g-C3N4 Sheets Research Articles

NiFe2O4/G-C3N4 modified pencil graphite electrode for mercury(II) detection

The design and development of composite electrodes towards the trace-level detection of Hg(II) ions has triggered paramount importance in the area of electrochemistry. In this context, pencil graphite electrode was modified with NiFe2O4/G-C3N4, wherein bimetallic oxides were heterogeneously grown over the g-C3N4 sheets through a wet chemical approach. The results derived from transmission electron microscopy and X-ray diffraction analysis indeed reflected that NiFe2O4 were uniformly distributed over the sheet surface and complemented with effective interactions between them. The composites were coated over a pencil graphite electrode (PGE) and were used for the electrochemical detection of Hg(II) ions under various conditions. The cyclic voltammetry (CV) and differential pulse anodic stripping voltammetry (DPASV) reveal better electrochemical performance of modified electrodes compared to bare PGE, G-C3N4/PGE, and NiFe2O4/PGE. The improved charge transfer kinetics at the electrode-electrolyte interface were the dominant factor to exhibit higher performance. The proposed sensor showed acceptable reproducibility and stability under the optimal reaction conditions. Additionally, the sensor showed a broad linear range from 10 to 800 nM with a limit of detection (LOD) of 2.49 nM. Further, the fabricated sensor has been successfully employed to determine Hg(II) contents in real water sample matrices.

Synthesis of 1D/2D VO2 (B) nanowire/g-C3N4 hybrid architectures as cathode materials for high-performance Li-ion batteries

Owing to energy density, powder density, and eco-friendliness, Li-ion batteries (LIBs) are increasingly used in transportable electronic devices and electric vehicles. Monoclinic VO2 (B) has been broadly used as a cathode owing to its abundance, affordability, high capacity, and multiple oxidation states, but it's low repeatability and slow kinetics have restricted its practical applications. To mitigate these shortcomings, novel 1D/2D VO2 (B) nanowire/g-C3N4 hybrid architecture cathode materials were synthesized via hydrothermal method, and its electrochemical activity (i.e., repeatability constancy and rate capability) for LIBs was investigated. X-ray diffraction experiments confirmed that VO2 (B) exhibited a monoclinic crystal phase. SEM images revealed that the g-C3N4 and VO2 (B) presented sheet-like morphologies and comprised nanowires of uniform thickness, respectively. Electrochemical experiments revealed that the hybrid architectures showed a capacity of 779 mAh/g, and VO2 (601.4 mAh/g) and g-C3N4 (340.6 mAh/g) at 0.1 C current density. The remarkable electrochemical activity of the materials was attributed to their distinctive structures, excellent electronic conductivity associated with g-C3N4 sheets, small transport distances for Li+ ions, and fast charge transmission owing to the presence of VO2 (B) nanowires attached to g-C3N4 sheets. Consequently, distinct VO2 (B) nanowire/g-C3N4 hybrid architectures delivered suitable electrode performance to facilitate the design of high-power LIBs and these hybrid composites can serve as suitable cathode materials for rechargeable LIBs.

Construction of Z-scheme FeTiO3/g-C3N4 heterojunction system: Characterization and statistical optimization of photocatalytic behavior under visible light irradiation

Construction of low-cost and green photocatalysts is an emerging subject in wastewater treatment processes. In the present study, FeTiO3/g-C3N4 (FTO/CN) photocatalytic system was constructed via ultrasonication followed by thermal mixing method. The synthesized FTO/CN hybrids with different CN ratios were characterized by SEM-EDX, TEM, XRD, XPS, XRF, UV–vis DRS, PL techniques. The photodegradation efficiencies of the hybrid materials were systematically examined towards decolorization of tartrazine dye under visible light irradiation. Using the FTO/CN hybrid catalyst, the photocatalytic efficiency of the pristine FeTiO3 greatly enhanced from 39.8% to 90.5%, which was attributed to appropriate band alignment and heterojunction transfer mechanism to hinder the recombination rate of photo-excited charge carriers. The effects of initial pollutant concentration (10–30 mg/L), catalyst dosage (0.1–0.5 g/L) and peroxymonosulfate (PMS) concentration (1–3 mM), as independent variables on the degradation efficiency were investigated by response surface methodology with Box-Behnken design model. Under optimized conditions (R2 = 0.99, R2adj = 0.98), the highest removal efficiency (100 %) was obtained with 0.5 g/L catalyst, 10 mg/L initial dye concentration and 3 mM PMS. The photodegradation efficiency of the hybrid system was investigated towards other pollutants (Sunset yellow, orange II, tetracycline and ciprofloxacin) and recyclability of the catalyst was also explored. The obtained results demonstrated that the hybridization of FeTiO3 particles with g-C3N4 sheets greatly enhanced the photocatalytic properties of FeTiO3 under different conditions.

