Synthesis of MoS2/g-C3N4 nanocomposites with enhanced visible-light photocatalytic activity for the removal of nitric oxide (NO)

ZnO/g-C3N4 photocatalyst activated by low-pressure ultraviolet for restoring the SWASV signals: A fast pretreatment method for electrochemically detecting Cd2+ and Pb2+ in soil extracts

Soil organic matter (SOM) significantly impacts the detection accuracy of Cd2+ and Pb2+ using square wave anodic stripping voltammetry (SWASV) due to the complexation of SOM to heavy metal ions (HMIs), thereby attenuating SWASV signals. This study explored an effective pretreatment method that combined low-pressure ultraviolet (LPUV) photolysis with the ZnO/g-C3N4 photocatalyst, activating the photocatalyst to generate highly oxidative •OH radicals and O2•- radicals, which effectively disrupted this complexation, consequently restoring the electroactivity of HMIs and achieving high-fidelity SWASV signals. The parameters of the LPUV-ZnO/g-C3N4 photocatalytic system were meticulously optimized, including the pH of photolysis, duration of photolysis, g-C3N4 mass fraction, and concentration of the photocatalyst. Furthermore, the ZnO/g-C3N4 photocatalyst was thoroughly characterized, with an in-depth investigation on the synergistic interaction between ZnO and g-C3N4 and the mechanisms contributing to the restoration of SWASV signals. This synergistic interaction effectively separated charge carriers and reduced charge transfer resistance, enabling photogenerated electrons (e-) from the conduction band of g-C3N4 to be quickly transferred to the conduction band of ZnO, preventing the recombination of e- and h+ and generating more radicals to disrupt complexation and restore the SWASV signals. Finally, the analysis of HMIs in real soil extracts using the proposed pretreatment method demonstrated high detection accuracy of 94.9% for Cd2+ and 99.8% for Pb2+, which validated the feasibility and effectiveness of the proposed method in environmental applications.

Significantly enhanced the light absorption and charge separation of Bi0.5Na0.5TiO3 by coupling with CdS for high-performance piezo-photocatalysis

Sodium bismuth titanate (Bi0.5Na0.5TiO3, BNT) is a typical lead-free piezoelectric material with perovskite structure, which exhibits great potential as piezo-photocatalyst but limited by the little response on visible light and insufficient carriers for efficient catalytic reactions. Herein, a novel BNT/CdS heterojunction was facilely synthesized by the two-step hydrothermal process for significantly enhanced piezo-photocatalytic degradation of organic dyes. The CdS nanoparticles with 35 nm in diameter are uniformly decorated on the highly crystallized BNT spheres. The obtained BNT/CdS heterojunction displays strong absorption of visible light because of the narrow band gap of CdS. Due to the strong built-in electric field under ultrasonic and efficient excitation by visible light, the photogenerated carriers can be efficiently separated at the BNT/CdS interface and migrate to the surface for catalytic reactions. As a result, the BNT/CdS shows much higher piezo-photocatalytic activity than that of BNT and can degrade 99% RhB within 60 min. Meanwhile, the piezo-photocatalytic performance of BNT/CdS is far better than that of individual photocatalysis or piezocatalysis. Moreover, the catalytic experiments in the presence of different scavengers indicate that ·O2- is the predominant active specie. The synthetic process is simple, low-cost, and controllable to produce high-performance BNT/CdS and is believed to show promising application prospect.

Green synthesis of Au@g-C3N4 nanocomposite using Hyssopus officinalis extract and its sensing application for vortioxetine determination

Herein, we introduce a stable and green Au@g-C3N4 nanocomposite as a selective electrochemical sensor for vortioxetine (VOR) determination. The electrochemical behavior of VOR on the developed electrode was investigated through cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and chronoamperometry. The Au@g-C3N4 nanocomposite was thoroughly observed by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and scanning electron microscopy. The Au@g-C3N4 nanocomposite had a higher conductivity and a narrower band gap than pure g-C3N4, causing higher electrochemical activity for VOR detection. Moreover, Au@g-C3N4 on the glassy carbon electrode (Au@g-C3N4/GCE) monitored a low level of VOR with high efficiency and low interference as an environmentally friendly processing approach. Interestingly, the as-fabricated sensor exhibited an ultrahigh selectivity for recognizing VOR with a detection limit (LOD) of 3.2 nM. Furthermore, the developed sensor was applied to determine VOR in pharmaceutical and biological samples, which indicated a high selectivity in the presence of interferences. This study suggests new insights into the phytosynthesis synthesis of nanomaterials with excellent biosensing applications.

Defect mediated visible light induced photocatalytic activity of Co3O4 nanoparticle decorated MoS2 nanoflower: A combined experimental and theoretical study

In this work, Co₃O₄ nanoparticle-decorated MoS₂ (MoS₂@Co₃O₄) hetero-nanoflowers were synthesized by a facile hydrothermal method, and the effect of Co₃O₄ on the morphological, structural, optical, electronic, and photocatalytic properties of MoS₂ was analyzed. The surface morphology of MoS₂ and MoS₂@Co₃O₄ was studied via field emission electron microscopy (FE-SEM) and transmission electron microscopy (TEM), which revealed a strong interaction between the MoS₂ nanoflower and the nanoparticles. The X-ray diffraction pattern showed a decrease in the crystallite sizes from 7.35 nm to 6.26 nm due to the incorporation of Co₃O₄. The UV-Vis spectroscopy of the analysis revealed that the indirect band gap of MoS₂ was reduced from 1.89 eV to 1.65 eV with the incorporation of Co₃O₄ nanoparticles. Density functional theory (DFT) calculations were used to investigate the electronic properties of MoS₂ and MoS₂@Co₃O₄ hetero-nanoflowers, which also showed a reduction in the electronic band gap for the Co₃O₄ nanoparticles that were injected. The presence of defect states was also observed in the electronic property of MoS₂@Co₃O₄. The photocatalytic activity of the prepared composite and nanoflower is studied using an aqueous solution of methylene blue (MB), and the efficiencies are found to be 27.96% for MoS₂ and 78.89% for MoS₂@Co₃O₄. The improved photocatalytic efficiency of MoS₂@Co₃O₄ hetero-nanoflower can be attributed to narrowing the band gap together with the creation of defect states by the injection of nanoparticles that slows down electron-hole recombination rate by trapping charge carrier. The degradation analysis of the composite provides a new route for the purification of polluted water.

