Synthesis of Au-NiOx/ultrathin graphitic C3N4 nanocomposite for electrochemical non-platinum oxidation of methanol

The Au-NiO_x/g-C₃N₄ (graphitic C₃N₄) nanocomposite is synthesized and utilized as catalyst for the electrochemical oxidation of methanol in the alkaline electrolyte. Au and Ni nanoparticles are uniformly dispersed on ultrathin g-C₃N₄ nanosheets by in-situ synthesis with nickel nitrate and chloroauric acid as Ni and Au resource respectively. The structure, morphology and component of the prepared nanocomposites are characterized by different techniques like transmission electron microscopy, X-ray diffraction, elemental mapping image and X-ray photoelectron spectroscopy. The results prove that the nanoparticles are well-distributed and embedded in g-C₃N₄ nanosheets. The electrochemical performance of different nanocomposite for methanol oxidation reaction (MOR) is tested under alkaline conditions via electrochemical technologies. Compared to the pure g-C₃N₄ and Au/g-C₃N₄, the NiO_x/g-C₃N₄ exhibits electrochemical catalytic effect toward methanol electro-oxidation with the existence of Ni. This electrochemical catalytic performance is enhanced significantly for the Au-NiO_x/g-C₃N₄, whose oxidation peak current density is 2.32 times higher than NiO_x/g-C₃N₄. The slope value drew from the Tafel plots shows that the Au-NiO_x/g-C₃N₄ owns the lowest Tafel slope (67.00 mV/dec). After the 7200 s stability test, the Au-NiO_x/g-C₃N₄ catalyst can still maintain a high current density. Long-term stability and good anti-poisoning ability promise Au-NiO_x/g-C₃N₄ a competitive non-Pt catalyst for the methanol oxidation.     

The significant promotion of g-C3N4 on Pt/CNS catalyst for the electrocatalytic oxidation of methanol

This article reported a series of g–C₃N₄–CNS (g-C₃N₄ and carbon nanosheets) composite carriers formed by the hydrothermal method, and then the ethylene glycol reduction method was used to anchor Pt nanoparticles on the g–C₃N₄–CNS carrier to form the Pt/g–C₃N₄–CNS catalysts. The electrochemical test for the electrocatalytic oxidation of methanol (MOR) shown that the Pt/20%g–C₃N₄–CNS catalyst has the best catalytic performance and stability. These Pt/g–C₃N₄–CNS catalysts were analyzed by TEM, XRD, XPS, and BET characterization. It is discovered that the amount of g-C₃N₄ greatly influenced the structure and chemical properties of Pt/CNS precursor. As the content of g-C₃N₄ increases, the content of pyridine nitrogen and pyrrole nitrogen also increases, and N species can enhance the interaction between Pt nanoparticles and CNS, promote Pt dispersion, and increase the specific surface area of the catalyst. Similarly, an excessive addition of g-C₃N₄ will cause a sharp decline in the conductivity of the catalyst, and then led to the decline of MOR activity.     

Efficient hydrogen production over MOFs (ZIF-67) and g-C3N4 boosted with MoS2 nanoparticles

MOFs (ZIF-67) and g-C₃N₄ catalyst-modified MoS₂ nanoparticles are prepared by means of doping g-C₃N₄ in the process of ZIF-67 formation and then introducing MoS₂ nanoparticles on the surface of collaborative structure between MOFs and g-C₃N₄. The MOFs (ZIF-67) and g-C₃N₄ catalyst-modified MoS₂ photocatalyst exhibits efficient hydrogen production with about 321 μmol under visible light irradiation in 4 h, which is almost about 30 times higher than that of over the pure g-C₃N₄ photocatalyst. A series of characterization studies such as SEM, XRD, TEM, EDX, XPS, UV–vis DRS, FTIR, transient fluorescence and electro-chemistry show that the novel structure of g-C₃N₄ and MOF is formed, the more active sites appears and the efficiency of photo-generated charge separation is improved. MoS₂, as a narrow band semiconductor, is grafted on the surface of g-C₃N₄/MOF, which could effectively harvest visible light and swift charge separation. The results are well mutual corroboration with each other. In addition, a eosin Y-sensitized reaction mechanism is introduced.     

