limitations stem predominantly from an insufficient systematic exploration of the mechanisms dictating solar energy flow. This review provides a systematic overview of the notable advancements in this nascent field, with a particular focus on the discussion of three pivotal steps of energy flow: solar energy capture, cross-membrane energy transport, and energy conversion into chemicals. While key challenges faced in each stage are independently identified and discussed, viable solutions are correspondingly postulated. In view of the interplay of the three steps in affecting the overall efficiency of solar-to-chemical energy conversion, subsequent discussions thus take an integrative and systematic viewpoint to comprehend, analyze and improve the solar energy flow in the current NMHSs of different configurations, and highlighting the contemporary techniques that can be employed to investigate various aspects of energy flow within NMHSs. Finally, a concluding section summarizes opportunities for future research, providing a roadmap for the continued development and optimization of NMHSs.

Bioprotective Respirator Assembled by Defective Carbon Nitride for Long-Term Light Triggered Health Protection

Wearing face masks is the best way to stop the spread of respiratory infections. However, if masks are not sterilized, changing them too frequently can actually increase the risk of cross-contamination. Herein, the construction of an antipathogen photocatalytic mask with carbon vacancy-modified carbon nitride nanosheets (g-C3N4-VC Ns) coated on the non-woven fabrics of the out layer of the mask, offering effective and long-term protection against damaging pathogens when exposed to light is reported. The introduced carbon vacancies are found capable of creating energy-disordered sites and inducing energetic electric force to overcome the Coulomb interactions between electron-hole pairs, thus promoting the electron-hole separation to achieve a high generation of reactive oxygen species (ROS). Thanks to its high activity in generating ROS upon exposure to light, the as-prepared photocatalytic mask shows high pathogen sterilization performance. This, in turn, prolongs the mask's protective lifetime, decreases the need for regular replacement, and decreases medical waste production. The work demonstrated here opens new viewpoints in designing pathogens biocidal protective devices for health protection, offering significant promise in specific environment self-protection.

The development of multifunctional materials for water pollution remediation using pollen and sporopollenin

Pollen is a promising material for water treatment owing to its renewable nature, abundant sources, and vast reserves. The natural polymer sporopollenin, found within pollen exine, possesses a distinctive layered porous structure, mechanical strength, and stable chemical properties, which can be utilized to prepare sporopollenin exine capsules (SECs). Leveraging these attributes, pollen or SECs can be used to develop water pollution remediation materials. In this review, the structure of pollen is first introduced, followed by the categorization of various methods for extracting SECs. Then, the functional expansion of pollen adsorbents, with an emphasis on their recyclability, reusability, and visual sensing capabilities, as opposed to mere functional group modification, is discussed. Furthermore, the progress made in utilizing pollen as a biological template for synthesizing catalysts is summarized. Intriguingly, pollen can also be engineered into self-propelled micromotors, enhancing its potential application in adsorption and catalysis. Finally, the challenges associated with the application of pollen in water pollution treatment are discussed. These challenges include the selection of environmentally friendly, non-toxic reagents in synthesizing pollen water remediation products and the large-scale application after synthesis. Moreover, the multifunctional synthesis and application of different water remediation products are prospected.

Evaluating the Impact of Cl2•- Generation on Antibiotic-Resistance Contamination Removal via UV/Peroxydisulfate

The removal of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) using sulfate anion radical (SO4•-)-based advanced oxidation processes has gained considerable attention recently. However, immense uncertainties persist in technology transfer. Particularly, the impact of dichlorine radical (Cl2•-) generation during SO4•--mediated disinfection on ARB/ARGs removal remains unclear, despite the Cl2•- concentration reaching levels notably higher than those of SO4•- in certain SO4•--based procedures applied to secondary effluents, hospital wastewaters, and marine waters. The experimental results of this study reveal a detrimental effect on the disinfection efficiency of tetracycline-resistant Escherichia coli (Tc-ARB) during SO4•--mediated treatment owing to Cl2•- generation. Through a comparative investigation of the distinct inactivation mechanisms of Tc-ARB in the Cl2•-- and SO4•--mediated disinfection processes, encompassing various perspectives, we confirm that Cl2•- is less effective in inducing cellular structural damage, perturbing cellular metabolic activity, disrupting antioxidant enzyme system, damaging genetic material, and inducing the viable but nonculturable state. Consequently, this diminishes the disinfection efficiency of SO4•--mediated treatment owing to Cl2•- generation. Importantly, the results indicate that Cl2•- generation increases the potential risk associated with the dark reactivation of Tc-ARB and the vertical gene transfer process of tetracycline-resistant genes following SO4•--mediated disinfection. This study underscores the undesired role of Cl2•- for ARB/ARGs removal during the SO4•--mediated disinfection process.

Progress of disinfection catalysts in advanced oxidation processes, mechanisms and synergistic antibiotic degradation

Human diseases caused by pathogenic microorganisms make people pay more attention to disinfection. Meanwhile, antibiotics can cause microbial resistance and increase the difficulty of disease treatment, resulting in risk of triggering a vicious circle. Advanced oxidation process (AOPs) has been widely studied in the field of synergistic treatment of the two contaminates. This paper reviews the application of catalytic materials and their modification strategies in the context of AOPs for disinfection and antibiotic degradation. It also delves into the mechanisms of disinfection such as the pathways for microbial inactivation and the related influencing factors, which are essential for understanding the pivotal role of catalytic materials in disinfection principles by AOPs. More importantly, the exploratory research on the combined use of AOPs for disinfection and antibiotic degradation is discussed, and the potential and prospects in this field is highlighted. Finally, the limitations and challenges associated with the application of AOPs in disinfection and antibiotic degradation are summarized. It aims to provide a starting point for future research efforts to facilitate the widespread use of advanced oxidation processes in the field of public health.

