Carbon Nitride Hybrid Research Articles

Thin NiFeCr-LDHs nanosheets promoted by g-C3N4: a highly active electrocatalyst for oxygen evolution reaction

NiFeCr layered double hydroxides (NiFeCr-LDHs) supported on graphitic carbon nitride (g-C3N4) hybrids (NiFeCr-LDHs/g-C3N4) are synthesized and used as an electrocatalyst for oxygen evolution reaction (OER) in alkaline media. Effect of g-C3N4 on the structure and OER performance of NiFeCr-LDHs are investigated in detail. g-C3N4 can promote the formation of thin NiFeCr-LDHs nanosheets, thereby enhancing both the number of active sites and OER activity. X-ray photoelectron spectra measurements confirm the electronic interaction between g-C3N4 and NiFeCr-LDHs nanosheets. The OER performance of NiFeCr-LDHs/g-C3N4 hybrids highly relates to the weight ratio of g-C3N4 to NiFeCr-LDHs. When the weight ratio of g-C3N4 to NiFeCr-LDHs is 5%, the corresponding electrocatalyst shows the best OER activity. The component optimized NiFeCr-LDHs/g-C3N4 hybrids display the overpotential of ∼223 mV at 10 mA cm−2 and Tafel slope of 89 mV dec−1 for OER in 1 M KOH solution, which is better than that of pristine NiFeCr-LDHs, bare g-C3N4, and commercial RuO2.

Bio-templated 3D porous graphitic carbon nitride hybrid aerogel with enhanced charge carrier separation for efficient removal of hazardous organic pollutants

Graphitic carbon nitride (g-C3N4) hybrid aerogels (GHAs) with different proportions of g-C3N4 were prepared using g-C3N4, carboxymethyl cellulose, and β-cyclodextrin. GHAs have demonstrated high porosity, large specific surface area, rich three-dimensional network structure. GHAs demonstrated an excellent synergistic effect on the photocatalytic and adsorptive properties. Especially, GHA1 (the ratio of g-C3N4 and aerogel component was 1:1) exhibited a good synergy in photodegradation and adsorption, with a Rhodamine B (Rh B) removal up to 97.99% in 90 min. In five cycling experiments, the GHA1 showed a good long-term stability. The aerogels can be easily isolated and maintains its excellent photocatalytic properties. Compared to pure g-C3N4, GHA1 has a stronger photocurrent, which is due to the transmission of light to the surface of the catalyst, promoted photo-generated electron-hole pairs, and inhibited recombination of electros and holes. Finally, mechanistic studies reveal that the superoxide radicals (O2−) are the main active groups in the photocatalytic degradation process. This work provides a useful perspective in design and fabrication of hybrid aerogel composites with an enhanced photocatalytic activity.

Multi-layered porous hierarchical TiO2/g-C3N4 hybrid coating for enhanced visible light photocatalysis

Traditional photocatalysts are difficile to conform the provision of visible light catalysis, conducive recycling and eminent efficiency, which limits their practical applications for decomposing organic pollutants in wastewater. Herein, a multi-layered porous hierarchical titanium dioxide/graphitic carbon nitride (TiO2/g-C3N4) hybrid coating is in-situ generated on titanium (Ti) substrate by sequentially employing plasma electrolytic oxidation (PEO), alkali immersing and hydrothermal reaction. The as-prepared coating exhibits surpassing photocatalytic performance to decay Rhodamine B (RhB) than g-C3N4 and TiO2 photocatalysts under 5 W LED visible light with 240 h cyclic stability. Moreover, the electrons transport and Z-scheme mechanism for TiO2/g-C3N4 hetero-junction is pursued to account for the ultralow recombination of photo-induced electron-hole and the enhanced catalytic properties. Not only that, it inhibits the secondary pollution which has further intensified its significance for degradation of organic pollution in sewage treatment systems.

Metal‐organic framework MIL‐53 (Fe)@C/graphite carbon nitride hybrids with enhanced thermal stability, flame retardancy, and smoke suppression for unsaturated polyester resin

Metal‐organic framework MIL‐53 (Fe)@C/graphite carbon nitride hybrid (MFeCN), a novel flame retardant, was synthesized by hydrothermal reaction and subsequently added into unsaturated polyester resin (UPR). The structure, morphology, and thermal stability of MFeCN were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDS), and thermogravimetric analysis (TG). The thermal stability and flammability of the UPR composites were characterized by TG and cone calorimeter tests (CCT). The results of CCT demonstrated that the peak heat release rate (pHRR), total heat release (THR), peak smoke production rate (pSPR), and total smoke production (TSP) of UPR/MFeCN‐4 were reduced by 39.8%, 10.2%, 33.3%, and 14.5%, respectively, comparing with UPR. The results of TG and CCT indicated that MFeCN could improve the thermal stability, flame retardancy, and smoke suppression properties of the UPR composites. The residues after CCT were then characterized by laser Raman spectroscopy (LRS), XPS, and SEM. Finally, based on the above experimental results and analysis, the flame retardancy mechanism of MFeCN was proposed.