Theoretical exploration of the structural, electronic and optical properties of g-C3N4/C3N heterostructures

Integration of graphene-like carbon nitride materials is essential for nanoelectronic applications. Using density-functional theory (DFT), we systematically investigate the structural, electronic and optical properties of a s-triazine-based g-C₃N₄/C₃N heterostructure under different modified conditions. The g-C₃N₄/C₃N van der Waals heterostructure (vdWH) formed has an indirect bandgap with type-II band alignment and the band structures can be tuned from type-II band alignment to type-I band alignment by applying biaxial strains and external electric fields (E_field). Compared to single transition metal (TM) atoms at g-C₃N₄/C₃N surfaces, the TM atoms anchored in the interlayer region exhibit more stability, and the corresponding bandgaps are changed from 0.19 eV to 0.61 eV. In addition, the g-C₃N₄/C₃N heterostructure has a strong absorption coefficient in the ultraviolet-visible light region along the x direction. It is found that compressive strain has a large influence on the absorption coefficient of the g-C₃N₄/C₃N system. With the increased compressive strain, the absorption spectra in the visible light region disappeared. Tensile strain has a slight effect on the absorption range, but causes a red shift of the absorption spectrum. In comparison, the light absorption coefficient of the g-C₃N₄/C₃N system remains almost unchanged under the E_field conditions. In summary, the formation of a s-triazine-based g-C₃N₄/C₃N heterostructure has shown potential for applications in nanoelectronic and optoelectronic devices.

Facile one-step synthesis of PhC2Cu nanowires with enhanced photocatalytic performance

In recent years, the research of phenylethynylcopper (PhC₂Cu) in photocatalysis has attracted immense attention. However, its synthesis requires two steps extending over 9 days. In this paper, the successful preparation of PhC₂Cu nanowires is reported using a highly rapid and facile one-step method directly using copper acetate and phenylacetylene as raw materials and ascorbic acid as reducing agent. The kinetic studies indicated that the synthetic reaction follows a pseudo-second-order equation through electrical conductivity. Comparative studies of the crystal structures, morphologies, and optical properties of PhC₂Cu prepared by the traditional two-step and the current one-step methods were conducted using XRD, SEM, UV-Vis Drs, FT-IR, Raman spectra, and photocurrent. Meanwhile, the PhC₂Cu nanowires exhibited excellent photocatalytic activity to degrade methyl violet (MV) and glyphosate. This facile and rapid method dramatically improves the preparation efficiency of PhC₂Cu, and the obtained PhC₂Cu also shows higher photocatalytic activity. This remarkable progress enables the possibility of large-scale and efficient preparation of PhC₂Cu with high photocatalytic activity, indicating their excellent application prospect in photocatalysis.

Fabrication of Novel g-C3N4@Bi/Bi2O2CO3 Z-Scheme Heterojunction with Meliorated Light Absorption and Efficient Charge Separation for Superior Photocatalytic Performance

Herein, a novel g-C₃N₄@Bi/Bi₂O₂CO₃ Z-scheme heterojunction was synthesized via simple methods. UV/Vis diffuse reflectance spectroscopy (DRS) revealed that the visible light absorption range of heterojunction composites was broadened from 400 nm to 500 nm compared to bare Bi₂O₂CO₃. The XRD, XPS and TEM results demonstrated that metal Bi was introduced into g-C₃N₄@Bi/Bi₂O₂CO₃ composites, and Bi may act as an electronic bridge in the heterojunction. Metal Bi elevated the separation efficiency of carriers, which was demonstrated by photocurrent and photoluminescence. The performance of samples was assessed via the degradation of Rhodamine B (RhB), and the results exhibited that g-C₃N₄@Bi/Bi₂O₂CO₃ possessed notably boosted photocatalytic activity compared with g-C₃N₄, Bi₂O₂CO₃ and other binary composites. The heterojunction photocatalysts possessed good photostability and recyclability in triplicate cycling tests. Radical trapping studies identified that h⁺ and •O₂^- were two primary active species during the degradation reaction. Based on the energy band position and trapping radical experiments, the possible reaction mechanism of the indirect Z-scheme heterojunction was also proposed. This work could provide an effective reference to design and establish a heterojunction for improving the photocatalytic activity of Bi₂O₂CO₃.