Defective ReS2 Triggers High Intrinsic Piezoelectricity for Piezo-Photocatalytic Efficient Sterilization

Rhenium disulfide (ReS2) is a promising piezoelectric catalyst due to its excellent electron transfer ability and abundant unsaturated sites. The 1T' phase structure leads to the evolution of ReS2 into a centrosymmetric spatial structure, which restricts its application in piezoelectric catalysis. Herein, we propose a controllable defect engineering strategy to trigger the piezoelectric response of ReS2. The introduction of vacancy defects disrupts the initial centrosymmetric structure, which breaks the piezoelectric polarization bond and generates piezoelectric properties. By using transmission electron microscopy, we characterized it at the atomic scale and determined that vacancy defects contribute to an excellent piezoelectric property through first-principles calculations. Notably, the piezoelectric coefficient of the catalyst with 40 s-etching (ReS2@C-40) is 23.07 pm/V, an order of magnitude greater than other transition metal dichalcogenides. It demonstrated the feasibility of optimizing piezoelectric properties by increasing the conformational asymmetry. Based on its remarkable piezoelectric activity, ReS2@C-40 exhibits highly efficient piezo-photocatalytic synergistic sterilization performance with 99.99% eradication of Escherichia coli and 96.67% of Staphylococcus aureus within 30 min. This pioneering research on the coupling effect of ReS2 in piezoelectric catalysis and photocatalysis provides ideas for the development of piezo-photocatalysts and efficient water purification technologies.

Efficient Semi-Artificial Photosynthesis of Ethylene by a Self-Assembled InP-Cyanobacterial Biohybrid System

Biomanufacturing of ethylene is particularly important for modern society. Cyanobacterial cells are able to photosynthesize various valuable chemicals. A promising platform for next-generation biomanufacturing, the semiconductor-cyanobacterial hybrid systems are capable of enhancing the solar-to-chemical conversion efficiency. Herein, the native ethylene-producing capability of a filamentous cyanobacterium Nostoc sphaeroides is confirmed experimentally. The self-assembly characteristic of N. sphaeroides is exploited to facilitate its interaction with InP nanomaterial, and the resulting biohybrid system gave rise to further elevated photosynthetic ethylene production. Based on chlorophyll fluorescence measurement and metabolic analysis, the InP nanomaterial-augmented photosystem I activity and enhanced ethylene production metabolism of biohybrid cells are confirmed, the mechanism underlying the material-cell energy transduction as well as nanomaterial-modulated photosynthetic light and dark reactions are established. This work not only demonstrates the potential application of semiconductor-N. sphaeroides biohybrid system as a good platform for sustainable ethylene production but also provides an important reference for future studies to construct and optimize nano-cell biohybrid systems for efficient solar-driven valuable chemical production.

Antibacterial Activity and the Mechanism of the Z-Scheme Bi2MoO6/Bi5O7I Heterojunction under Visible Light

Z-scheme Bi2MoO6/Bi5O7I heterojunction was constructed by an in situ solvothermal method, which was composed of Bi2MoO6 nanosheets growing on the surface of Bi5O7I microrods. The antibacterial activities under illumination towards Escherichia coli (E. coli) were investigated. The Bi2MoO6/Bi5O7I composites exhibited more outstanding antibacterial performance than pure Bi2MoO6 and Bi5O7I, and the E. coli (108 cfu/mL) was completely inactivated by BM/BI-3 under 90 min irradiation. Additionally, the experiment of adding scavengers revealed that h+, •O2- and •OH played an important role in the E. coli inactivation process. The E. coli cell membrane was damaged by the oxidation of h+, •O2- and •OH, and the intracellular components (K+, DNA) subsequently released, which ultimately triggered the apoptosis of the E. coli cell. The enhanced antibacterial performance of Bi2MoO6/Bi5O7I heterojunction is due to the formation of Z-scheme heterojunction with the effective charge transfer via the well-contacted interface of Bi2MoO6 and Bi5O7I. This study provides useful guidance on how to construct Bi5O7I-based heterojunction for water disinfection with abundant solar energy.

Modulation of ultrathin nanosheet structure and nitrogen defects in graphitic carbon nitride for efficient photocatalytic bacterial inactivation

The efficient generation and utilization of ROSs is a key step in determining the achievement of safe drinking water by photocatalytic bacterial inactivation technology. Although graphitic carbon nitride (g-C3N4) serves as a green and promising photocatalyst for water disinfection, insufficient bacterial capturing capacity and serious charge recombination of pristine g-C3N4 extremely restrict its bactericidal activity. Herein, we develop a facile thermal exfoliation and thermal polymerization method to prepare the nitrogen-defective ultrathin g-C3N4 nanosheets (DUCN-500). Our results showed that ultrathin nanosheet structure greatly enhanced bacterial capturing capacity of g-C3N4 to increase the utilization efficiency of ROS, which contributed to the performance of DUCN-500 greatly outperforming bulk g-C3N4. The nitrogen defects increased ROS generation (·O2- and H2O2) by approximately 4.6 times, which was attributed to negative shift of the conduction band potential and rapid separation of charge carriers. The DUCN-500 could rapidly and completely inactivate Escherichia coli and Bacillus subtilis in real sewage under simulated solar irradiation, accompanied by good anti-interference capability and stability. Additionally, bacterial morphology destruction, the loss of antioxidant enzyme activity and the leakage of protein were proven to be the main mechanisms of photocatalytic sterilization. This study offers new insight into the rational design of efficient g-C3N4-based photocatalysts for water disinfection.