Hemin-porous g-C3N4 hybrid nanosheets as an efficient peroxidase mimic for colorimetric and visual determination of glucose.

A method is described for colorimetric determination of glucose by using hemin-porous graphitic carbon nitride (g-C3N4) hybrid nanosheets as a peroxidase mimic. The porous g-C3N4 nanosheets were prepared by a combination of one-pot self-polymerization, pyrolysis and liquid-phase exfoliation. The hemin-porous g-C3N4 hybrid nanosheets were prepared via in-situ deposition. It is shown that the hybrid composite has improved dispersibility, stability, and peroxidase-mimicking activity in the 3,3',5,5'-tetramethylbenzidine (TMB)/H2O2 system. This is deemed to be the result of the synergistic effect of hemin and porous g-C3N4 nanosheets. Based on these advantages of the nanosheets, a simple, low-cost, sensitive and selective colorimetric method was established for the determination of glucose at pH values around 7. Best performed at a wavelength of 652nm, the assay has a linear response in the 10.0μM to 500μM glucose concentration range (R2= 0.9942) and a 1.94μM limit of detection. This method was successfully applied to the determination of glucose in (spiked) human serum samples. In our perception, the hybrid is a robust peroxidase mimic for use in POx-based assays as needed in medical diagnosis and environmental analysis. Graphical abstract Schematic presentation of the process of hemin-porous g-C3N4 hybrid nanosheets catalyzing the oxidation of peroxidase chromogenic substrate tetramethylbenzidine (TMB) in the presence of H2O2. The material was applied in colorimetric and visual determination of H2O2 and glucose.

Three-Dimensional Functionalized Carbon Nanotubes/Graphitic Carbon Nitride Hybrid Composite as the Sulfur Host for High-Performance Lithium–Sulfur Batteries

Improving the sulfur loading, conductivity, and polarity of the sulfur host is the main effective strategy used to solve the inherent problem of lithium–sulfur batteries for practical applications....

Modification of pyridinic N and O-rich defects in a bifunctional electrocatalyst with enhanced electrocatalytic performance

The modification of active sites in electrocatalysts is important for energy conversion and storage systems. Here, CoOx/N-doped graphene/polymeric carbon nitride (CoOx/NG/PCN) hybrid was prepared by thermal annealing method. The introduction of NG greatly prevented the aggregation of CoOx nanoparticles. Further doping PCN into CoOx/NG, CoOx/NG/PCN showed wrinkle and cross-linked structure. And the introduction of PCN can effectively increase the contents of pyridinic N and numbers of O defects to result in the improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance. Detailed experiments suggested that the onset and half-wave potentials (Eonset and E1/2) of CoOx/NG positively shifted of 110 and 100 mV, respectively compared to pure CoOx nanoparticles. When further doping PCN into CoOx/NG, Eonset and E1/2 were further positively shifted of 40 and 110 mV, respectively. More importantly, such ORR activity exhibited comparative activity and even more superior stability and excellent methanol tolerance than commercial Pt/C. Additionally, the resulted CoOx/NG/PCN also showed superior OER activity. Compared with CoOx/NG and CoOx, the overpotential of CoOx/NG/PCN for 10 mA/cm2 current densities was decreased for 160 mV and 180 mV, respectively. Especially, the investigation herein may assist in a new insight to bond configurations modification of catalysts and can be extended to other catalytic systems.