Application of 2D Materials for Adsorptive Removal of Air Pollutants

Air pollution is on the priority list of global safety issues, with the concern of fatal environmental and public health deterioration. 2D materials are potential adsorbent materials for environmental decontamination, owing to their high surface area, manageable interlayer binding, large surface-to-volume ratio, specific binding capability, and chemical, thermal, and mechanistic stability. Specifically, graphene oxide and reduced graphene oxide have been attracting attention, taking advantage of their low cost synthesis, excessive oxygen containing surface functionalities, and intrinsic aqueous dispersibility, making them desirable for the development of cost-effective, high performance air filters. Many different material designs have been proposed to expand their filtration capability, including the functionalization and integration with other metals and metal oxides, which act not only as binding agents to the target pollutants but also as antimicrobial agents. This review highlights the advantages and drawbacks of 2D materials for air filtration and summarizes the interrelationships among various strategies and the resultant filtration performance in terms of structural engineering, morphology control, and material compositions. Finally, potential future directions are suggested toward the idealized designs of 2D material based air filters.

Architecture of visible-light induced Z-scheme MoS2/g-C3N4/ZnO ternary photocatalysts for malachite green dye degradation

The synthesis of bilayer heterojunctions has received considerable attention recently. Fabrication of novel bilayer composites is of significant interest to improve their photocatalytic efficiency. In this study, molybdenum disulfide (MoS₂), a layered dichalcogenide material exhibiting unique properties, in combination with graphitic carbon nitride (g-C₃N₄), a carbon-based layered material, was fabricated with small amounts of zinc oxide (ZnO). Three composites, MoS₂/g-C₃N₄, MoS₂/ZnO, and MoS₂/g-C₃N₄/ZnO were prepared via a simple exfoliation method and characterized by various physicochemical methods. The Z-scheme charge transfer mechanism in the prepared ternary composite improves efficiency by inhibiting the recombination rate of electron-hole pairs. It has shown excellent performance in degrading a major water contaminant, malachite green (MG) dye, under visible light irradiation.

Rapid fabrication of MgO@g-C3N4 heterojunctions for photocatalytic nitric oxide removal

Nitric oxide (NO) is an air pollutant impacting the environment, human health, and other biotas. Among the technologies to treat NO pollution, photocatalytic oxidation under visible light is considered an effective means. This study describes photocatalytic oxidation to degrade NO under visible light with the support of a photocatalyst. MgO@g-C₃N₄ heterojunction photocatalysts were synthesized by one-step pyrolysis of MgO and urea at 550 °C for two hours. The photocatalytic NO removal efficiency of the MgO@g-C₃N₄ heterojunctions was significantly improved and reached a maximum value of 75.4% under visible light irradiation. Differential reflectance spectroscopy (DRS) was used to determine the optical properties and bandgap energies of the material. The bandgap of the material decreases with increasing amounts of MgO. The photoluminescence spectra indicate that the recombination of electron-hole pairs is hindered by doping MgO onto g-C₃N₄. Also, NO conversion, DeNOx index, apparent quantum efficiency, trapping tests, and electron spin resonance measurements were carried out to understand the photocatalytic mechanism of the materials. The high reusability of the MgO@g-C₃N₄ heterojunction was shown by a five-cycle recycling test. This study provides a simple way to synthesize photocatalytic heterojunction materials with high reusability and the potential of heterojunction photocatalysts in the field of environmental remediation.

An overview of MXene-Based nanomaterials and their potential applications towards hazardous pollutant adsorption

With the massive development of industrialization, multiple ecological contaminants in gaseous, liquid, and solid forms are vented into habitats, which is currently at the forefront of worldwide attention. Because of the possible damage to public health and eco-diversity, high-efficiency clearance of these environmental contaminants is a serious concern. Improved nanomaterials (NMs) could perform a significant part in the exclusion of contaminants from the atmosphere. MXenes, a class of two-dimensional (2D) compounds that have got tremendous consideration from researchers for a broad array of applications in a variety of industries and are viewed as a potential route for innovative solutions to identify and prevent a variety of obstreperous hazardous pollutants from environmental compartments due to their exceptional innate physicochemical and mechanical features, including high specific surface area, physiological interoperability, sturdy electrodynamics, and elevated wettability. This paper discusses the recent progress in MXene-based nanomaterials' applications such as environmental remediation, with a focus on their adsorption-reduction characteristics. The removal of heavy metals, dyes, and radionuclides by MXenes and MXene-based nanomaterials is depicted in detail, with the adsorption mechanism and regeneration potential highlighted. Finally, suggestions for future research are provided to ensure that MXenes and MXene-based nanomaterials are synthesized and applied more effectively.

Facile synthesis of CoOOH@MXene to activate peroxymonosulfate for efficient degradation of sulfamethoxazole: performance and mechanism investigation

Using MXene as substrate, CoOOH@MXene with different mass content of CoOOH were prepared and used to active peroxymonosulfate (PMS) for the sulfamethoxazole (SMX) degradation. The sample characterizations demonstrated the successful preparation of CoOOH@MXene. CoOOH@MXene possessed much higher BET surface area (183.82 m²/g) than CoOOH (85.36 m²/g) and MXene (6.89 m²/g) due to the good dispersibility of CoOOH particles on MXene. Due to its large surface area, 1.3CoOOH@MXene displayed the best catalytic performance for the degradation of SMX. With 0.2 g/L of 1.3CoOOH@MXene and 0.5 mM of PMS, 20 μM of SMX was completely eliminated in 10 min. The degradation followed pseudo-first-order kinetic model well, with rate constants of 0.33 min^-1 for 1.3CoOOH@MXene and 0.054 min^-1 for CoOOH. Influencing factors of initial pH, catalyst dosage, PMS concentration, SMX concentration, and co-existing anions on SMX degradation were assessed systematically. Recycling tests verified the excellent reusability and stability of the catalyst. Quenching experiments and electron paramagnetic resonance analysis substantiated that ¹O₂ played a leading role. Moreover, the intermediates were identified, and degradation pathways and activation mechanism of CoOOH@MXene for PMS were proposed. This work may highlight the application of MXene with transition metals in PMS activation.