Performance of g-C3N4 nanoparticles by EDTA modification and protonation for hydrogen release from sodium borohydride methanolysis

Here, for the first time, a metal-free catalyst was synthesized by ethylenediamine tetra-acetic acid (EDTA) modification of the carbon nitride (g-C₃N₄) sample and protonation of the obtained sample. The catalyst was used for the production of H₂ from the methanolysis of sodium borohydride (NaBH₄). The EDTA modification and protonation of the g-C₃N₄ sample was confirmed by XRD, FTIR, SEM-EDX, and TEM analyses. During the hydrogen generation, NaBH₄ concentration effect, catalyst amount effect, temperature effect and catalyst reusability were investigated. The HGR value obtained with 2.5% NaBH₄ using 10 mg catalyst was 7571 mL min^?1g^?1. The activation energy (Ea) for the g–C₃N₄–EDTA-H catalyst was found to be 32.2 kJ mol^?1 The reusability of the g–C₃N₄–EDTA-H catalyst shows a catalytic performance of 72% even after its fifth use.     

Greatly enhanced photocatalytic hydrogen production on CdS/(Pt/g-C3N4) via dual functions of Pt on semiconductors interface

CdS and g-C₃N₄ are famous semiconductors in photocatalytic hydrogen evolution, however, their low efficiencies limit their further application. Here, a highly efficient ternary catalyst CdS/(Pt/g-C₃N₄) was reported and its photocatalytic hydrogen production activity reached up to 1465.9 μmol/h/g, which is 5.3 times of Pt/CdS and 4.0 times of Pt/g-C₃N₄, respectively. TEM and HRTEM images demonstrate the Pt nanoparticles exists on the interface of between CdS and g-C₃N₄ acting as a cocatalyst for hydrogen evolution. SPV spectra and electrochemical tests demonstrate that Pt as bridge between CdS and g-C₃N₄ also accelerates the electrons transforming which benefits for the inhibition of the recombination of photoexcited electrons and holes. This study demonstrated the dual roles of interface Pt and provides a new method to design a highly efficient photocatalyst.     

Influence of Rh nanoparticle size and composition on the photocatalytic water splitting performance of Rh/graphitic carbon nitride

The effect of Rh co-catalyst nanoparticle size for photocatalytic water splitting using graphitic carbon nitride (g-C₃N₄) as light absorber was investigated. Rh nanoparticles with sizes in the 4–9 nm range were synthesized and deposited on g-C₃N₄. The light-absorption properties of the g-C₃N₄ and the particle size of Rh supported on g-C₃N₄ were also not influenced by the catalyst synthesis procedures. Rh/C₃N₄ is active in the photocatalytic splitting of water using visible light. The activity for H₂ generation does not depend on Rh particle size. The results obtained point to two important design criteria for a successful photocatalyst: firstly, the surface of the semiconductor should support a sufficient number of Rh nanoparticles to remove the photogenerated electrons before their recombination with holes; secondly, the nanoparticles should be metallic in nature to catalyze the proton-electron transfer reaction to generate adsorbed H atoms. Surface oxidation of the Rh nanoparticles substantially lowers their photocatalytic activity.     