Praseodymium Vanadate-Decorated Sulfur-Doped Carbon Nitride Hybrid Nanocomposite: The Role of a Synergistic Electrocatalyst for the Detection of Metronidazole

The construction of efficient and superior nanostructured materials for the precise determination of contaminants that are hazardous to the environment has gained significant attention by the scientific community. In this regard, we fabricated a nanocomposite consisting of praseodymium vanadate (PrVO4; PrV) anchored to sulfur-doped carbon nitride (PrV/SCN) and applied it to the electrochemical detection of the antibiotic drug metronidazole (MTZ). The structural and crystalline features of the as-prepared PrV/SCN nanocomposite were characterized by various analytical and spectroscopic methods. More distinctly, the PrV/SCN nanocomposite-modified glassy carbon electrode (GCE) exhibits an outstanding linear range (0.001-2444 μM), high sensitivity (1.386 μA/μM cm2), low detection limit (0.8 nM), good reproducibility, and strong anti-interference ability. Notably, the PrV/SCN sensor can determine MTZ in spiked urine and water samples with high recoveries, suggesting its feasibility for real-time applications. Our findings establish PrV/SCN as a robust and promising platform for electrochemical detection. This promotes innovative design for the synthesis of novel functional nanocomposites.

Bimetallic PtAu Alloy Nanoparticles-Integrated g-C3N4 Hybrid as an Efficient Photocatalyst for Water-to-Hydrogen Conversion.

Herein, we report the synthesis of metal (Pt and Au) and metal alloy (PtAu) nanoparticles (NPs)-integrated graphitic carbon nitride (g-C3N4) hybrids using a facile solvothermal route for water-splitting application. The metal and metal alloy NPs with varying percentages of Pt and Au are found to be in the size range of 3-5 nm and uniformly distributed on the g-C3N4 sheets. The metal and metal alloy NPs act as cocatalyst for g-C3N4 to enhance the photocatalytic activity for hydrogen (H2) generation through higher light absorption and efficient charge separation. The alloy composition plays an important role to maximize the photoactivity, with an optimized PtAu/g-C3N4 sample delivered 1009 μmol g-1 h-1 of H2. The visible light assisted photocatalytic H2 evolution is further investigated with the optimized PtAu alloy NPs-integrated g-C3N4. This study presents a robust, stable, and easily synthesizable PtAu/g-C3N4 hybrid material as a promising photocatalyst for H2 generation through water splitting.

CuO-ZnO hetero-junctions decorated graphitic carbon nitride hybrid nanocomposite: Hydrothermal synthesis and ethanol gas sensing application

ZnO and CuO have attracted considerable attention for their potential application in gas sensors. However, they also have some disadvantages, such as high operating temperature and poor sensitivity. Graphitic carbon nitride (g-C3N4) has been widely used as metal-free catalyst and catalyst support in gas sensing field due to its unique chemical stability and excellent substrate characteristics. In this study, a one-step hydrothermal method was developed for the preparation of a CuO-ZnO/g-C3N4 ternary composite. The as-prepared samples were characterized by using the XRD, SEM, TEM, FTIR, UV–vis and XPS techniques. The analysis results indicated that the ternary composite was synthesized successfully. The morphological analyses demonstrated that the flake-like CuO and ZnO nanoparticles were wrapped and connected by g-C3N4 nanosheet. The as-prepared CuO-ZnO/g-C3N4 exhibited obviously enhanced sensing properties to ethanol, which were 1.34 times and 2.17 times higher than that of CuO-ZnO and CuO, respectively. The improving gas sensing properties were related to the valid p-n junctions of CuO-ZnO and excellent substrate effect of g-C3N4 nanosheet.

Self-assembly of tungstophosphoric acid/acidified carbon nitride hybrids with enhanced visible-light-driven photocatalytic activity for the degradation of imidacloprid and acetamiprid

In this paper, a novel efficient hybrid photocatalyst consisting of tungstophosphoric acid (HPW) and acidified carbon nitride (ACN) was successfully prepared. HPW and ACN interact through hydrogen bonding interactions to improve the photocatalytic activity of the HPW/ACN composite by means of enhanced photogenerated hole-electron separation efficiency. Graphitic carbon nitride was treated with a mixture of concentrated nitric acid and sulfuric acid to obtain porous ACN. The composite photocatalyst was then prepared by self-assembly of acidified carbon nitride and HPW under acidic conditions. The characterization results of HPW/ACN indicated the successful introduction of HPW and the effective interaction between HPW and ACN. Based on photocatalytic degradation experiments, it was concluded that HPW could act as the photogenerated electron trapping agent, providing adsorption sites as well as photocatalytic redox reaction sites. Moreover, the HPW/ACN showed excellent performance in the degradation of imidacloprid and acetamiprid under visible light irradiation (λ > 400 nm). The results of photocatalytic degradation revealed that the degradation rate constant of HPW/ACN (0.0058 min−1) was 16 times higher than that of ACN (3.55 × 10−4 min−1) in the photocatalytic degradation of imidacloprid and that the photocatalytic degradation rate constant of HPW/ACN (0.0017 min−1) was 30 times higher than that of ACN (5.64 × 10−5 min−1) in degrading acetamiprid.