Molecularly imprinted polymers based on calcined rape pollen and deep eutectic solvents for efficient sinapic acid extraction from rapeseed meal extract

Substances that possess hierarchical and interconnected porous features are ideal choices for acting as skeletons to synthesize surface molecularly imprinted polymers (MIPs). In this work, rape pollen, a waste of biological resources, was calcined and a porous mesh material with a high specific surface area was obtained. The cellular material was adopted as a supporting skeleton to synthesize high-performance MIPs (CRPD-MIPs). The CRPD-MIPs presented an ultrathin imprinted layered structure, with an enhanced adsorption capacity for sinapic acid (154 mg g^-1) relative to the non-imprinted polymers. The CRPD-MIPs also exhibited good selectivity (IF = 3.24) and a fast kinetic adsorption equilibrium (60 min). This method exhibited a good linear relationship (R2 = 0.9918) from 0.9440 to 29.26 μg mL^-1, and the relative recoveries were 87.1-92.3%. The proposed CRPD-MIPs based on hierarchical and interconnected porous calcined rape pollen may be a valid program for the selective extraction of a particular ingredient from complicated actual samples.

Influence of CoOx surface passivation and Sn/Zr-co-doping on the photocatalytic activity of Fe2O3 nanorod photocatalysts for bacterial inactivation and photo-Fenton degradation

Hydrothermal and wet impregnation methods are presented in this study for synthesizing CoO_x(1 wt%)/Sn-Zr codoped-Fe₂O₃ nanorod photocatalysts for the degradation of organic pollutants and deactivation of bacteria. A hydrothermal route was used to synthesize self-assembled rod-like hierarchical structures of Sn(0-6%) doped Zr-Fe₂O₃ NRs. Additionally, a wet impregnation method was used to load CoO_x onto the surface of photocatalysts (Sn(0-6%)-doped Zr-Fe₂O₃ NRs). A series of 1 wt% CoO_x modified Sn(0-6%)-doped Zr-Fe₂O₃ NRs were synthesized, characterized, and utilized for the photocatalytic decomposition of organic contaminants, along with the killing of E. coli and S. aureus. In comparison with 0, 2, and 6% Sn co-doped Zr-Fe₂O₃ NRs, the CoO_x(1 wt%)/4%Sn/Zr-Fe₂O₃ NRs photocatalyst exhibited an E. coli and S. aureus inactivation efficiencies (90 and 98%). A bio-TEM study of treated and untreated bacterial cells revealed that the CoO_x(1 wt%)/4%Sn/Zr-Fe₂O₃ NRs photocatalyst led to considerable changes in the bacterial cell membranes' morphology. The optimal CoO_x(1 wt%)/Sn(4%) co-doped Zr-Fe₂O₃ NRs photocatalyst achieved degradation efficiencies of 98.5% and 94.6% for BPA and orange II dye. As a result, this work will provide a facile and effective method for developing visible light-active photocatalysts for bacterial inactivation and organic pollutants degradation.

Liquid exfoliation of bulk g-C3N5 to nanosheets for improved photocatalytic antibacterial activity

Liquid exfoliation of bulk g-C₃N₅ was applied to synthesize g-C₃N₅ nanosheets. In order to characterize the samples, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectra (XPS), UV-Vis absorption spectra (UV-Vis), and photoluminescence spectra (PL) were examined. g-C₃N₅ nanosheets exhibited enhanced performance in the inactivation of Escherichia coli (E. coli) with visible light irradiation relative to bulk g-C₃N₅ and promoted complete inactivation of E. coli within 120 min. h⁺ and •O₂^- were the principal reactive species in the antibacterial process. In the early stages, SOD and CAT played a defensive role in resisting oxidative damage of active species. With the prolonged light exposure time, the antioxidant protection system was overwhelmed leading to the destruction of the cell membrane. The leakage of cell contents such as K⁺, protein, and DNA caused bacterial apoptosis ultimately. The enhanced photocatalytic antibacterial performance of g-C₃N₅ nanosheets is ascribed to the stronger redox property by the upward shift of CB and downward shift of VB compared with bulk g-C₃N₅. On the other hand, larger specific surface area and better separation efficiency of photoinduced carriers are helpful to the improved photocatalytic performance. This study systematically revealed the inactivation process toward E. coli and expanded the application range of g-C₃N₅-based materials with abundant solar energy.

Extraordinary microcarriers derived from spores and pollens

Spores and pollens refer to the reproductive cells of seed plants and asexually reproducing sporophytes, exhibiting a natural core-shell structure and exquisite surface morphology. They possess extraordinary dimensional homogeneity, porosity, amphiphilicity and adhesion. Their sporopollenin exine layer endows them with chemically stable, UV resistant, and biocompatible properties, which can also be facilely functionalized due to sufficient groups on the surface. The unique characteristics of spores and pollens have facilitated a wide range of applications in drug carriers, biological imaging, food science, microrobotics, environmental purification, flexible electronics, cell scaffolds, 3D printing materials and biological detection. This review showcases the common structural composition and physicochemical properties of spores and pollens, describes the extraction and processing methods, and summarizes the recent research on their applications in various fields. Following these sections, this review analyzes the existing challenges in spores and pollen research and provides a future outlook.