2D g-C3N4 nanosheets functionalized with nickel-doped ZrO2 nanoparticles for synergistic photodegradation of toxic chemical pollutants

The photocatalytic removal of toxic chemical pollutants from wastewater has garnered significant attention in recent times owing to its notable removal efficiency, cost-effectiveness, and eco-friendly characteristics. Nonetheless, this catalytic process necessitates augmented charge separation and distinctive interface properties to facilitate catalytic reactions for water treatment applications. Therefore, in the current study, novel g-C3N4/Ni-doped ZrO2 heterostructured hybrid catalysts have been synthesized via a hydrothermal approach. Microscopic studies reveal that ZrO2 nanospheres were distributed on the layered-like 2D structure of g-C3N4 nanosheets. Electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (UV-DRS), and photoluminescence (PL) characterizations were employed to investigate the impact of bandgap, electron-hole recombination, charge transfer, and interface properties on the catalytic performance of g-C3N4/ZrO2 hybrids. XRD analysis confirmed that the Ni-ions do not disturb the host lattice crystal structure and heterostructure development between g-C3N4 and doped ZrO2 sample. Structurally, Ni-doped nanoparticles were found to be equally superficially dispersed on g-C3N4 sheets. Optical analysis results suggest that the hybrid catalyst possesses a narrow bandgap of 2.56 eV. The synthesized photocatalyst degraded rhodamine B (RhB) and tetracycline (TC) with ∼92% and ∼89% degradation efficiency, respectively. Heterostructured hybrid catalysts showed superior degradation rate constants than other catalysts. This might be attributed to the sufficient separation of electron-hole due to the development of a heterojunction. The radical scavenging experiments suggested that O2●- and ●OH radicals contributed substantially to the dye elimination activity of the composite. Therefore, the synthesized novel nanohybrid catalysts in this study present an efficient and straightforward synthesis method for the efficient removal of toxins from wastewater under visible light irradiation.

Bayberry-like Cu3BiS3 with 2D layered nanosheets of rGO and g-C3N4 for effective electrochemical HER activity

Hydrogen production via electrochemical water splitting is still considered as solution for global energy demand. The ternary composite material of copper bismuth sulfide/reduced graphene oxide/graphitic carbon nitride (Cu3BiS3/rGO/g-C3N4) electrocatalyst was produced via hydrothermal for HER activity. The X-ray diffraction study revealed that Cu3BiS3 with carbon composite have orthorhombic phase with an average crystallite size as 43.1 nm. The Raman spectra of Cu3BiS3 with carbon (rGO/g-C3N4) composite revealed the existence of structural defects with ID/IG ratio of 1.01. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies was explored bayberry-like Cu3BiS3 nanosphere formation with finely unified rGO and g-C3N4 sheets. In an alkaline medium, the electrocatalytic performance demonstrates the enhancement of the Cu3BiS3 catalyst due to the addition of rGO/g-C3N4 with the low 111 mV overpotential and small 113 mV/dec Tafel slope value. The electrochemical active surface area (ECSA) of Cu3BiS3 with carbon (rGO/g-C3N4) composite was 127.25 cm2, whereas the ECSA values of Cu3BiS3 and Cu3BiS3/rGO were 34.25 and 86.5 cm2, respectively. The results conclude that π-π interaction among rGO and g-C3N4 can effectively improve the conductivity, active sites, surface area and porous nature of the obtained product, which leads to enhance HER performance. Therefore, morphology tuned carbon composite material would be a promising candidate in forthcoming cost-effective and large-scale water splitting applications.