Coupling of Ru nanoclusters decorated mixed-phase (1T and 2H) MoSe2 on biomass-derived carbon substrate for advanced hydrogen evolution reaction

The development of efficient catalysts for hydrogen evolution reaction (HER) from water splitting is one of the most promising strategies to achieve the goal of peak carbon dioxide emissions and carbon neutrality. Herein, Ru nanoclusters decorated MoSe₂ nanosheets supported on a Crepis tectorum fluff biomass-derived hollow carbon tube (Ru-MoSe₂/CMT) are prepared as the HER catalysts in both alkaline and acidic conditions. The Ru modification induces the transformation of MoSe₂ from 2H phase to 1T phase. Benefiting from the strong water dissociation ability of Ru, Ru-MoSe₂/CMT exhibits a low overpotential of 70 mV with a Tafel slope of 39 mV dec^-1 in 1 M KOH. Furthermore, the assembled Ru-MoSe₂/CMT || RuO₂ system with a low cell voltage of 1.54 V at 10 mA cm^-2 exhibits outstanding overall water splitting performance superior to Pt/C || RuO₂ system. The Ru-MoSe₂/CMT || RuO₂ system also achieves the excellent stability of up to 30 h in 1 M KOH. The synergy effect between Ru and MoSe₂, as well as the improved electron transfer kinetics provided by the biomass-derived carbon substrate together contribute to the excellent HER activity of Ru-MoSe₂/CMT.

Preparation of Ag3PO4/α-Fe2O3 hybrid powders and their visible light catalytic performances

The inefficiency of conventional photocatalytic treatment for removing rhodamine B is posing potential risks to ecological environments. Here, we construct a highly efficient photocatalyst consisting of Ag₃PO₄ and α-Fe₂O₃ hybrid powders for the treatment of rhodamine B. Ag₃PO₄ nanoparticles (nanoparticles, about 50 nm) are uniformly dispersed on the surface of α-Fe₂O₃ microcrystals (hexagonal sheet, about 1.5 μm). The Ag₃PO₄-deposited uniformity on the α-Fe₂O₃ surface first increased, then decreased on increasing the hybrid ratio of Ag₃PO₄ to α-Fe₂O₃. When the hybrid ratio of Ag₃PO₄ to α-Fe₂O₃ is 1 : 2, the distribution of Ag₃PO₄ particles on the sheet α-Fe₂O₃ is more uniform with excellent Ag₃PO₄/α-Fe₂O₃ interface performance. The catalytic degradation efficiency of hybrids with the introduction of Ag₃PO₄ nanoparticles on the α-Fe₂O₃ surface reached 95%. More importantly, the hybrid material exhibits superior photocatalytic stability. Ag₃PO₄/α-Fe₂O₃ hybrids have good reusability, and the photocatalytic efficiency could still reach 72% after four reuses. The excellent photocatalytic activity of the as-prepared hybrids can be attributed to the heterostructure between Ag₃PO₄ and α-Fe₂O_3, which can effectively inhibit the photoelectron-hole recombination and broaden the visible light response range.

Biomimetic nitrogen-rich photocatalyst based on cadmium sulfide for photocatalytic hydrogen evolution

A novel N-rich sugarcane-like photocatalyst CdS/C₃N₅ (CCN) was prepared by a thermal polymerization method and tested for generating H₂ and realizing antiphotocorrosive performance. The best photocatalytic H₂ evolution is obtained for a CdS to C₃N₅ mass ratio of 1:1 (CCN3), which is nearly 33 and 3 times higher than that of pure C₃N₅ and CdS, respectively. CCN3 can be used to effectively reduce CdS photocorrosion and increase stability because of its N-rich performance and sugarcane-like structure, which can affect electron transport and enhance the internal binding force, respectively. CCN3 can maintain a high H₂ evolution ability after 5 cycles, while still maintaining the original sugarcane-like shape, which has an anti-photocorrosive ability.

Sulfur/phosphorus doping-mediated morphology transformation of carbon nitride from rods to porous microtubes with superior photocatalytic activity

Hetero-atoms doping or morphology controlling of carbon nitride (g-C₃N₄) can availably regulate its electronic band structure and optimize photocatalytic performance under visible light. Herein, sulful (S), phosphorus (P) co-doped porous carbon nitride microtubes (SPCN) was synthesized by using ammonium dihydrogen phosphate and melamine as precursors, in which ammonium dihydrogen phosphate can not only control the morphology of carbon nitride from nanorods to porous microtubes, but also provide a potential P source for P-doped CN. The prepared SPCN0.1 with the content of 0.1 g ammonium dihydrogen phosphate displayed the highest photocatalytic hydrogen generation rate of 4200.3 µmol g^-1h^-1, which was approximately 25 and 1.6 folds by bulk g-C₃N₄ (CN) and sulphur doped g-C₃N₄ microrods (SCN), respectively. Moreover, the apparent quantum efficiency of HER reached up to 10.3 % at 420 nm. The enhanced photocatalytic performance may be attributed to the synergistic effect of S, P doping and morphology structure of carbon nitride, which effectively accelerated the separation and transfer of photogenerated electron-hole pairs, proved by photoluminescence spectra, time-resolved PL spectra, electrochemical impedance spectrum and transient photocurrent responses. The novel synthetic method described in this paper is an effective approach to regulate the morphology of g-C₃N₄via non-metal doping with superior photocatalytic performance.