Construction of S-Scheme CuS/Bi5O7I Heterojunction for Boosted Photocatalytic Disinfection with Visible Light Exposure

In this paper, a novel S-scheme CuS/Bi5O7I heterojunction was successfully constructed using a two-step approach comprising the alkaline hydrothermal method and the adsorption–deposition method, and it consisted of Bi5O7I microrods with CuS particles covering the surface. The photocatalytic antibacterial effects on Escherichia coli (E. coli) were systematically examined with visible light exposure. The results suggested that the 3%-CuS/Bi5O7I composite showed the optimal antibacterial activity, completely inactivating E. coli (5 × 108 cfu/mL) in 180 min of irradiation. Moreover, the bacterial inactivation process was scientifically described. •O2− and h+ were the major active species for the inactivation of the bacteria. In the early stages, SOD and CAT initiated the protection system to avoid the oxidative destruction of the active species. Unfortunately, the antioxidant protection system was overwhelmed thereafter, which led to the destruction of the cell membrane, as evidenced by the microstructure changes in E. coli cells. Subsequently, the leakage of intracellular components including K+, proteins, and DNA resulted in the unavoidable death of E. coli. Due to the construction of the S-scheme heterojunction, the CuS/Bi5O7I composite displayed the boosted visible light harvesting, the high-efficiency separation of photogenerated electrons and holes, and a great redox capacity, contributing to an outstanding photocatalytic disinfection performance. This work offers a new opportunity for S-scheme Bi5O7I-based heterojunctions with potential application in water disinfection.

Synthesis of Rape Pollen-Fe2O3 Biohybrid Catalyst and Its Application on Photocatalytic Degradation and Antibacterial Properties

The efficient biohybrid photocatalysts were prepared with different weight ratios of Fe2O3 and treated rape pollen (TRP). The synthesized samples were characterized by different analytical techniques. The results showed that carbonized rape pollen had a three-dimensional skeleton and granular Fe2O3 uniformly covered the surface of TRP. The Fe2O3/TRP samples were used for degradation of Methylene Blue (MB) and Escherichia Coli (E. coli) disinfection in water under visible light. The degradation of MB and inactivation of E. coli was achieved to 93.7% in 300 min and 99.14% in 100 min, respectively. We also explored the mechanism during the reaction process, where reactive oxygen species (ROS) including hydroxyl radicals and superoxide radicals play a major role throughout the reaction process. This work provides new ideas for the preparation of high-performance photocatalysts by combining semiconductors with earth-abundant biomaterials.

Oxygen vacancy mediated α-MoO3 bactericidal nanocatalyst in the dark: Surface structure dependent superoxide generation and antibacterial mechanisms

Understanding bacteria inactivation mechanisms of nanomaterials on the surface molecular level is of prime importance for the development of antibacterial materials and their application in restraining the transmission of pathogenic microorganisms. This study prepared an oxygen vacancy-mediated bactericidal nanocatalyst α-MoO₃ which exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus in the dark. By manipulating the surface structure of α-MoO₃, the facile tuning of superoxide radical (•O₂^-) generation can be achieved, which was confirmed by electron paramagnetic resonance. •O₂^- disrupted bacterial membrane through attacking lipopolysaccharide (LPS) and phosphatidylethanolamine (PE). Intracellular reactive oxygen species (ROS) experiments confirm that oxidative stress induced by •O₂^- also played a vital role in bacterial inactivation, which might account for DNA damage verified by comet assays. The α-MoO₃ with rich oxygen vacancies also exhibited good antibacterial efficiency (＞99.00 %) toward airborne microbes under dark conditions, indicating its potential to impede the transmission of pathogenic microbes.

Advanced photocatalytic sterilization for recalcitrant Enterococcus sp. contaminated water by newly developed Z-scheme Bi2WO6 based composites under solar light

Pathogenic contamination is one of the major causes of clean water shortage, which poses great risk to human health. Herein, g-C₃N₄ (CN) was firstly introduced to Ag/Ag₂O/BiPO₄/Bi₂WO₆ (Ag/P/BWO) to construct a novel Z-scheme composite CN-Ag/P/BWO for disinfecting Enterococcus sp. contaminated water. CN-Ag/P/BWO showed excellent disinfection performance toward recalcitrant Enterococcus sp. under simulated solar light irradiation, achieving complete inactivation of 1.5 × 10⁷ cfu mL^-1 of bacterial cells only within 60 min, which was mainly attributed to the improved light absorption ability, charge carries separation/transfer efficiency and surface wettability. Additionally, the disinfection mechanism of CN-Ag/P/BWO toward Enterococcus sp. was systematically investigated. Photogenerated active species h⁺, ·OH and ·O₂^- worked together and played crucial roles in photocatalytic inactivation. The antioxidant system enabled Enterococcus sp. self-protection ability at the beginning of disinfection through secreting more antioxidant enzymes. However, with accumulation of active species, bacterial cell membrane and energy system were damaged, which further led to leakage of intracellular components and decomposition of bacteria. Besides, CN-Ag/P/BWO exhibited high practicability for different environmental factors and also performed well for real lake water disinfection. The high stability further confirmed its practicability for water disinfection. This work not only systematically revealed the disinfection mechanism toward Enterococcus sp., but also provided an efficient method for water disinfection.

Efficient Near-Infrared Response Antibacterial Ceramics Based on the Method of Facile In Situ Etching Upconversion Glass-Ceramics

As the world is faced with the coronavirus disease 2019 (COVID-19) pandemic, photocatalytic antibacterial ceramics can reduce the consumption of disinfectants and improve the safety of the public health environment. However, these antibacterial ceramics are often limited by poor stability and low light utilization efficiency. Herein, an antibacterial ceramic was developed via the method of facile in situ etching of upconversion glass-ceramics (UGC) (FIEG) with HCl, in which the BiOCl nanosheets were in situ grown on the surface of GC to improve its stability and antibacterial activity. The results suggest that the upconversion antibacterial ceramics can harvest and utilize near-infrared (NIR) photons efficiently, which display notable antibacterial activity for Escherichia coli (E. coli) under NIR (≥780 nm) and visible light (420-780 nm) irradiation, with a maximum inactivation rate of 7.5 log in 30 min. Meanwhile, in the cycle experiment, more than 6 log inactivation of E. coli was achieved using an antibacterial ceramic sheet after 2-h NIR light irradiation, and the stability of the antibacterial ceramic was discussed. Furthermore, the reactive species, fluorescence-based live/dead cells, and cell structure of bacteria were analyzed to verify the antibacterial mechanism. This study provides a promising strategy for the construction of efficient and stable antibacterial ceramics.