One-pot calcination preparation of graphene/g–C3N4–Co photocatalysts with enhanced visible light photocatalytic activity

Photocatalytic technology for hydrogen evolution from water splitting and pollutant degradation is one of the most sustainable methods. Here, the graphene/g–C₃N₄–Co composite materials have been prepared by one-pot calcination method. The results show that g-C₃N₄ grow on the surface of graphene and form a sandwich structure, meanwhile, the introduction of Co increases the active sites, which promotes the photocatalytic performance. The influences of graphene and Co content on photocatalytic activity were also studied by UV–visible spectrophotometry (DRS), photoluminescence spectroscopy (PL), photocurrent, degradation MB, and hydrogen production. The apparent reaction rate constant k of graphene/g–C₃N₄–Co (3%) is 0.946 h⁻¹, which is 4.90 and 2.18 times faster than g-C₃N₄ and graphene/g-C₃N₄, respectively. And the hydrogen production rate of graphene/g–C₃N₄–Co (3%) (892.3 μmol h⁻¹ g⁻¹) is 3.53 and 1.61 times higher than g-C₃N₄ and graphene/g-C₃N₄, respectively.     

Pt@Ni2P/C3N4 for charge acceleration to promote hydrogen evolution from ammonia-borane

Incorporating g-C₃N₄ with transition metal phosphides is emerging as a low-cost and robust co-catalyst for hydrogen evolution. The ammonia borane hydrolysis is an efficient method to release H₂ at ambient conditions in the presence of a catalyst. An efficient and cheap catalyst is needed for practical application to achieve this benchmark. For this purpose, a catalyst Ni₂P/C₃N₄ is synthesized by hydrothermal method and low-temperature phosphidation. The optimization reveals that the Ni₂P/C₃N₄ with 6.5% Ni contents shows the best performance for H₂ release. Furthermore, 2% Pt nanoparticles loading over Ni₂P/C₃N₄ boosts the charge transfer and improves activity 5.7-fold compared to Ni₂P/C₃N₄, and the Pt-loaded catalyst is depicted as Pt@Ni₂P/C₃N₄. The reaction kinetics reveals that the hydrogen evolution rate accelerates by increasing the amount of Pt@Ni₂P/C₃N₄ and AB concentration, and the loading of Pt nanoparticles loaded over Ni₂P/C₃N₄ reduces the activation energy significantly. Moreover, the ionic interaction between Pt and Ni₂P/C₃N₄ generates Ptᵟ⁺ and (Ni₂P/C₃N₄)ᵟ⁻ active sites which facilitates B–H cleavage and O–H bonds of ammonia borane and water, respectively. Incorporating transition metals phosphide and noble metals supported over g-C₃N₄ paves the pathway toward the efficient H₂ evolution from ammonia borane, bringing cost-effective modifications to synthesize constructive catalysts.     

Nano-structured palladium impregnate graphitic carbon nitride composite for efficient hydrogen gas sensing

Nanoparticles of palladium (Pd) were incorporated into graphitic carbon nitride (g-C₃N₄) matrix with a view to improving hydrogen sensing efficiency of g-C₃N₄, by a fairly new chemical process that uses ammonium tetrachloropalladate as a Pd metal nanoparticle source along with an appropriate reducing agent. Researchers have explored g-C₃N₄ for various applications such as a catalyst for water splitting, photoluminescence, storage because of its relatively low cost, easy synthesis, and ready availability. For the synthesis of g-C₃N₄, urea was used as a precursor at 550 °C and at atmospheric pressure under a muffle furnace without add-on support. The final solution of the Pd/g-C₃N₄ nanocomposite was then centrifuged and dried for use as a hydrogen-sensing material. g-C₃N₄ and Pd/g-C₃N₄ were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), UV-VIS-NIR spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS). Pd-dispersed graphitic carbon nitride film was deposited on an inter digited carbon electrode by using a screen printing technique. From the qualitative analysis by I–V measurement, a significant change in the resistance was observed during the presence and absence of the hydrogen gas. The results show Pd/g-C₃N₄ nanocomposite as an efficient hydrogen sensing material.     