Superhydrophobic catalyst-wrapped fibrofelt with anti-moisture, anti-dusting and NH3-SCR properties

In order to overcome the problem of catalyst poisoning, and achieve high-efficient denitration and dust removal integration, new catalyst filters loaded by superhydrophobic MnOx catalysts (SA-MnOx@Filter) were fabricated by waterborne...

Enabling methanol oxidation by interacting hybrid nano system of spinel Co3O4 nanoparticles decorated MXene

For the successful implementation of direct methanol fuel cells in the commercial applications, highly efficient and durable non-noble electrocatalyst based on conducting and stable non-carbonaceous support can be a potential...

Carbon quantum dots sensitized 2D/2D carbon nitride nanosheets/bismuth tungstate for visible light photocatalytic degradation norfloxacin

A novel carbon quantum dots (CQDs) sensitized 2D/2D carbon nitride nanosheets and bismuth tungstate composite (CQD-CNs/BWO) was successfully prepared via the facile hydrothermal method and used for the photocatalytic degradation of norfloxacin (NOR). During 120 min irradiation test, CQD-CNs/BWO exhibited 9 and 1.76 times higher photocatalytic activity than CNs and BWO, respectively. CQDs and constructed 2D/2D structure could not only improve the light harvesting but also promote the generation and separation of electron-holes. The existing inorganic ions in solution (e.g. bicarbonate ions, chlorine ions, and sulfate ions) could inhibit NOR degradation. Based on the electron spin resonance and free radicals inhibition tests, the holes and superoxide radicals rather than hydroxyl radicals were the main reactive species. The intermediates and possible pathways were proposed, and the antibacterial activity of the treated solution after the reaction was evaluated via bacteriostatic tests. The prepared composite material with high photocatalytic activity and stability is potentially effective for the degradation of antibiotics in wastewater.

Recent advances in g-C3N4 based gas sensors for the detection of toxic and flammable gases: a review

In recent years, many 2D nanomaterials like graphene, MoS2, phosphorene, and metal oxide nanosheets have been investigated for gas sensing applications due to their excellent properties. Amongst other 2D nanomaterials, graphitic carbon nitride (g-C3N4) has attracted significant attention owing to its simple synthesis process, tunable electronic properties, and exceptional physicochemical properties. Such remarkable properties assert g-C3N4 as a potential candidate for the next-generation high-performance gas sensors employed in the detection of toxic and flammable gases. Although several articles and reviews are available on g-C3N4 for their synthesis, functionalities, and applications for the detection of humidity. Few of them has focused their attention on gas sensing using g-C3N4. Thus, in this review, we have methodically summed up the recent advances in g-C3N4 and its composites-based gas sensor for the detection of toxic and flammable gases. Moreover, we have also incorporated the synthesis strategies and the comprehensive physics of g-C3N4 based gas sensors. Additionally, different approaches are presented for the enhancement of gas sensing/detecting properties of g-C3N4 based gas sensors. Finally, the challenges and future scope of g-C3N4 based gas sensors for real-time monitoring of gases have been discussed.

MoS2-based multiple surface plasmonic coupling for enhanced surface-enhanced Raman scattering and photoelectrocatalytic performance utilizing the size effect

MoS₂-based heterostructures have received increasing attention for not only surface-enhanced Raman scattering (SERS) but also for enhanced photoelectrocatalytic (PEC) performance. This study presents a hydrothermal method for preparing vertical MoS₂ nanosheets composed of in situ grown AuNPs with small size and chemically reduced AgNPs with large size to achieve the synergistic enhancement of SERS and PEC properties owing to the size effect of the plasmonic structure. Compared with pristine MoS₂ nanosheets and unitary AuNPs or AgNPs composited with MoS₂ nanosheets, the ternary heterostructure exhibited the strongest electromagnetic field and surface plasmon coupling, which was confirmed by finite-difference time-domain (FDTD) simulation and absorption spectra. In addition, the experimental results confirmed the outstanding SERS enhancement with an EF of 1.1×10⁹, and the most efficient hydrogen evolution reaction (HER) activity with a sensitive photocurrent response, attributing to the multiple surface plasmonic coupling effects of the Au-Ag bimetal and efficient charge-transfer process between MoS₂ and the bimetal. That is, it provides a robust method for developing multi-size bimetal-semiconductor complex nanocomposites for high-performance SERS sensors and PEC applications.

Low crystalline 1T-MoS2@S-doped carbon hollow spheres as an anode material for Lithium-ion battery

A low crystalline 1T-MoS₂@S-doped carbon (MoS₂@SC) composite was successfully synthesized via a facile hydrothermal process. The composite is comprised by few-layer 1T-MoS₂ nanosheets covered by an amorphous carbon layer with an expanded interlayer d-spacing of 1.01 nm. This structure is conducive to the fast transport of lithium-ions and volume accommodation during the charge-discharge process when the composite is applied as an anode material for LIBs. Additionally, the high conductivity and layered structure of 1T-MoS₂ also facilitate fast of ion/electron transport, contributing to the improvement of the electrochemical properties. Therefore, this material demonstrated a high rate performance and excellent cycling stability, with the capacities of 847 and 622 mA h g^-1 achieved at the current densities of 0.2 A g^-1 and 2 A g^-1, respectively. Even at a larger current density of 2 A g^-1, MoS₂@SC delivered a high reversible capacity of 659 mA h g^-1 with an average capacity loss of 0.006% per cycle after 500 cycles.