Boosting the photocatalytic performance of Bi2Fe4O9 through formation of Z-scheme heterostructure with In2S3: Applications towards water decontamination

Design of biocompatible nano-heterostructure photocatalyst with broad UV-visible spectrum response and strong redox ability is a promising approach with potential application in micropollutant degradation and pathogen deactivation from aqueous sources. Herein, we have reported the facile fabrication of In₂S₃/Bi₂Fe₄O₉ (ISxBFO) binary heterostructure by hydrothermally depositing In₂S₃ nanoparticles (20-40 nm) over Bi₂Fe₄O₉ nanocuboids/nanoplates prepared by combustion synthesis route. In depth characterization study revealed broad spectrum UV-Vis absorption, large interfacial contact, improved charge carrier separation and mobility and a longer excited state life time (4.7 ns) for the ISxBFO heterostructure materials. The integration of In₂S₃ with Bi₂Fe₄O₉ strongly boosts the optoelectrical and photocatalytic property of pristine Bi₂Fe₄O₉. The ISxBFO heterostructure material exhibited enhanced photocatalytic efficiency for aqueous phase degradation of sulfamethoxazole antibiotics (k_app = 0.06 min^-1) and phenyl urea herbicides (k_app = 0.028 min^-1) with reaction rates 3-8 times higher than the pure BFO component. The MTT assay experiments confirmed non-cytotoxic nature of treated sulfamethoxazole and diuron solutions. The composite materials also displayed convincing antibacterial behavior towards toxigenic Vibrio cholerae pathogen. Haemagglutination assay study revealed excellent biocompatibility of the binary composite up to 200 mg L^-1. Radical trapping study suggested expeditious generation of ^•OH and ^•O₂^- radicals over the ISxBFO surface which is nearly 3.8 and 2.3 times higher than pure BFO and In₂S₃ respectively. The occurrence of a direct Z-scheme mechanism is inferred from radical trapping and XPS study which accounted for the improved photocatalytic activity and strong radical generation property of the ISxBFO heterostructure material.

Nanomaterial-enabled photothermal-based solar water disinfection processes: Fundamentals, recent advances, and mechanisms

The pathogenic microorganisms in water pose a great threat to human health. Photothermal and photothermocatalytic disinfection using nanomaterials (NPs) has offered a promising and effective strategy to address the challenges in solar water disinfection (SODIS), especially in the point-of-use operations. This review aims at providing comprehensive and state-of-the-art knowledge of photothermal-based disinfection by NPs. The fundamentals and principles of photothermal-based disinfection were first introduced. Then, recent advances in developing photothermal/photothermocatalytic catalysts were systematically summarized. The light-to-heat conversion and disinfection performance of a large variety of photothermal materials were presented. Given the complicated mechanisms of photothermal-based disinfection, the attacks from reactive oxygen species and heat, the destruction of bacterial cells, and the antibacterial effects of released metal ions were highlighted. Finally, future challenges and opportunities associated with the development of cost-effective photothermal/photothermocatalytic disinfection systems were outlined. This review will provide guidance in designing future NPs and inspire more research efforts from environmental nano-communities to move towards practical water disinfection operations.

Chronic level of exposures to low-dosed MoS2 nanomaterials exhibits more toxic effects in HaCaT keratinocytes

Molybdenum disulfide nanomaterials (MoS₂ NMs) have shown significant role as photocatalysts, lubricating agents and sterilant due to their remarkable physicochemical properties. Because of the increasing demand for MoS₂ NMs in numerous industrial domains, greater occupational exposure and subsequent NMs release into environment would be unavoidable. However, much efforts have been made to uncover the biological effects of NMs at unrealistic high concentration or acute duration, placing constraints on setting the realistic occupational exposure thresholds with confidence. In order to fill the current knowledge gap, this study aimed to evaluate the nanotoxicity of MoS₂ NMs with or without surface defects under the more realistic exposure mode. Noteworthily, the artificial sweat transformed-occupational exposure-cytotoxicity investigation of MoS₂ NMs was established as the main studied line. And the high cellular internalization and augmented oxidative stress triggered by surface defect could be recognized as the main factors for triggering serious cellular damage. Moreover, the HaCaTs exhibited loss of cell membrane integrity, dysfunction of mitochondria, disorder of endoplasmic reticulum and damages of nuclei after chronic exposure, compared with acute exposure. The study provided closely realistic exposure scenarios for NMs which exhibited significant difference from acute toxic investigation, enriching understanding towards real environmental safety of NMs.

Bacterial Inactivation and Biofilm Disruption through Indigenous Prophage Activation Using Low-Intensity Cold Atmospheric Plasma

Biofilms can be pervasive and problematic in water treatment and distribution systems but are difficult to eradicate due to hindered penetration of antimicrobial chemicals. Here, we demonstrate that indigenous prophages activated by low-intensity plasma have the potential for efficient bacterial inactivation and biofilm disruption. Specifically, low-intensity plasma treatment (i.e., 35.20 W) elevated the intracellular oxidative reactive species (ROS) levels by 184%, resulting in the activation of prophage lambda (λ) within antibiotic-resistant Escherichia coli K-12 (lambda+) [E. coli (λ+)]. The phage activation efficiency was 6.50-fold higher than the conventional mitomycin C induction. Following a cascading effect, the activated phages were released upon the lysis of E. coli (λ+), which propagated further and lysed phage-susceptible E. coli K-12 (lambda-) [E. coli (λ-)] within the biofilm. Bacterial intracellular ROS analysis and ROS scavenger tests revealed the importance of plasma-generated ROS (e.g., ^•OH, ¹O₂, and ^•O₂^-) and associated intracellular oxidative stress on prophage activation. In a mixed-species biofilm on a permeable membrane surface, our "inside-out" strategy could inactivate total bacteria by 49% and increase the membrane flux by 4.33-fold. Furthermore, the metagenomic analysis revealed that the decrease in bacterial abundance was closely associated with the increase in phage levels. As a proof-of-concept, this is the first demonstration of indigenous prophage activations by low-intensity plasma for antibiotic-resistant bacterial inactivation and biofilm eradication, which opens up a new avenue for managing associated microbial problems.