Surface plasmon assisted photocatalytic hydrogen generation with Ag decorated g-C3N4 coupled SnO2 nanophotocatalyst under visible-light driven photocatalysis

Photocatalytic hydrogen evolution from water is a feasible technique to solve energy crises and reduce dependance on carbon fuels. As for this, silver nanoparticles were grown on the surface of SnO₂ coupled g-C₃N₄ nanocomposite for the generation of hydrogen gas from water under visible light photocatalysis. The prepared samples were properly characterized to investigate their light absorption characteristics followed by charge generation and separation for water splitting. The optimized nanocomposite produced 270 μmol h⁻¹ g⁻¹ hydrogen which was much superior to pure g-C₃N₄ and SnO₂. These upgraded photocatalytic activities were attached to the extended visible-light absorption due to the presence of Ag nanoparticles characterized by surface plasmon resonance (SPR) and suitable conduction bands position of g-C₃N₄ and SnO₂ for the separation of excited charges. The photoluminescence study, amount of produced hydroxyl free radicals and electrochemical investigation confirmed the long-rooted charge separation capability of the nanocomposites. We believe that this work will have more positive impacts on the synthesis of low cost SPR assisted photocatalysts for energy production and environmental purification.     

Experiments combined with theoretical research on the effect of hydrogen evolution by the nanosheet of NiS–CdS–CN catalyst

A ternary composite photocatalyst of nickel sulfide supported on the heterojunction of ultrathin cadmium sulfide-carbon based on g-C₃N₄ nanosheets was prepared by aqueous-phase in low-temperature innovatively, and its chemical compositions were confirmed by XRD, FT-IR and XPS. The morphology of two-dimensional nanosheet heterojunction was verified by SEM, TEM, HRTEM and BET, and the addition of nickel is beneficial to improve the specific surface area of the catalyst. The larger surface area was more beneficial to accelerate the carrier migration and reactant diffusion. Meanwhile, the electron structures were analyzed by UV–vis, work function, bader charge and ELF charge calculated by GGA-PBE, which proved that the electrons at heterojunction interface of CdS–C₃N₄ were transferred from g-C₃N₄ to CdS, and the strong interaction existed in two layers between CdS and g-C₃N₄ by reformed the bonds of Cd–N, and the doping Ni can regulate the interface electron transport mechanism of CdS–C₃N₄ heterojunction. The hydrogen evolution performance showed that the ternary composite photocatalyst was better than both of the single system of cadmium sulfide or carbon nitride and the binary system containing NiS–CdS or CdS–C₃N₄. Through the characterization and theoretical calculation of the results, we found that the synergistic effect of NiS–CdS–C₃N₄ system could solve the problems of high recombination rate of photo-electrons and holes, and insufficient active sites existing in single materials of g-C₃N₄ or CdS during the photocatalytic reaction.     

Magnetic Fe3C@C nanoparticles as a novel cocatalyst for boosting visible-light-driven photocatalytic performance of g-C3N4

In photocatalytic field, it is a significant challenge to synthesize cocatalyst with high performance, noble-metal free and facile methods to recycle. Herein, carbon layer coated Fe₃C (Fe₃C@C) nanoparticles were prepared by one-step method and for the first time utilized as highly efficient cocatalysts for improving visible-light-driven hydrogen evolution activity of g-C₃N₄. The photocatalytic hydrogen evolution rate of optimal Fe₃C@C/g-C₃N₄ was about 27.2 times of bare g-C₃N₄ samples. Furthermore, the Fe₃C@C/g-C₃N₄ composite catalyst showed excellent stability and reusability. The apparent quantum yield (AQY) of the optimized FeC@C/g- C₃N₄ reaches 0.501% and 0.124% at 400 nm and 420 nm, respectively. The AQY of the FeC@C/g- C₃N₄ is 26.2 times higher than that of g-C₃N₄ at 400 nm Fe₃C@C has an extraordinary cocatalytic effect for g-C₃N₄ photocatalytic hydrogen evolution mainly due to three aspects: Firstly, the Fe₃C acts as a trap to lure electrons because of its lower Fermi energy level and higher conductivity, which can increase the hydrogen production activity by trapping the photogenerated electrons produced by g-C₃N₄; Secondly, the coated carbon layer can provide chemical protection for Fe₃C nanoparticles and promote the transfer of photogenic electrons, thus further improving the efficiency and stability of photocatalytic hydrogen production; Thirdly, the strong magnetic property of Fe₃C@C nanoparticles gives Fe₃C@C/g-C₃N₄ photocatalysts the advantages of low cost and high recovery efficiency. It is believed that this work provides a new strategy and possibility for the application of photocatalytic hydrogen production.     