Design of a New ZnCo2O4 Nanoparticles/Nitrogen-Rich g-C3N4 Sheet with Improved Photocatalytic Activity Under Visible Light

Design of a New ZnCo2O4 Nanoparticles/Nitrogen-Rich g-C3N4 Sheet with Improved Photocatalytic Activity Under Visible Light

A metal-free catalyst based on g-C3N4 functionalized with cyamelurate-like groups: Catalytic properties and mechanism of a new heterogeneous Fenton-like catalyst

We prepared fragments of polymeric g-C3N4 sheets functionalized with cyamelurate-like functional groups, evaluated their Fenton-like catalytic properties and proposed a reaction mechanism for the formation of hydroxyl radicals on the surface of the materials in presence of H2O2. The controlled fragmentation/functionalization of g-C3N4 was characterized by a variety of techniques including SEM, TEM, FTIR and potentiometric titration. The performance of the catalysts proved to be dependent on both the cyamelurate-like functional groups and the conjugated structure of the polymeric g-C3N4 sheets, with the kinetics of the catalyzed reaction being faster at higher pH. In addition, in the absence of the contaminant, no significant consumption of hydrogen peroxide was observed. The reaction mechanism of oxidizing radicals formation was elucidated using cyclic voltammetry and EPR spectroscopy in parallel with theoretical calculations based on the estimate of the reaction Gibbs free energy of HO• and HOO• radicals formation, generated through the reaction of surface functional groups and hydrogen peroxide. In a broader context, the results showed may contribute to the development of strategies for studying and elucidating the reaction mechanisms involving metal-free catalysts, one of the main challenges in the area and, enabling the surface designing of metal-free catalysts for different oxidation reactions.

A greener approach to synthesize magnetically separable and photocatalytic recyclable g-C3N4-Fe3O4 nanomaterial for removing toxic organic dyes from water

A greener and eco-friendly approach was developed to prepare magnetic g-C3N4-Fe3O4 nanocomposite adsorbent. Here, first g-C3N4 was prepared from melamine by using simple thermal treatment method. Then magnetic Fe3O4 nanoparticles were introduced on 2D surface of g-C3N4 using guava leaf extract. The formation, functionality, morphologies, surface area, magnetic power and bonding of the prepared material were analysed by XRD, FTIR, FESEM, TEM, BET, VSM and XPS analytical techniques. The formation of Fe3O4 phase on g-C3N4 surface was confirmed by XRD analysis. TEM images confirmed the formation of fine NPs on 2D g-C3N4 sheet. The surface area was found to be 92.32 m2/g with BJH average pore size distribution of 4 nm.The saturation magnetization value of g-C3N4-Fe3O4 was 15.12 emu/g. This shows superior magnetic property of the prepared material and thus can easily be separated from the treated water using external magnet. The prepared material was used for the removal of commonly used toxic Congo red (CR) and Methylene blue (MB) dyes from water using batch adsorption method. The adsorption of CR and MB on the surface of adsorbent was pH dependent. The maximum adsorption capacity of CR was found to be 194 mg/g at pH=6 and MB was found to be 149 mg/g at pH=8. The CR and MB adsorption process follows Pseudo- second-order kinetic and Langmuir isotherm models. The adsorbed CR and MB were recovered from the surface of adsorbent using chemical free photocatalytic irradiation process under visible light. The regenerated adsorbent was also reused for the further adsorption study and showed significant adsorption efficiency. This novel material can be considered as a promising adsorbent for CR and MB dyes with high adsorption efficiency, high stability, eco-friendly synthesis and easy to separate from the treated water with good reusability power.

Wet-chemical engineering of Ag-BiVO4/Bi2S3 heterostructured nanocomposite on graphitic carbon nitride (g-C3N4) sheets for high performance supercapacitor application