Anaerobic self-assembly of a regenerable bacteria-quantum dot hybrid for solar hydrogen production

Inorganic-biological hybrid systems (bio-hybrids), comprising fermentative bacteria and inorganic semiconductor photosensitizers for synergistic utilization of solar energy and organic wastes, offer opportunities for sustainable fuel biosynthesis, but the low quantum efficiency, photosensitizer biotoxicity and inability for self-regeneration are remaining hurdles to practical application. Here, we unveil a previously neglected role of oxygen in suppressing the biosynthesis of cadmium selenide quantum dots (CdSe QDs) and the metabolic activities of Escherichia coli, and accordingly propose a simple oxygen-regulation strategy to enable the self-assembly of bacterial-QD hybrids for efficient solar hydrogen production. Shifting from aerobic to anaerobic biosynthesis significantly lowered the intracellular reactive oxygen species level and increased NADPH and thiol-protein production, enabling a two-order-of-magnitude higher bio-QD synthesis rate and resulting in CdSe-rich products. Bacteria with abundant biocompatible intracellular bio-QDs naturally formed a highly active and self-regenerable bio-hybrid and achieved a quantum efficiency of 28.7% for hydrogen production under visible light, outperforming all the existing bio-hybrids. It also exhibited high stability during cyclic operation and robust performance for treating real wastewater under simulated sunlight. Our work provides valuable new insights into the metallic nanomaterial biosynthesis process to guide the design of self-assembled bio-hybrids towards sustainable energy and environmental applications.

A modified flower pollen-based photothermocatalytic process for enhanced solar water disinfection: Photoelectric effect and bactericidal mechanisms

Solar disinfection (SODIS) is regarded as an affordable and effective point-of-use (POU) water disinfection treatment urgently needed in rural developing world. This work developed an enhanced SODIS scheme that utilized a novel flower pollen-based catalyst (Te-TRP). The bench-scale experiments demonstrated 100% photothermocatalytic inactivation of approximately 7-log E. coli K-12, Spingopyxis sp. BM1-1, or S. aureus bacterium by Te-TRP within 40-60 min. Moving toward practical device design, we constructed a flow-through reactor and demonstrated the outstanding water disinfection performance of Te-TRP. The in-depth mechanistic study revealed the synergetic effect between photocatalysis and photothermal conversion and identified the bacterial inactivation pathway. ¹O₂ and ·O₂^¯ were verified to be the dominant reactive oxygen species involved in the bacterial inactivation. The damage to bacterial cells caused by photothermocatalytic reactions was systematically investigated, demonstrating the cell membrane destruction, the loss of enzyme activity, the increased cell membrane permeability, and the complete inactivation of bacteria without the viable but nonculturable state cells. This work not only affords a facile approach to preparing biomaterial-based catalysts capable of efficient photothermocatalytic bacterial inactivation, but also proposes a prototype of POU water treatment, opening up an avenue for sustainable environmental remediation.

Vacancy-rich BiO2-x as a highly-efficient persulfate activator under near infrared irradiation for bacterial inactivation and mechanism study

This study, for the first time, developed a novel defective BiO_2-x based collaborating system, where the near-infrared light (NIR) irradiation (λ > 700 nm) initiated persulfate activation and photocatalytic bacterial inactivation simultaneously. Vacancy-rich BiO_2-x nanoplates possessed impressive NIR absorption and firstly realized persulfate activation under NIR irradiation. In this collaborating system, on one hand, the persulfate can be transformed into sulfate radicals through light/heat activation mode directly, which would be enhanced by the presence of vacancy-rich BiO_2-x owing to its outstanding light and heat absorption ability. On the other hand, the photogenerated electrons can further efficiently react with persulfate and form sufficient reactive sulfate radicals. The sulfate radicals, synergizing with other reactive species (O₂^-, h⁺, etc.), achieved a 7-log Escherichia coli inactivation within 40 min. The systematic investigation of inactivation mechanism revealed that the reactive species caused the dysfunction of cellular respiration, ATP synthesis and bacterial membrane, followed by the severely oxidative damage to the antioxidative SOD and CAT enzymes and the generation of carbonylated protein. The final leakage of DNA and RNA implied the lethal damage to the bacteria cells. This work provided a new insight into the persulfate associated NIR driven remediation technology of controlling microbial contaminants.

Self-replicating Biophotoelectrochemistry System for Sustainable CO Methanation

Efficient conversion of CO-rich gas to methane (CH₄) provides an effective energy solution by taking advantage of existing natural gas infrastructures. However, traditional chemical and biological conversions face different challenges. Herein, an innovative biophotoelectrochemistry (BPEC) system using Methanosarcina barkeri-CdS as a biohybrid catalyst was successfully employed for CO methanation. Compared with CO₂-fed BPEC, BPEC-CO significantly extended the CH₄ producing time by 1.7-fold and exhibited a higher CH₄ yield by 9.5-fold under light irradiation. This superior conversion of CO resulted from the fact that CO could serve as an effective quencher of reactive species along with the photoelectron production. In addition, CO was used as a carbon source either directly or indirectly via the produced CO₂ for M. barkeri. Such a process improved the redox activities of membrane-bound proteins for BPEC methanogenesis. These results were consistent with the transcriptomic analyses, in which the genes for the putative CO oxidation and CO₂ reduction pathways in M. barkeri were highly expressed, while the gene expression for reactive oxygen species detoxification remained relatively stable under light irradiation. This study has provided the first proof-of-concept evidence for sustainable CO methanation under a mild condition in the self-replicating BPEC system.