Graphitic carbon nitride heterojunction photocatalysts for solar hydrogen production

Photocatalytic hydrogen production is considered as an ideal approach to solve global energy crisis and environmental pollution. Graphitic carbon nitride (g-C₃N₄) has received extensive consideration due to its facile synthesis, stable physicochemical properties, and easy functionalization. However, the pristine g-C₃N₄ usually shows unsatisfactory photocatalytic activity due to the limited separation efficiency of photogenerated charge carriers. Generally, introducing semiconductors or co-catalysts to construct g–C₃N₄–based heterojunction photocatalysts is recognized as an effective method to solve this bottleneck. In this review, the advantages and characteristics of various types of g–C₃N₄–based heterojunction are analyzed. Subsequently, the recent progress of highly efficient g–C₃N₄–based heterojunction photocatalysts in the field of photocatalytic water splitting is emphatically introduced. Finally, a vision of future perspectives and challenges of g–C₃N₄–based heterojunction photocatalysts in hydrogen production are presented. Predictably, this timely review will provide valuable reference for the design of efficient heterojunctions towards photocatalytic water splitting and other photoredox reactions.     

A facile one-step strategy to construct 0D/2D SnO2/g-C3N4 heterojunction photocatalyst for high-efficiency hydrogen production performance from water splitting

Fabricating 0D/2D heterojunctions is considered to be an efficient mean to improve the photocatalytic activity of g-C₃N₄, whereas their applications are usually restricted by complex preparation process. Here, the 0D/2D SnO₂/g-C₃N₄ heterojunction photocatalyst is prepared by a simple one-step polymerization strategy, in which SnO₂ nanodots in-situ grow on the surface of g-C₃N₄ nanosheets. It shows the outstanding photocatalytic H₂ production activity relative to g-C₃N₄ under the visible light, which is due to the formation of 0D/2D heterojunction significantly contributing to the separation of photogenerated charge carriers. In particular, the H₂ production rate over the optimal SnO₂/g–C₃N₄–1 sample is 1389.2 μmol h⁻¹ g⁻¹, which is 6.06 times higher than that of g-C₃N₄ (230.8 μmol h⁻¹ g⁻¹). Meanwhile, the AQE value of H₂ production over the SnO₂/g–C₃N₄–1 sample reaches up to a maximum of 4.5% at 420 nm. This work develops a simple approach to design and fabricate g–C₃N₄–based 0D/2D heterojunctions for the high-efficiency H₂ production from water splitting.     

Synthesis of CuTi-LDH supported on g-C3N4 for electrochemical and photoelectrochemical oxygen evolution reactions

A nanocomposite CuTi layered double hydroxide (LDH) supported on g-C₃N₄ (15 wt% of g-C₃N₄) is facilely synthesized by hydrothermal method. There are electrostatic interactions between positive layers of CuTi-LDH and negatively charged inner g-C₃N₄ sheets. The nanocomposite and its precursors are characterized through various analytical techniques, which affirmed the presence of both g-C₃N₄ and CuTi-LDH characteristic features. The pore-enriched hybrid geometry of CuTi-LDH@g-C₃N₄ with high specific surface area (146 m²/g), and suitable band gap of 2.46 eV enables the nanocomposite to act as both an electrocatalyst and photoelectrocatalyst for oxygen evolution reaction (OER). Both the electrochemical and photoelectrochemical studies are done using 1 M KOH (pH = 13.6) with applied potential of ?0.2 V to 1.5 V vs. Ag/AgCl. The onset potential of CuTi-LDH@g-C₃N₄ for OER appears at η = 0.36 V in dark and η = 0.32 V under visible light illumination of 30 min. Also, Mott-Schottky analysis shows n-type semiconductor behaviour for CuTi-LDH@g-C₃N₄ and its precursors. The photoelectrochemical water oxidation proceeds by charge transfer across a Type II heterojunction formed between the CuTi-LDH and g-C₃N₄ materials.     