A robust electrochemical immunosensor based on hydroxyl pillar[5]arene@AuNPs@g-C3N4 hybrid nanomaterial for ultrasensitive detection of prostate specific antigen

Prostate specific antigen (PSA) is the most significant biomarker for the screening of prostate cancer in human serum. However, most methods for the detection of PSA often require major laboratories, precisely analytical instruments and complicated operations. Currently, the design and development of satisfying electrochemical biosensors based on biomimetic materials (e.g. synthetic receptors) and nanotechnology is highly desired. Thus, we focused on the combination of molecular recognition and versatile nanomaterials in electrochemical devices for advancing their analytical performance and robustness. Herein, by using the present prepared multifunctional hydroxyl pillar[5]arene@gold nanoparticles@graphitic carbon nitride (HP5@AuNPs@g–C3N4) hybrid nanomaterial as robust biomimetic element, a high-performance electrochemical immunosensor for detection of PSA was constructed. The as-prepared immunosensor, with typically competitive advantages of low cost, simple preparation and fast detection, exhibited remarkable robustness, ultra-sensitivity, excellent selectivity and reproducibility. The limit of detection (LOD) and linear range were 0.12 pg mL–1 (S/N = 3) and 0.0005–10.00 ng mL–1, respectively. The satisfying results provide a promising approach for clinical detection of PSA in human serum.

Photocatalytic properties of copper-two dimensional graphitic carbon nitride hybrid film synthesized by pyrolysis method

Immobilized film based photocatalyst has drawn significant attention in environmental photocatalytic applications. In this current study, copper- graphitic carbon nitride (Cu-g-C3N4) photocatalyst was fabricated as a film by simple pyrolysis method and it’s structural, morphological and optical properties have been investigated by X-ray diffraction, scanning electron microscopy and photoluminescence spectroscopy. In pyrolysis reaction, we found that copper oxide (Cu2O) formation is highly inhibited in the presence of urea. The photocatalytic dye degradation efficiency of methylene blue is much higher in Cu-g-C3N4 photocatalyst compared with hierarchical Cu2O, glass- g-C3N4 and physical coated Cu-g-C3N4 film. Pseudo-first order rate constant of the hybrid film is nearly 1.4 fold greater than that of the bare hierarchical Cu2O. The enhanced of the photocatalytic reaction may be attributed to the reduction of electron-hole recombination in g-C3N4. The prepared film can be used for consecutive multiple photocatalytic cycles without efficiency loss and structural changes. Our findings may provide a new pathway to the waste-water treatment and its related applications.

Controllable construction of polymer/inorganic interface for poly(vinyl alcohol)/graphitic carbon nitride hybrid pervaporation membranes

Highly water-selective hybrid pervaporation membranes with excellent water/ethanol separation performance and superior water channels were fabricated by incorporating graphitic carbon nitride (g-C3N4), activated g-C3N4 (O-g-C3N4) and polydopamine modified g-C3N4 (PDA@O-g-C3N4) nanosheets into poly(vinyl alcohol) (PVA) matrix. The nonselective polymer/inorganic interface channels between PVA and g-C3N4, O-g-C3N4 and PDA@O-g-C3N4 in hybrid membranes were controllable constructed through hydrogen bonds, rigid and flexible chemical bonds, respectively. The membrane performances were tested in the pervaporation (PV) process for the dehydration of 90 wt% ethanol/water mixtures at 75 °C. The results revealed that with the increase of binding force among polymer/inorganic interface, from hydrogen bonds (CPVA-g-C3N4), to rigid (CPVA-O-g-C3N4) and flexible chemical bonds (CPVA-PDA@O-g-C3N4), the total flux decreased from 4634 to 2328 g/(m2h) and the separation factor increased from 32.4 to 57.9. It is implied that the nonselective polymer/inorganic interface channels were controlled successfully. Meanwhile, compared with the pure cross-linked PVA (CPVA) membrane (total flux 2325 g/(m2h) and separation factor 18.7), incorporation of g-C3N4, O-g-C3N4 and PDA@O-g-C3N4 could all lead to an increase of surface hydrophilicity of the CPVA membranes along with an increase in membrane tortuosity and membrane water-selective channels that was favorable to the selective permeation of water molecules. Namely, these new hybrid membranes can break the “trade-off effect” effectively. Moreover, due to the ordered alignment of g-C3N4, O-g-C3N4 and PDA@O-g-C3N4 nanosheets and the strong interfacial interactions among these nanosheets, succinic acid (Sa) and the PVA matrix, the hybrid composite membranes showed both high swelling resistance and mechanical stability.