The Microbial Mechanisms of a Novel Photosensitive Material (Treated Rape Pollen) in Anti-Biofilm Process under Marine Environment

Marine biofouling is a worldwide problem in coastal areas and affects the maritime industry primarily by attachment of fouling organisms to solid immersed surfaces. Biofilm formation by microbes is the main cause of biofouling. Currently, application of antibacterial materials is an important strategy for preventing bacterial colonization and biofilm formation. A natural three-dimensional carbon skeleton material, TRP (treated rape pollen), attracted our attention owing to its visible-light-driven photocatalytic disinfection property. Based on this, we hypothesized that TRP, which is eco-friendly, would show antifouling performance and could be used for marine antifouling. We then assessed its physiochemical characteristics, oxidant potential, and antifouling ability. The results showed that TRP had excellent photosensitivity and oxidant ability, as well as strong anti-bacterial colonization capability under light-driven conditions. Confocal laser scanning microscopy showed that TRP could disperse pre-established biofilms on stainless steel surfaces in natural seawater. The biodiversity and taxonomic composition of biofilms were significantly altered by TRP (p < 0.05). Moreover, metagenomics analysis showed that functional classes involved in the antioxidant system, environmental stress, glucose−lipid metabolism, and membrane-associated functions were changed after TRP exposure. Co-occurrence model analysis further revealed that TRP markedly increased the complexity of the biofilm microbial network under light irradiation. Taken together, these results demonstrate that TRP with light irradiation can inhibit bacterial colonization and prevent initial biofilm formation. Thus, TRP is a potential nature-based green material for marine antifouling.

Near-infrared responsive sulfur vacancy-rich CuS nanosheets for efficient antibacterial activity via synergistic photothermal and photodynamic pathways

Defect engineering has been proven to be an effective approach for electronic structure modulation and plays an important role in the photocatalytic performance of nanomaterials. In this study, a series of CuS nanosheet sulfur vacancies (V_S) are constructed by a simple hydrothermal synthesis method. The CuS with the highest V_S concentration exhibits strong antibacterial performance, achieving bactericidal rates of 99.9% against the Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacteria under 808 nm laser irradiation. Under illumination, the temperature of the catalyst increases from 23.5 °C to 53.3 °C, and with a high photothermal conversion efficiency of 41.8%. For E. coli and B. subtilis, the reactive oxygen species (ROS) production that is induced by the CuS group is 8.6 and 9.6 times greater, respectively, than that of the control group. The presence of V_S facilitates the enhancement of the light absorption capacity and the separation efficiency of electron-hole pairs, thereby resulting in improved photocatalytic performance. The synergistic effect of photothermal therapy (PTT) and photodynamic therapy (PDT) is aimed at causing oxidative damage and leading to bacterial death. Our findings provide an effective antibacterial strategy and offer new horizons for the application of CuS catalysts with V_S in the NIR region.

A biological nanofoam: The wall of coniferous bisaccate pollen

The outer layer of the pollen grain, the exine, plays a key role in the survival of terrestrial plant life. However, the exine structure in different groups of plants remains enigmatic. Here, modern and fossil coniferous bisaccate pollen were examined to investigate the detailed three-dimensional structure and properties of the pollen wall. X-ray nanotomography and volume electron microscopy are used to provide high-resolution imagery, revealing a solid nanofoam structure. Atomic force microscopy measurements were used to compare the pollen wall with other natural and synthetic foams and to demonstrate that the mechanical properties of the wall in this type of pollen are retained for millions of years in fossil specimens. The microscopic structure of this robust biological material has potential applications in materials sciences and also contributes to our understanding of the evolutionary success of conifers and other plants over geological time.

Recent advances in photocatalytic removal of airborne pathogens in air

The abatement of airborne pathogens such as bacteria, viruses, and fungi has become an important goal of air-quality management. Efficient and effective treatment techniques such as photocatalysis are essential for disinfection of airborne microorganisms. This review focuses on recent advances in the formulation and development of photocatalytic disinfection, design of efficient photocatalysts, choice of photocatalytic reactor, removal and/or disinfection mechanisms, and the role of reactive ion species. Data from recent studies are analyzed to accurately assess the efficacy of such disinfection approaches. This review also highlights the application of innovative materials in individual and combined abatement systems against airborne bacterial, viral, and fungal pathogens. We discuss the efficiency and benefits presented by such systems, address the challenges, and provide a perspective for future research.