Fabrication of alveolate g-C3N4 with nitrogen vacancies via cobalt introduction for efficient photocatalytic hydrogen evolution

Photocatalytic hydrogen evolution is a promising method for converting solar energy into chemical energy. Herein, on the basis of graphitic carbon nitride (g-C₃N₄) material with alveolate structure prepared via the hard template method, transition-metal cobalt oxide nanoparticles were reasonably introduced, and a highly efficient cobalt oxide composite alveolate g-C₃N₄ (ACN) photocatalyst was successfully prepared. A series of test methods were used to characterize the structural properties of the prepared samples systematically, and the photocatalytic activity of the catalysts in photocatalytic hydrogen evolution was explored. The composite materials have excellent photocatalytic performance mainly because the synergistic effect of the alveolate structure of ACN provides multiple scattering effects; nitrogen vacancies serves as the centers of photogenerated carrier separation; and cobalt oxides accelerates electron transfer. This study provides a new idea for the design of g–C₃N₄–based photocatalysts with wide light responses and simple structures.     

Sustainable hydrogen production by CdO/exfoliated g-C3N4 via photoreforming of formaldehyde containing wastewater

Graphitic carbon nitride (g-C₃N₄) has been well-known as an appealing semiconducting material for photocatalytic hydrogen production despite its restricted active sites and poor electronic properties. In this work, exfoliated g-C₃N₄ nanosheets were synthesised by chemical treatment of the bulk graphitic carbon nitride (gCN) and the nanosheets were further doped with CdO. The photocatalysts produced were extensively characterized by diverse analysis including XRD, BET, XPS, TEM, FESEM, UV-Vis spectroscopy and PL analysis. The BET surface area of CdO/exfoliated g-C₃N₄, 40.1 m² g⁻¹ was doubled in comparison to the exfoliated g-C₃N₄. Numerous electrochemical analyses such as Mott-Schottky, linear weep voltammetry and chronoamperometry were also performed in a standard photoelectrochemical system with three-electrode cell. The hydrothermally synthesised CdO/exfoliated g-C₃N₄ resulted higher amount of hydrogen evolution (145 μmol/g) for the photoreforming of aqueous formaldehyde than the CdO (20 μmol/g), bulk gCN (58 μmol/g) and exfoliated g-C₃N₄ (87 μmol/g). The excellent hydrogen production rate using CdO/exfoliated g-C₃N₄ nanocomposite could be ascribed by higher number of active sites as well as shorter path of the charge carries to the reaction surface. The anticipated Z-Scheme mechanism has demonstrated a synergistic impact between the CdO and exfoliated g-C₃N₄ where the organic compounds acting as hole scavenger as well as contribute protons, H⁺ for the effective hydrogen production. Thus, it is clearly confirmed that the newly formulated CdO/exfoliated g-C₃N₄ has an outstanding potentiality for environmental remediation and conversion sectors.     

Construction of Au/g-C3N4/ZnIn2S4 plasma photocatalyst heterojunction composite with 3D hierarchical microarchitecture for visible-light-driven hydrogen production