Hierarchical fabrication of hollow Co2P nanocages coated with ZnIn2S4 thin layer: Highly efficient noble-metal-free photocatalyst for hydrogen evolution

The directional synthesis of transition metal phosphides was considered to be an effective strategy to solve the overdependence of noble metals on photocatalytic hydrogen evolution (PHE) reactions. Inspiringly, this work reported a facile method for constructing hollow Co₂P nanocages (Co₂P NCGs) that derived from ZIF-67 by calcining and phosphiding procedure in nitrogen atmosphere to act as non-noble metal cocatalysts. Followed with further coating thin-layered ZnIn₂S₄ (ZIS) on the surface of Co₂P NCGs through a hydrothermal reaction, the hierarchical robust Co₂P/ZnIn₂S₄ nanocages (Co₂P/ZIS NCGs) were then delicately fabricated as efficient photocatalysts for PHE reactions. The uniquely hollow structure of Co₂P NCGs largely diffused the photogenerated chargers that induced from ZIS and the closely interfacial contact significantly promoted the separation and transfer of electrons from ZIS to Co₂P according to density functional theory (DFT) calculation, synergistically resulting in an efficient hydrogen generation performance. PHE results showed that an efficient H₂ evolution rate of 7.93 mmol/g/h over 10% Co₂P/ZIS NCGs was achieved, about 10 times higher than that of pristine ZnIn₂S₄. More importantly, the hierarchically hollow Co₂P/ZIS NCGs exhibited ascendant PHE activity in comparison with that of 1% noble metal (Pt, Au, Ag) loaded ZnIn₂S₄ with superior sustainability, all indicating the efficient and stable photocatalysts of Co₂P/ZIS NCGs for PHE reactions.

Silver decorated 2D nanosheets of GO and MoS2serve as nanocatalyst for water treatment and antimicrobial applications as ascertained with molecular docking evaluation

In this work, synthesis of graphene oxide (GO) and reduced graphene oxide (rGO) was realized through a modified Hummers route. Different concentrations (5 and 10 wt%) of Ag were doped in MoS₂and rGO using a hydrothermal technique. Synthesized Ag-MoS₂and Ag-rGO were evaluated through XRD that confirmed the hexagonal structure of MoS₂along with the transformation of GO to Ag-rGO as indicated by a shift in XRD peaks while Mo-O bonding and S=O functional groups were confirmed with FTIR. Morphological information of GO and formation of MoS₂nanopetals as well as interlayer spacing were verified through FESEM and HRTEM respectively. Raman analysis was employed to probe any evidence regarding defect densities of GO. Optical properties of GO, MoS₂, Ag-rGO, and Ag-MoS₂were visualized through UV-vis and PL spectroscopy. Prepared products were employed as nanocatalysts to purify industrial wastewater. Experimental results revealed that Ag-rGO and Ag-MoS₂showed 99% and 80% response in photocatalytic activity. Besides, the nanocatalyst (Ag-MoS₂and Ag-rGO) exhibited 6.05 mm inhibition zones againstS. aureusgram positive (G+) and 3.05 mm forE. coligram negative (G-) in antibacterial activity. To rationalize biocidal mechanism of Ag-doped MoS₂NPs and Ag-rGO,in silicomolecular docking study was employed for two enzymes i.e.β-lactamase and D-alanine-D-alanine ligase B (ddlB) from cell wall biosynthetic pathway and enoyl-[acylcarrier-protein] reductase (FabI) from fatty acid biosynthetic pathway belonging toS. aureus. The present study provides evidence for the development of cost-effective, environment friendly and viable candidate for photocatalytic and antimicrobial applications.

The room temperature synthesis of a CuO-Bi-BiOBr ternary Z-scheme photocatalyst for enhanced sunlight driven alcohol oxidation

The room temperature synthesis of an all-solid-state Z-scheme CuO-doped BiOBr (CuO-Bi-BiOBr) photocatalyst has been described. These CuO-Bi-BiOBr ternary heterojunctions exhibit efficient photocatalytic activities for selective alcohol oxidation. The structures, morphologies, and compositions of the nanostructures were well characterized using field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and atomic absorption spectroscopy (AAS). The X-ray diffraction (XRD) pattern of the as-synthesized nanostructures confirms the formation of phase-segregated CuO and BiOBr nanocrystals, whereas X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) analyses clearly indicate the formation of metallic bismuth nanoparticles (NPs). Next, the developed CuO-Bi-BiOBr ternary heterojunctions were applied as an efficient photocatalyst for the oxidation of alcohols into their corresponding aldehydes/ketones with high selectivity (>99%) and high conversion ratios (>99%). Herein, Bi metal NPs act as an electron mediator and bridge the connectivity between the two semiconductors, BiOBr and CuO, and, thus, a Z-scheme heterojunction is established. As expected, CuO-Bi-BiOBr has shown significantly superior activities compared to those of pure BiOBr. A possible mechanism for the photocatalytic oxidation process has been proposed. Radical scavenging experiments suggest that the active species, h⁺, ˙OH, e^-, and ˙O₂^-, are dominant in the alcohol oxidation process. The as-synthesized CuO-Bi-BiOBr was reused several times without any significant deterioration in the original activities and it thus possesses relatively high stability for practical applications.

Photodeposition of Silver on Zinc/Calcium Ferrite Nanoparticles: A Contribution to Efficient Effluent Remediation and Catalyst Reutilization

The efficient photodegradation of textile dyes is still a challenge, especially considering resistant azo dyes. In this work, zinc/calcium mixed ferrite nanoparticles prepared by the sol–gel method were coupled with silver by a photodeposition method to enhance the photocatalytic potency. The obtained zinc/calcium ferrites are mainly cubic-shaped nanoparticles sized 15 ± 2 nm determined from TEM and XRD and an optical bandgap of 1.6 eV. Magnetic measurements indicate a superparamagnetic behavior with saturation magnetizations of 44.22 emu/g and 27.97 emu/g, respectively, for Zn/Ca ferrite and Zn/Ca ferrite with photodeposited silver. The zinc/calcium ferrite nanoparticles with photodeposited silver showed efficient photodegradation of the textile azo dyes C.I. Reactive Blue 250 and C.I. Reactive Yellow 145. Subsequent cycles of the use of the photocatalyst indicate the possibility of magnetic recovery and reutilization without a significant loss of efficiency.