The synergistic effect of enhanced photocatalytic activity and photothermal effect of oxygen-deficient Ni/reduced graphene oxide nanocomposite for rapid disinfection under near-infrared irradiation

The rational design of high antibacterial efficiency are urgently needed as the occurrence of drug-resistance issues. Hence, Ni/reduced graphene oxide nanocomposite (Ni/rGO) with different amounts of oxygen vacancies were fabricated for efficient disinfection. The optimized Ni/rGO (A100) exhibited highly effective inactivation efficacy of 99.6% and 99.5% against Escherichia coli and Bacillus subtilis within 8 min near-infrared (NIR) irradiation through the synergistic effects of photothermal therapy and oxidative damage, which were much higher than single treatment. The A100 nanocomposite achieved an extraordinary photothermal conversion efficiency (35.78%) under the 808 nm irradiation for enhanced photothermal hyperthermia, thereby destroying the cell membrane and accelerating the GSH depletion. The radical scavenger experiment confirmed that •O₂^- and •OH play the chief role in photodisinfection reaction. Besides, A100 could exert significant damage on the ATP synthesis. The excellent photothermal performance and photocatalytic activity can be attributed to the appropriate oxygen vacancy density, which improves the absorption of NIR light and facilitates the separation of photogenerated electron-hole pairs. Besides, the higher NiO content of A100 contributed to improving the photocatalytic effect. Our work demonstrated a promising strategy for efficient water pollution purification caused by pathogenic bacteria.

Adsorption and visible-light photocatalytic degradation of organic pollutants by functionalized biochar: Role of iodine doping and reactive species

Here we developed the functionalized biochar as low-cost and heavy metal-free photocatalysts via a facile iodine doping method, which exhibit efficient adsorption and visible-light-driven photocatalytic degradation of representative organic pollutants, phenol and tetracycline. On one hand, iodine doping elevates the adsorption via creating extra pores, e.g., the adsorbed amounts of phenol by iodine-doped WSP and OSR biochar are increased by 161.8% and 146.3%, respectively, which in turn facilitates the photocatalytic oxidation of the adsorbed pollutants. On the other hand, iodine doping leads to the strong photo-induced excitation and remarkably reduced charge carrier transfer resistance, boosting the photocatalytic activity of iodine-doped biochar by more than 20 orders towards organic pollutants (e.g., phenol) degradation. The systematic analysis of reactive species reveals the active roles of O₂^-, H₂O₂, ¹O₂, OH, electrons, and holes in photocatalytic process and identifies O₂^- to be the major contributor. This work affords a facile approach to generating porous and visible-light-driven photocatalyst from biomass for efficient adsorbing and degrading organic pollutants, opening up an avenue to turn biowaste into biomaterials for sustainable environmental remediation.

Recent advances of monoelemental 2D materials for photocatalytic applications

As a sustainable environmental governance strategy and energy conversion method, photocatalysis has considered to have great potential in this field due to its excellent optical properties and has become one of the most attractive technologies today. Among 2D materials, the emerging two-dimensional (2D) monoelemental materials mainly distributed in the -IIIA, -IVA, -VA and -VIA groups and show excellent performance in solar energy conversion due to their graphene-like 2D atomic structure and unique properties, thereby drawing increasing attention. This review briefly summarizes the preparation processes and fundamental properties of 2D single-element nanomaterials, as well as various modification strategies and adjustment mechanisms to enhance their photocatalytic properties. In particular, this article comprehensively discusses the related practical applications of 2D single-element materials in the field of photocatalysis, including photocatalytic degradation for contaminants removal, photocatalytic pathogen inactivation, photocatalytic fouling control and photocatalytic energy conversion. This review will provide some new opportunities for the rational design of other excellent photocatalysts based on 2D monoelemental materials, as well as present tremendous novel ideas for 2D monoelemental materials in other environmental conservation and energy-related applications, such as supercapacitors, electrocatalysis, solar cells, and so on.

The effect of hybrid zinc oxide/graphene oxide (ZnO/GO) nano-catalysts on the photocatalytic degradation of simazine

The photocatalytic degradation of simazine (SIM) was investigated using zinc oxide/graphene oxide (ZnO/GO) composite materials under visible light irradiation. The reaction kinetics was studied to optimize the reaction parameters for efficient degradation of SIM. Batch studies were performed to investigate the effects of initial reaction pH, the loading of the ZnO onto GO, and mass of catalyst on the removal of SIM from aqueous solution. A pH of 2 was determined to be the optimal reaction pH for the different ZnO-loaded GO catalysts. In addition, a mass of 40 mg of catalyst in the reaction was observed to be the most effective for the catalysts synthesized using 20 and 30 mmol of Zn²⁺ ions; whereas a mass of 10 mg was most effective for the ZnO/GO composite material synthesized using 10 mmol Zn²⁺ ions. The reaction was observed to follow a second-order kinetics for the degradation process. Furthermore, the synthesized ZnO/GO composite catalysts resulted in higher reaction rates than those observed for pure ZnO. The 30 mmol ZnO/GO composite expressed a rate of SIM degradation ten times greater than the rate observed for pure ZnO, and sixty-two times greater than the rate of photolysis. In addition, the catalyst cycling exhibited a constant photocatalytic activity for the ZnO/GO composite over three reaction cycles without the need of a conditioning cycle.

Visualizing the Interfacial Charge Transfer between Photoactive Microcystis aeruginosa and Hydrogenated TiO2

Exploring photoactive biotic-abiotic conjugations is of great importance for a variety of applications, but it remains difficult to probe the interfacial transfer of photoinduced charge carriers. In this work, Kelvin probe force microscopy, together with fluorescence imaging technique, were used to visually observe the spatial distribution and interfacial behavior of photocarriers in Microcystis aeruginosa/TiO₂ hybrids. Experimental investigations suggested that photosynthetic microalgae cells were prone to trap photoholes from TiO₂ photocatalysts. Oxygen vacancy defects in semiconductor exhibited significant impact on the charge migration, as the surface photovoltage of hydrogenated TiO₂/microalgae hybrid was much higher than the pristine system. Profiting from the bioenhanced charge separation, biotic-abiotic architecture presented remarkably increased activity for photocatalytic inactivation of microalgae microorganisms. This work not only highlights the visual techniques for understanding the charge transfer around biotic-abiotic interface, but also provides a bioenhanced conjugation for the photocatalytic elimination of microorganisms in water treatment applications.