Buckling behavior of boron nitride nanotubes under combined axial compression and torsion via molecular dynamics simulations

Buckling behavior of boron nitride nanotubes under combined axial compression and torsion is presented by using molecular dynamics simulation. In order to study the effect of helicity and nanotube size, three groups of nanotubes are considered. The first group is a pair of boron nitride nanotubes with a similar geometry but different helicities, the second group includes three armchair naotubes having equal length but different radii, and three armchair (8, 8)-nanotubes with different lengths form the third group. The simulation is conducted by applying Nose-Hoover thermostat in a temperature range from 50 K to 1200 K. Based on the interatomic interactions given by Tersoff-type potentials, the molecular dynamics method is used to study variations of atomic interaction in initial linear deformation and postbuckling stages with various load-proportional parameters, and to determine the interactive buckling loads relationship. By comparing typical buckling modes under different loads, it is found that the boron nitride nanotube experiences complex micro-deformation processes, resulting in different variations of atomic interaction and strain energies. When the axial compressive load is relatively large, the change of atomic interaction for boron nitride nanotubes under combined loads is similar to that found under the pure axial compression. The onset of buckling leads to the abrupt releasing of strain energy. As the torsional load is relatively large, the nanotube shows torsion-like buckling behavior, no obvious reduction of strain energy is observed after the critical point. The present simulation results show that both the armchair and zigzag nanotubes exhibit nonlinear interactive buckling load relationships. Rise in temperature results in the decrease of interactive buckling load, and the effect of temperature varies with the value of load-proportional parameter. That is, the axial compressive load is relatively large, and the effect of temperature is more significant. It is found that the buckling behavior in the case of combined loading is strongly size dependent. The interactive critical axial and shear stress decrease as nanotube radius or length increases. The studies also reveal that under both simple loading and combined load condition, carbon nanotubes possess higher buckling loads than those of boron nitride nanotubes with a similar geometry, which provides valuable guidance for forming carbon and boron nitride hybrid nanotubes as well as coaxial nanotubes with superior mechanical properties.

In situ fabrication of CDs/g-C3N4 hybrids with enhanced interface connection via calcination of the precursors for photocatalytic H2 evolution

Novel carbon dots (CDs)/graphitic carbon nitride (g-C3N4) hybrids were fabricated via an in situ thermal polymerization of the precursors, urea and glucose. This heterojunction catalyst exhibited enhanced photocatalytic H2 evolution activity under visible-light (λ > 420). A sample of CDs/g-C3N4 hybrids, CN/G0.5, which was prepared from 0.5 mg of glucose in 6.0 g of urea (8.3 × 10−3 wt% glucose), exhibited the best photocatalytic performance for hydrogen production from water under visible light irradiation, which is about 4.55 times of that of the bulk g-C3N4 (BCN). The improvement of photocatalytic activity was mainly attributed to the construction of built-in electric field at the interface of CDs and g-C3N4, which could improve the separation of photogenerated electron-hole pair. Moreover, the tight connection of CDs with g-C3N4 would serve as a well electron transport channel, which could promote the photocatalytic H2 evolution ability.

Z-scheme electronic transfer of quantum-sized α-Fe2O3 modified g-C3N4 hybrids for enhanced photocatalytic hydrogen production

A quantum-sized hematite iron oxide (α-Fe2O3)/graphitic carbon nitride (g-C3N4) hybrids have been designed and constructed through a facile in situ calcination treatment. The α-Fe2O3/g-C3N4 hybrids were analyzed via various characterization techniques including XRD, TEM, UV–Vis DRS, XPS, and their photocatalytic efficiencies were evaluated by visible light-driven hydrogen evolution. The results reveal that the cooperation of α-Fe2O3 and g-C3N4 during fabrication process leads to synergy effects of not only the morphology but also the microstructure. These hybrids exhibit much higher hydrogen evolution efficiency than pure g-C3N4 under visible-light illumination due to their improved light harvesting capability, enhancement of surface areas, predominant (110) facet exposure of α-Fe2O3 as well as a prominent quantum size effect, and highly efficient electron transfer and separation. A proposed Z-scheme mechanism was further verified experimentally.