A critical review on the applications and potential risks of emerging MoS2 nanomaterials

Molybdenum disulfide (MoS₂) nanomaterials have been widely used in various fields such as energy store and transformation, environment protection, and biomedicine due to their unique physicochemical properties. Unfortunately, such large-scale production and use of MoS₂ nanomaterials would inevitably release into the environmental system and then potentially increase the risks of wildlife/ecosystem and human beings as well. In this review, we first introduce the physicochemichemical properties, synthetic methods and environmental behaviors of MoS₂ nanomaterials and their typical functionalized materials, then summarize their environmental and biomedical applications, next assess their potential health risks, covering in vivo and in vitro studies, along with the underlying toxicological mechanisms, and last point out some special phenomena about the balance between applications and potential risks. This review aims to provide guidance for harm predication induced by MoS₂ nanomaterials and to suggest prevention measures based on the recent research progress of MoS₂' applications and exerting toxicological data.

Efficient photocatalytic degradation of acrylonitrile by Sulfur-Bismuth co-doped F-TiO2/SiO2 nanopowder

In this study, a simple sol-gel method was applied for preparing effectual photocatalyst of S-Bi co-doped F-TiO₂/SiO₂ (S-Bi-F-TiO₂/SiO₂) nanopowder. Optimal preparation conditions were obtained by optimizing the calcination temperature and the ratio of S and Bi. The synthesized powder was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), brunauer-emmett-teller (BET), UV-Visible diffuse-reflectance spectroscopy (UV-Vis DRS), photoluminescence spectroscopy (PL) and ammonia adsorption and temperature-programmed desorption (NH₃-TPD). The photocatalytic activity was evaluated by the degradation of acrylonitrile under simulated visible light irradiation. S-Bi-F-TiO₂/SiO₂ nanopowder possess excellent photocatalytic properties under visible light for the degradation of acrylonitrile, when the calcination temperature was 450 °C for 2 h and the ratio of S and Bi was 0.02: 0.007. The degradation efficiency of acrylonitrile reached to 81.9% within 6 min of visible light irradiation. Compared with F-TiO₂/SiO₂ sample, NH₃-TPD and PL results revealed the higher photocatalytic activity for S-Bi-F-TiO₂/SiO₂, which is mainly due to the increase strength and number of surface acid site with S doping. The co-doping with S & Bi improved the separation of electron-hole pairs and enhanced the photocatalytic oxidizing species. The UV-Vis DRS showed stronger absorption in S-Bi co-doped F-TiO₂/SiO₂ catalyst as compared to F-TiO₂/SiO₂ catalyst. XPS results demonstrated the presence of various surface species viz. oxygen vacancies, Ti³⁺, Ti⁴⁺, O^2- and OH group.

Transition Metal Dichalcogenides for the Application of Pollution Reduction: A Review

The material characteristics and properties of transition metal dichalcogenide (TMDCs) have gained research interest in various fields, such as electronics, catalytic, and energy storage. In particular, many researchers have been focusing on the applications of TMDCs in dealing with environmental pollution. TMDCs provide a unique opportunity to develop higher-value applications related to environmental matters. This work highlights the applications of TMDCs contributing to pollution reduction in (i) gas sensing technology, (ii) gas adsorption and removal, (iii) wastewater treatment, (iv) fuel cleaning, and (v) carbon dioxide valorization and conversion. Overall, the applications of TMDCs have successfully demonstrated the advantages of contributing to environmental conversation due to their special properties. The challenges and bottlenecks of implementing TMDCs in the actual industry are also highlighted. More efforts need to be devoted to overcoming the hurdles to maximize the potential of TMDCs implementation in the industry.

Synthesis and Characterization of Efficient ZnO/g-C3N4 Nanocomposites Photocatalyst for Photocatalytic Degradation of Methylene Blue

We examine the photocatalytic activity (PCA) of ZnO/graphitic carbon nitride g-C3N4 (g-CN) composite material for methylene blue (MB) degradation under visible-light irradiation (VLI). The polymeric g-CN materials were fabricated by the pyrolysis of urea and thiourea. More importantly, ZnO/g-CN nanostructured composites were fabricated by adding the different mounts (60, 65, 70, and 75 wt.%) of g-CN into ZnO via the simple hydrothermal process. Among fabricated composites, the 75% ZnO/g-CN nanocomposites displayed a superior PCA for MB degradation, which were ~three-fold an enhancement over the pure ZnO nanoparticles. The fabricated materials have been evaluated by X-ray diffraction (XRD), UV-Vis, Fourier transform infrared (FT-IR) spectroscopy, and electron microscopy. More importantly, the photodegradation of MB could get 98% in ZnO/g-CN could be credited to efficient separation of photo-induced charge carriers between ZnO and g-CN. Also, the recycling efficiency of the as-prepared composites was studied for multiple cycles, which shows that the photocatalysts are stable and suitable to carry out photocatalytic degradation in the logistic mode. Additionally, the probable photocatalytic mechanism has also discussed. The synthetic procedure of ZnO/g-CN based materials can be used in numerous fields such as environmental and in energy storage applications.