Graphitic carbon nitride (g-C3N4), a structural analogue of graphite has opened a new arena in energy storage. The N-rich g-C3N4 sheets similar to N-doped carbon materials provide large number of defect sites for increased diffusion and adsorption of electrolyte ions. High N-content in g-C3N4 is most suitable to escalate metal‑carbon binding energy which stabilizes the pseudo-active transition metal oxides/chalcogenides over carbon support to realize high capacitive performance. In this study, we have impregnated binary Ag-BiVO4/Bi2S3 heterostructures on g-C3N4 sheets through wet-chemical approach, as novel electrode material for supercapacitor application. As prepared Ag-BiVO4/Bi2S3@g-C3N4 composite (ABVBS@g-C3N4) along with Ag-BiVO4/Bi2S3 (ABVBS), Ag-BiVO4 (ABV), and Bi2S3 (BS) were systematically characterized by different techniques i.e., XRD, FTIR, FESEM, EDS, and BET analysis. When applied for electrochemical tests, among all the analyzed electrodes ternary composite ABVBS@g-C3N4 exhibited highest electrochemical activity with a specific capacitance value of 872 F/g (@5 mV/s) and 815.4 F/g (@1 A/g), and 91.5 % capacitance retention up to 5000 GCD cycles. The initial coulombic efficiency of ABVBS@g-C3N4 was noteworthy (99.42 %) due to very low internal resistance. Moreover, it was analyzed that ternary composite ABVBS@g-C3N4 has lower equivalent series resistance (RES) as 6.73 Ω and charge transfer resistance value as 7.73 Ω, in comparison to other electrodes. This excellent electrochemical performance of ABVBS@g-C3N4 is attributed to combined contributions from ABVBS and g-C3N4 in terms of multiple redox states, increased wettability of electrode, and high structural and chemical stability. Considering the results, our study proposes feasible strategy to generate hybrid electrode materials with optimized properties to serve as energy storage material for next generation supercapacitors.

Ultra-small bimetallic CoNi nanoalloy decorated on 2D g-C3N4 enables high performance and long durability for asymmetric supercapacitor

Alloying metals change their characteristics significantly. Nanoalloy electrodes are excellent materials for pseudocapacitors, which bridge supercapacitors and batteries. We report an ultra-small bimetallic CoNi nanoalloy functionalized on 2D graphitic nitride (g-C3N4) sheets via hydrogenation. An asymmetric supercapacitor of CoNi@g-C3N4 nanoalloy fabricated with activated carbon nanofiber (ACF) shows a wide potential window of 1.5 V and an excellent life span of 8000 cycles at an ultra-high current density of 15 A g−1. Further, we operated the cell at 2 °C, RT, 50 °C and 65 °C, which shows an enhanced energy density of 26 Wh kg−1 at 50 °C than at a lower temperature (2 °C) of 15 Wh kg−1.

Significant enhancement of photocatalytic activity of g-C3N4/vermiculite composite by the introduction of nitrogen defects

Nitrogen-defect g-C3N4/vermiculite composites (gCVx, x = 0.1, 1, 3, 4) with high efficient photocatalytic performance were constructed by a wet chemical method cooperating with the calcination process, as well as using the pre-expanded vermiculite and the melamine pre-treated by hydrochloric acid solutions of 0.1, 1, 3, 4 mol/L, respectively. Micron-sized g-C3N4 sheets with nitrogen defects were synthesized and uniformly distributed in the gCVx composites. Photocatalytic performance was evaluated by degrading Rhodamine B (RhB) aqueous solution. The results indicated that photocatalytic activities of gCVx increased firstly and then dropped down gradually with the increase of HCl concentration. gCV3 achieved the maximum degradation rate of 97.90 % for RhB after photocatalysis for 20 min, whose degradation rate constant was 14.9 times than that of bulk g-C3N4. gCV3 also exhibited the highest photocatalytic activity toward degrading the tetracycline and phenol solutions. The excellent photocatalytic performance was ascribed to the enhanced amounts of active sites, increased specific surface area, improved visible light absorption ability, accelerated charge transfer and separation efficiency of photogenerated-carriers, which resulted from the synergistic effect between vermiculite and nitrogen defects in g-C3N4, as well as the mutual electrostatic repulsion between the negative-charged vermiculite and the photo-induced electron from the nitrogen-defect g-C3N4.

Synthesis and characterization of graphitic carbon nitride composite with NiFe2O4/CdO for photocatalytic treatment of diclofenac sodium and crystal violet

Herein, we report the photocatalytic degradation of anti-inflammatory drug i.e. diclofenac sodium, and organic dye i.e. crystal violet by CdO nanoparticles, NiFe2O4 nanoparticles, CdO/NiFe2O4, and ternary composite of CdO/NiFe2O4/g-C3N4. The easy/facile co-precipitation method was employed for the synthesis of nanoparticles, and their binary and ternary composite was fabricated by an ultra-sonication method. Characterization techniques used were XRD, FTIR, and SEM for the structural, functional group, and morphological analysis respectively. UV–Visible measurements were performed to determine the band gap energy of as-synthesized photocatalysts, and also to examine degradation efficiency of materials against crystal violet and diclofenac sodium under visible light source. Experimental analysis shows that the ternary nanocomposite of CdO/NiFe2O4/g-C3N4 has shown better photodegradation activity of 86% and 84% towards the diclofenac sodium and crystal violet respectively as compared to pure CdO and NiFe2O4 nanoparticles, and their binary composite. The improved degradation efficiency of ternary nanocomposite i.e. CdO/NiFe2O4/g-C3N4 is due to its high surface area/more active sites provided by g-C3N4 sheets for trapping of electrons in order to avoid electron/hole recombination and also to species for degradation. Hence, CdO/NiFe2O4/g-C3N4 nanocomposite could be a promising material in future to degrade other organic pollutants/dyes.