In situ decoration of plasmonic Au nanoparticles on graphene quantum dots-graphitic carbon nitride hybrid and evaluation of its visible light photocatalytic performance

This work spotlights the development of a plasmonic photocatalyst showing surface plasmon induced enhanced visible light photocatalytic (PC) performance. Plasmonic Au nanoparticles (NPs) are decorated over the hybrid nanosystem of graphitic carbon nitride (GCN) and graphene quantum dots (GQD) by citrate reduction method. Surface plasmon resonance (SPR) induced enhancement of Raman G and 2D band intensity is encountered on excitation of the Plasmonic hybrid at 514.5 nm, which is near to the 532 nm absorption band of Au NPs. Time-resolved photoluminescence and XPS studies show charge transfer interaction between GQD-GCN and Au NPs. Plasmonic hybrid exhibits an enhanced PC activity over the other catalysts in the photodegradation of methylene blue (MB) under visible light illumination. Plasmonic photocatalyst displays more than 6 fold enhancement in the photodecomposition rate of MB over GQD and nearly 2 fold improvement over GCN and GQD-GCN. GQD-GCN absorbs mostly in the near visible region and can be photoexcited by visible light of wavelength () < 460 nm. Plasmon activation in Au NPs decorated GQD-GCN could exploit the entire UV–visible light for photocatalysis. Furthermore, plasmonic Au act as antennas for accumulation and enhancement of localized electromagnetic field at the interface with GQD-GCN, and thereby promotes photogeneration of large numbers of carriers on GQD-GCN. The carriers are separated by charge transfer migration from hybrid to Au NPs. Finally, the carriers on the plasmonic Au nanostructures initiate MB degradation under visible light. Our results have shown that plasmon decoration is a suitable strategy to design a carbon based hybrid photocatalyst for solar energy conversion.

A Mixed‐Metal Oxides/Graphitic Carbon Nitride: High Visible Light Photocatalytic Activity for Efficient Mineralization of Rhodamine B

Novel photocatalysts in the form of zinc oxide‐zinc bismuth oxide (mixed‐metal oxide [MMO]) and graphitic carbon nitride (CN) hybrid composites are developed via a co‐precipitation method followed by calcination at 520 °C. The as‐prepared MMO‐CN hybrid composites are evaluated on the basis of their photocatalytic activities for Rhodamine B (RhB) in aqueous solutions under visible light irradiation. The strong electronic coupling between two components within the MMO‐CN heterostructure, which suppresses the photogenerated recombination of electrons and holes to a remarkable extent, is revealed. The prepared composites exhibit an excellent photocatalytic activity, leading to more than 95% of RhB degradation at an initial concentration of 50 mg L−1 using 0.5 g catalyst per liter in 90 min, along with 25 min of the RhB half‐life time. The excellent photocatalytic mineralization of MMO‐4.0CN by visible light irradiation can be attributed to the synergic effects for high and charge transfer between MMO and CN as well as efficient separation of photogenerated electrons and holes. The species most responsible for photodegradation is holes (h +) with moderate and minor contributions by the superoxide anion and hydroxyl radicals, respectively. These results attest to a green, low cost, and high efficiency photocatalyst for environmental remediation.

Peroxymonosulfate enhanced visible light photocatalytic degradation bisphenol A by single-atom dispersed Ag mesoporous g-C3N4 hybrid

Single-atom dispersed Ag modified mesoporous graphitic carbon nitride (Ag/mpg-C3N4) hybrid was synthesized by co-condensation method and employed as a visible light photocatalyst. In the presence of peroxymonosulfate (PMS), Ag/mpg-C3N4 showed excellent performance for the degradation of bisphenol A (BPA). 100% BPA and 80% TOC could be removed with 0.1g/L catalyst and 1mM PMS under visible light (λ>400nm) within 60min. The reason for the enhanced performance is possibly due to the synergistic effect of single-atom Ag and mpg-C3N4. On the one hand, more visible light could be captured with the introduction of Ag; on the other hand, the existence of PMS promotes the separation efficiency of photogenerated electron-hole pairs. Electron spin resonance (ESR) and free radicals quenching experiment suggest that the major reactive oxygen species (ROS) are sulfate radical (SO4−), superoxide radicals (O2−) and photogenerated holes, while the role of hydroxyl radicals (OH) is insignificant in this process. The findings of this work highlighted the great potential of g-C3N4 as photocatalysts and elucidated a new opportunity for PMS remediation of contaminated water.