In this paper, a novel Au/g-C₃N₄/ZnIn₂S₄ plasma photocatalyst heterojunction composite with 3D hierarchical microarchitecture has been successfully constructed by integrating Au/g-C₃N₄ plasmonic photocatalyst composite with 3D ZnIn₂S₄ nanosheet through a simple hydrothermal process. The Au nanoparticles were firstly anchored on the surface of pristine g-C₃N₄ material to get Au/g-C₃N₄ plasmonic photocatalyst. Ascribing to the surface plasmon resonance of Au nanoparticles, the obtained Au/g-C₃N₄ plasmonic photocatalyst shows a significant improved photocatalytic activity toward hydrogen production from water with visible light response comparing with pristine g-C₃N₄. Further combining Au/g-C₃N₄ plasmonic photocatalyst with 3D ZnIn₂S₄ nanosheet to construct a heterojunction composite. Owing to the synergistic effect of the surface plasmon resonance of Au nanoparticles in Au/g-C₃N₄ and the heterojunction structure in the interface of Au/g-C₃N₄ and ZnIn₂S₄, the prepared Au/g-C₃N₄/ZnIn₂S₄ plasma photocatalyst heterojunction composite shows an excellent photocatalytic activity toward hydrogen production from water with visible light response, which is around 7.0 and 6.3 times higher than that of the pristine C₃N₄ and Znln₂S₄ nanosheet, respectively. The present work might provide some insights for exploring other efficient heterojunction photocatalysts with excellent properties.     

Ag–AgBr/g-C3N4/ZIF-8 prepared with ionic liquid as template for highly efficient photocatalytic hydrogen evolution under visible light

In this study, a ternary photocatalyst named Ag–AgBr/g-C₃N₄/ZIF-8 (A/g/Z) was prepared by ionic liquid assisted in-situ growth method. The structure and composition of samples are studied by means of XRD, SEM, XPS, TEM, EIS, etc. The AgBr prepared by ionic liquid assisted method has good dispersion, and the protonated carbon nitride has better specific surface area and morphology structure. The structure of the composites is optimized by modifying g-C₃N₄ with MOFs and noble metals, and the existence of Ag⁺ can play a bridging role, so as to form multi-path electronic transmission route. The high efficiency of electron transfer greatly improved the efficiency of hydrogen evolution. It is worth noting that the surface plasmon resonance (SPR) effect produced by silver ions on the surface of g-C₃N₄ can improve the absorption of visible light. The A (1.1)/g/Z (6.5) exhibit high hydrogen evolution efficiency (2058 μmol g^?1 h^?1, which is 49 times than g-C₃N₄) at the absence of Pt co-catalyst. Furthermore, the transient photocurrent density of the composites is much higher than that of g-C₃N₄ and AgBr, the semicircle radius of EIS is also less than both. Through the five cycle experiment, the photocatalytic efficiency of the composite material remained above 91%.     

Enhancing the yield of H2O2 and bisphenol A degradation via a synergistic effect of photoelectric co-catalysis by using NPC/C3N4 electrode

This study reported a photoelectric co-catalyst system of jet-flow reactor for efficient mineralization of Bisphenol A (BPA), where H₂O₂ was photoelectro-generated in situ from O₂ reduction on gas diffusion electrodes fabricated by nitrogen-doped porous carbon and graphitic carbon nitride (NPC/g-C₃N₄). Current density, aeration rate, amount of MoS₂ and FeSO₄ catalyst in the jet-flow reactor photoelectrocatalysis system for BPA removal were investigated. The NPC/g-C₃N₄ cathodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and the electrochemical workstation. The results show that at pH 7, the NPC/g–C₃N₄–(60%) has the highest rate of electrical generation hydrogen peroxide. When the pH rised, at pH values of 7, the cumulative of hydrogen peroxide increased, when the solution get slight alkaline, it was gradually decreased. Compared with the traditional electro-Fenton technology, the photoelectric method of co-catalysis has strong ·OH production rate and high oxidation ability. A possible mechanism for BPA degradation was oxidized by hydroxyl radical (·OH), resulting in the formation of shorter chain bisphenol A (BPA), which followed the same reaction cycle as BPA until it was mineralized. The removal rate of BPA can reach 100% within 20 min, the TOC removal rate up to 90%. This work provides new opinion into the development of a photoelectric collaborative system for H₂O₂ generation and the fast BPA degradation.