Synthesis and photocatalytic application of g-C<sub>3</sub>N<sub>4</sub>/rGO based metal oxide semiconductors

Metal oxide semiconductor materials onto g-C3N4 and rGO as photocatalysts have attracted considerably due to its potential application in different fields, special in environmental treatment. In this paper, we report the synthesís of ZnO/g-C3N4/rGO through hydrothermal method from ZnO/g-C3N4 and rGO. The effect of ratio of the ZnO và g-C3N4 on the structural and morphology of the synthesized nanoparticles were perfomed. The obtained results from characterization methods such as XRD, SEM, FT-IR, EDX,… showed that the materials have a high crystallinity, and ZnO particles were dispersed highly onto g-C3N4 sheets as well as layers of graphene oxide reduced. The photocatalytic activity of ZnO/g-C3N4/rGO was estimated through the degradation of Ciprofloxacin (CIP) in aqueous solution. CIP decomposition efficiency is up to 90% after 240 minutes exposuring to sun light irradiation.

Ternary CoFe2O4/g-C3N4/ZnO heterostructure as an efficient and magnetically separable visible-light photocatalyst: Characterization, dye purification, and mechanism

Recently, hybrid materials have received considerable attention due to the spatial dissociation of photogenerated electron-hole pairs, enabling them to harvest solar light from ultraviolet to visible regions. This study investigates the photocatalytic activity of magnetic CoFe2O4/g-C3N4/ZnO (CF-gCN/ZnO) nanocomposite as a visible-light photocatalyst. CoFe2O4 and ZnO were decorated on the surface of as-prepared g-C3N4 sheets using the precipitation technique. The structural, morphology, optical, and magnetic properties of the photocatalysts were investigated. Rietveld refinement confirmed the hexagonal wurtzite structure with the P63mc space group of ZnO. Diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) measurements showed that the optical properties and the electron-hole behavior of ZnO are affected by g-C3N4 nanosheets. The photocatalytic capability was assessed against methylene blue (MB) dye as a model pollutant under visible light irradiation. Compared to CoFe2O4/ZnO and CoFe2O4/gC3N4 composites, the heterojunction CF-gCN/ZnO photocatalyst achieved a photodegradation efficiency of 89% for degradation of MB after 100 min of irradiation. The formation of heterojunction structures at the interface of g-C3N4 and ZnO leads to improved photocatalytic activity due to the separation of the photo-generated electron-hole pairs. Additionally, the magnetic properties of the CoFe2O4 component provided the separation of the photocatalyst from the solution under an external magnetic field. The present study offers a facile method for designing CoFe2O4/g-C3N4/ZnO nanocomposite as a potential ternary photocatalyst with high efficiency and good separability for environmental remediation applications.

Highly selective and real-time detection of 5-hydroxymethylcytosine in genomic DNA using a carbon nitride-modified gold transducer-based electrochemical sensor

Cancer biomarkers are crucial indicators of cancer status and progression that aid in early detection and more effective treatment of the disease. The loss of 5-hydroxymethylcytosine (5hmC), an oxidation product of 5-methylcytosine (5mC), is a recurrent epigenetic biomarker across various types of cancers. Therefore, accurately quantifying 5hmC holds great potential for various clinical applications. However, distinguishing 5hmC from 5mC using conventional methods is challenging. In this study, we developed a rapid and highly selective electrochemical sensor for label-free detection of 5hmC-enriched DNAs using a graphitic carbon nitride (g-C3N4)-modified gold transducer. Two-dimensional g-C3N4 sheets were synthesized via direct pyrolysis of urea under ambient or nitrogen atmospheres and drop-cast onto the gold electrode. Subsequently, 5hmC-containing DNAs were immobilized onto g-C3N4 via hydrogen bonding between the –OH of 5hmC and the -NH2 of g-C3N4. The developed sensor demonstrated high sensitivity, selectivity, remarkable reproducibility, and stability, with a low oxidation potential (0.23 V) and an extremely low limit of detection (0.316 pM) for 5hmC. The sensor was also tested for its applicability to real samples using primary liver samples from mouse models, in which 5hmC levels were diminished due to either Tet gene knockout or hepatocellular carcinogenesis. The sensor effectively detected reduced genomic 5hmCs in TET-deficient livers and hepatocellular carcinomas compared to controls. Thus, this novel sensing strategy has the potential to develop clinically applicable sensors for early cancer diagnosis and prognosis evaluation by rapidly quantifying genomic 5hmC.