Current Trends in MXene-Based Nanomaterials for Energy Storage and Conversion System: A Mini Review

MXene is deemed to be one of the best attentive materials in an extensive range of applications due to its stupendous optical, electronic, thermal, and mechanical properties. Several MXene-based nanomaterials with extraordinary characteristics have been proposed, prepared, and practiced as a catalyst due to its two-dimensional (2D) structure, large specific surface area, facile decoration, and high adsorption capacity. This review summarizes the synthesis and characterization studies, and the appropriate applications in the catalysis field, exclusively in the energy storage systems. Ultimately, we also discussed the encounters and prospects for the future growth of MXene-based nanomaterials as an efficient candidate in developing efficient energy storage systems. This review delivers crucial knowledge within the scientific community intending to design efficient energy storage systems.

Nitrofurazone degradation in the self-biased bio-photoelectrochemical system: g-C3N4/CdS photocathode characterization, degradation performance, mechanism and pathways

In this study, a self-biased bio-photoelectrochemical system (SB-BPES) was constructed using a bioanode and the g-C₃N₄/CdS heterojunction photocathode for nitrofurazone (NFZ) degradation under solar irradiation. The physio-chemical properties and optical performance of photocatalysts were characterized, and photo-electrochemical properties of various photocathodes were analyzed. Results showed that g-C₃N₄/CdS exhibited the broadest visible light absorption range (to 594 nm) and the most efficient e^--h⁺ separation; and its corresponding photocathode showed the highest photocurrent (9.8 μA), and the lowest charge transfer resistance (5.43 ☓ 10³ Ω). In the solar-illuminated SB-BPES with g-C₃N₄/CdS photocathode, about 80% of NFZ removal rate was achieved within 10 h. More importantly, TOC removal of 62.6% was achieved in 24 h, which was 1.8 times of that from the open circuit SB-BPES, and 4.3 folds of that from microbial degradation; also, about 1.5 times of those from SB-BPES with g-C₃N₄ and CdS photocathodes. Besides, reproducible current generations (∼1.0 mA) were produced. These verified that it was a self-sustained system for spontaneously pollutants degradation and electricity generation. Moreover, possible degradation mechanism and pathways were proposed according to the identified intermediates. This study provides inspiration for synchronic improving refractory organics degradation and net energy recovery.

Visible light driven CuBi2O4/Bi2MoO6 p-n heterojunction with enhanced photocatalytic inactivation of E. coli and mechanism insight

Here, a novel CuBi₂O₄/Bi₂MoO₆ (CBO/BMO) p-n heterojunction was fabricated and exhibited markedly improved photocatalytic inactivation capacity of E. coli cells under visible light excitation (λ > 420 nm) compared with pure CuBi₂O₄ and Bi₂MoO₆. The CBO/BMO-0.5 hybrid displayed the highest photoinactivation ability which could completely inactivate the E. coli cellswithin 4 h. The mechanism of photocatalytic disinfection towards E. coli of CBO/BMO heterojunctions was attributed to the disruption of cell-membrane, leakage and damage of cellular content including total protein and DNA as verified with SEM, fluorescence-base dead/live stain, sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) and agarose gel electrophoresis (AGE). Additionally, the scavenge experiments showed that the reactive species h⁺, e^- and •O_2^-play the predominant role in the photocatalytic system of CBO/BMO hybrids. The improved photocatalytic activity of CBO/BMO composites was mainly attributed to the promotion of spatial separation and migration rate of photoproduced electron-hole pairs, enhancement of visible light absorption and more generation of reactive species (•O₂^-) on the interface of catalyst and water which was demonstrated by nitroblue tetrazolium (NBT) and EPR. Our work indicated that construction of CuBi₂O₄/Bi₂MoO₆ p-n heterostructure photocatalyst is a promising environmental friendly alternative method to deal with the biohazards of pathogenic microorganisms.

Synthesis and characterization of vanadium-doped Mo(O,S)2 oxysulfide for efficient photocatalytic degradation of organic dyes

We developed simple and low cost synthesis methods at low temperature to synthesize V-doped Mo(O,S)₂ for the photocatalytic degradation of dyes.

A facile template-free synthesis of Bi2Sn2O7 with flower-like hierarchical architecture for enhanced visible-light photocatalytic activity

A novel flower-like structure of Bi₂Sn₂O₇ was synthesized by a facile hydrothermal method which showed enhanced photodegradation of tetracycline.

Size-Dependent in Vitro Biocompatibility and Uptake Process of Polymeric Carbon Nitride

Polymeric carbon nitride (PCN), which demonstrates unique properties, has been widely explored, mostly in photocatalysis; however, the evaluation of its biocompatibility is still needed. Herein, the cytocompatibility of PCN with different lateral size distributions (A-PCN with 160 nm, B-PCN with 20 nm, and C-PCN with 10 nm dominating lateral sizes) was investigated. The viability of three cell lines (L929, MCF-7, and HepG2) has been determined using cell counting kit-8 (CCK-8), neutral red uptake (NRU), and lactate dehydrogenase (LDH) leakage assays. It was found that the highest cytotoxicity of PCN was observed for flakes with a lateral size of ∼20 nm (B-PCN) in three cell lines after 48 h of exposition. The uptake process of B-PCN sheets labeled with fluorescein isothiocyanate (FITC) by cells was also the most effective. Confocal laser scanning microscopy and atomic force microscopy revealed the nanomaterial distribution throughout the cytoplasm and perinuclear region. The results demonstrated the correlation among size, internalization process, and cytocompatibility of the tested polymeric carbon nitride structures.