Direct Z-Scheme CoFe2O4-Loaded g-C3N4 Photocatalyst with High Degradation Efficiency of Methylene Blue under Visible-Light Irradiation

Magnetically recyclable direct Z-scheme CoFe2O4-loaded g-C3N4 photocatalyst material was fabricated using a facile hydrothermal technique and subsequently characterized by XRD, VSM, PL, FT-IR, EDX, DRS, SEM, and BET techniques. The characterization results confirmed that nanoparticles of CoFe2O4 are loaded on the surface of g-C3N4 sheets. The optical band gap of g-C3N4 has been decreased from 2.65 eV to 1.30 eV by means of the loading of CoFe2O4 nanoparticles onto the nanosheets of g-C3N4. This has enhanced the separation process of electron-hole. Under visible light irradiation, the photocatalytic activity of the developed direct Z-scheme CoFe2O4-loaded g-C3N4 photocatalyst was evaluated for the photodegradation of methylene blue (MB); during this process the MB decomposed by up to 98.86% in 140 min. Meanwhile, under the same irradiation and time conditions, the g-C3N4 and CoFe2O4 themselves degraded MB up to 74.92% and 51.53%, respectively. The direct Z-scheme CoFe2O4-loaded g-C3N4 material was recovered from the solution after the photocatalytic activity using an external magnet and studied to determine its stability. It was shown that the photoactivity did not change significantly after five consecutive cycles.

Synthesis and Characterization of Z-Scheme Heterojunction CoWO4/RGO/g-C3N4 as a Visible Light-Driven Photocatalyst for Novel Removal of Organic Pollutant

In this study, novel Z-scheme heterojunction photocatalyst CoWO4/RGO/g-C3N4 was successfully fabricated by a facial hydrothermal. Obtained morphology and topography studies indicated that deposition of reduced graphene oxide (RGO) and CoWO4 nanoparticles did not affect the structure of g-C3N4 sheets. However, optical results showed that visible light absorption of the material was significantly improved. The synthesized heterojunction photocatalyst exhibited improved photocatalytic performance in the novel degradation of rhodamine B, even upon visible irradiation. The improved photocatalytic performance was ascribed to interfacial contact between g-C3N4 and CoWO4 in a Z-scheme heterojunction in which RGO served as electron mediator accelerating its transfer between g-C3N4 and CoWO4 to minimize recombination of photogenerated electron-hole pairs. Therefore, rhodamine B degradation by CoWO4/RGO/g-C3N4 was 1.87 times higher than pristine g-C3N4. The synthesized heterojunction was relatively stable with no distinct reduction in photocatalytic activity after three recycling runs. The fabrication of heterojunction CoWO4/RGO/g-C3N4 is an efficient strategy to develop high-performance photocatalysts for various photocatalytic applications.

Novel g-C3N4/BiVO4 heterostructured nanohybrids for high efficiency photocatalytic degradation of toxic chemical pollutants

Novel heterostructured hybrid catalysts are essential for the efficient photocatalytic removal of organic pollutants from wastewater generated by the pharmaceutical and textile industries. In this study, novel g-C3N4/BiVO4 nanohybrid catalysts were prepared using a solvothermal technique, and examined their structural and optical properties using different characterizations. The X-ray diffraction analysis confirmed the monoclinic crystal phase of BiVO4. Field emission scanning electron microscopy (FESEM) images revealed that g-C3N4 sheets anchored on the surface of BiVO4 nanospheres. X-ray photoelectron spectroscopy (XPS) analysis confirmed the oxidation states of g-C3N4/BiVO4 composite sample. UV–Vis DRS spectroscopy analysis revealed that the composite (2.08 eV) sample had a reduced bandgap compared to other samples. The photocatalytic properties of the prepared samples were tested in the presence of organic methylene blue (MB) and antibiotic tetracycline (TC) pollutants under visible light illumination. The hybrid composite catalyst exhibited enhanced photocatalytic degradation efficiency of MB (88%) and TC (89%) pollutants at elevated rate constants of 0.0128 and 0.01174 min−1, respectively. The improved catalytic performance of the composite catalyst is due to the heterojunctions between g-C3N4 and BiVO4 that successfully reduced the rate of charge carrier recombination in the catalyst system. Scavenger experiments revealed that O2●— and h+ radicals played a main role in the degradation of the chemical pollutants. The developed g-C3N4/BiVO4 heterostructured catalyst is a suitable candidate for removing contaminants from industrial wastewater because of its facile fabrication and exceptional photocatalytic activity under visible light irradiation.

Designing of a magnetically recoverable (Ce+3, +4/Fe+2. Fe+3) oxide@ 2D g-C3N4 surface for enhanced photo-Fenton catalytic degradation of Bismarck-Brown R and Congo red dyes: kinetics, optical properties,and mechanistic pathway studies

ABSTRACT Co-precipitation-assisted hydrothermal synthesis was employed to synthesize Fe3O4/CeO2 nanohybrids over 2D g-C3N4 (CF@GCN) for photo-Fenton catalytic degradation of Bismarck brown R (BBR) and Congo Red (CR) dyes. Initially, Fe loading was deployed in CF@GCN with different sets of molar ratios of Fe against the 1 mole of Ce (Ce: Fe=1:0.2-1). Among different sets, the one with 0.8 moles of Fe against the 1 mole of Ce (C1F0.8@GCN) performed excellently for BBR and CR dye degradation via aiding in the photo-Fenton process. Morphological, structural, compositional, and electronic states of the final nanocomposite were evaluated using powder X-ray diffraction, transmission electron microscopy/high-resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. BET analysis of the final nanocomposite showed an excellent surface area of 56.76 m2g−1, allowing for effective degradation. UV–vis spectrophotometry, UV-DRS, and PL (photoluminescence) techniques were performed to monitor the optical properties of the final nanocomposite. Taulc’s plots estimated the band gaps of catalysts, and the final nanocomposite’s band gap was 2.2 eV, which was key for capturing photons from the light source and functioning the degradation process. Further, operating parameters such as catalyst dose, dye concertation, pH, H2O2 dose, and contact time studies were done with the final nanocomposite. C1F0.8@GCN degraded BBR up to 94.5 % within 30 minutes with a first-order rate constant of 0.09747 min−1 and CR dye up to 97.7 % within 45 minutes with a first-order rate constant of 0.07391 min−1. All results supported a nanocomposite of Fe3O4 nanoparticles and CeO2 nanorods grown over 2D g-C3N4 sheets. As predicted, composing Fe3O4 sped up catalyst recovery. Also, the final nanocomposite’s dye degradation rate was consistent till the 6th run. So, the study proposes a cost-effective plan for dealing with organic water contaminants like hazardous dyes.

Bimetal Cu and Fe modified g-C3N4 sheets grown on carbon skeleton for efficient and selective photocatalytic reduction of CO2 to CO

Excessive consumption of fossil fuels leads to resource shortages and the greenhouse effect. In order to solve these problems, the conversion of CO2 to fuel using photocatalytic technology has attracted extensive attention. In this work, Cu and Fe bimetallic modified g-C3N4 sheets grown on carbonized pomelo peels (Cu/Fe-CNC) for photocatalytic reduction CO2 to CO were synthesized via chemical vapor co-deposition (CVD) method. The modification by Cu and Fe bimetallic has enhanced the transfer and separation efficiency of charge carrier and increased surface reaction sites, thereby significantly enhancing the CO yield. Compared with the bulk g-C3N4, the reduction yield of CO2 to CO is increased by 3 times and compared with C3N4 grown on carbonized pomelo peel (CNC), it increased by 2 times. And Cu/Fe-CNC can achieve 100 % reduction of CO2 to CO in the photocatalytic system. Furthermore, the Cu/Fe-CNC has excellent stability in 5 cycle experiments. This work, from a new perspective, assists in developing high active g-C3N4-based photocatalysts to achieve the efficient and selective CO2 to CO reduction.