3N4 Photocatalyst Research Articles

High-efficiency and stable Z-scheme heterojunction of Co9S8 anchored by g-C3N4 for peroxymonosulfate activation

Photocatalytic technology and peroxymonosulfate (PMS) based advanced oxidation technology have been proven to be simple and effective strategies for recalcitrant organic pollutants degradation. In this work, we designed and prepared a coupled photocatalytic and advanced oxidation system for sulfamethazine (SMR) antibiotics degradation. Firstly, a series of Z-scheme Co9S8/g-C3N4 heterojunction photocatalysts are prepared by a simple two-step method and further work as PMS activators. The prepared Co9S8/g-C3N4 photocatalysts exhibit a great improvement in electron-hole pairs migration and visible-light response due to heterojunction formation. In addition, the g-C3N4 acts as a substrate to anchor the Co9S8 nanoparticle, which suppresses the Co9S8 leaching and prevents the Co9S8 oxidation. Consequently, the Co9S8/g-C3N4/PMS system displayed an improved SMR degradation ability (93 % for Co9S8/g-C3N4/PMS vs. 86 % for Co9S8/g-C3N4). After the fourth cyclic degradation experiment, the Co9S8/g-C3N4/PMS system still maintained a comparatively high degradation rate. Considering its good properties and better degradation performance, we propose that the synergistic effect of photocatalytic technology and PMS possess a promising prospect for application in environmental treatment.

Construction of visible-light-induced Fe2O3/g-C3N4 nanocomposites for the enhanced degradation of organic dyes: Optimization of operative parameters

This research aims to develop the highly promising Fe2O3/g-C3N4 photocatalyst through hydrothermal techniques to cope with the elevated amounts of bromophenol blue (BPB) dye in wastewater. The morphological studies were carried out by SEM analysis, while the crystallinity, structural behavior, and oxidation states of the prepared materials were determined by XRD, FTIR, and XPS analysis. The hydrodynamic size, surface area, and magnetic characteristics of the constructed materials were assessed through DLS, BET, and VSM analysis. The effectivity of the synthesized Fe2O3 and Fe2O3/g-C3N4-30 photocatalysts was appraised by the abatement of BPB under visible light radiation for 48 min. The results have shown an excellent degradation efficacy of Fe2O3/g-C3N4-30 photocatalyst with 98.39 % of BPB removal and a rate constant of 0.0757 min−1, which was much higher than Fe2O3 photocatalyst with 79.64 % of removal and a rate constant of 0.0335 min−1 under optimum conditions. The enhancement in degradation efficiency of the Fe2O3/g-C3N4-30 was due to the large surface area of Fe2O3/g-C3N4-30 (106.94 m2/g) as a result of g-C3N4 inclusion in the material, while the pure Fe2O3 unveiled a surface area of 89.67 m2/g. The impact of different reaction parameters on BPB degradation was also investigated, while the contribution of free radicals was corroborated through radical trapping experiments. The Fe2O3/g-C3N4-30 exhibited tremendous stability for repeated applications, with a loss of 8.03 % in efficiency after five consecutive experiments because of its easy magnetic separation. The experimental results have shown that synthesized Fe2O3/g-C3N4-30 photocatalysts could be used for the effective degradation of BPB from wastewater.

Synergistic role of indium doping and g-C3N4 reinforcement in boosting the visible light-triggered rhodamine B and diclofenac sodium salt degradation over rare earth molybdate

Designing and fabricating cost-efficient and eco-friendly photocatalysts for removing organic pollutants from wastewater streams is a crucial research objective for effectively managing industrial effluents to tackle environmental sustainability issues. In this study, we prepared bare cerium molybdate (Ce2(MoO4)3, M1) and indium-doped cerium molybdate (In- Ce2(MoO4)3, M2) photocatalysts via a hydrothermal method. We then synthesized a nanocomposite of In- Ce2(MoO4)3 (M3) with the promising material graphitic carbon nitride (g-C3N4) using an ultrasonication approach. The synthesized photocatalysts were effectively applied to degrade the Rhodamine B dye and diclofenac sodium salt (a drug) from synthetic industrial wastewater through a photocatalysis approach. The impact of indium (In3+) doping on the bare (Ce2(MoO4)3 and the strong interaction between the (In-Ce2(MoO4)3 and g-C3N4 nanosheets were analyzed through physical and electrochemical techniques, including SEM, EDS, XRD, FTIR, UV–Vis spectroscopy, and EIS analysis. The comprehensive photocatalytic degradation of dye and the drug via first-order kinetic parameters under visible light irradiation for all the prepared catalyst samples was evaluated. The nanocomposite In-Ce2(MoO4)3/g-C3N4 exhibited excellent photocatalytic activity, degrading the maximum amount of RhB dye and drug (RhB:96 %, drug:87 %) in 90 min with a higher rate constant (k) compared to In-Ce2(MoO4)3 (RhB:69 %, drug:56 %) and Ce2(MoO4)3 (RhB:56 %, drug:38 %). Furthermore, the In-Ce2(MoO4)3/g-C3N4 samples produced a 7-fold and 3-fold increase in transient photogenerated current response compared to pristine Ce2(MoO4)3 and In-Ce2(MoO4)3 samples, respectively. These findings pave the way for synthesizing an economical, versatile, and efficient In-Ce2(MoO4)3/g-C3N4 photocatalyst to eliminate pollutants from industrial wastewater streams and boost environmental sustainability.

Oxygen Vacancies Regulated S-Scheme Charge Transport Route in BiVO4-OVs/g-C3N4 Heterojunction for Enhanced Photocatalytic Performance.

Oxygen vacancies (OVs) are widely considered as active sites in photocatalytic reactions, yet the crucial role of OVs in S-scheme heterojunction photocatalysts requires deeper understanding. In this work, OVs at hetero-interface regulated S-scheme BiVO4-OVs/g-C3N4 photocatalysts are constructed. The Fermi-level structures of BiVO4 and g-C3N4 lead to a redistribution of charges at the heterojunction interface, inducing an internal electric field at the interface, which tends to promote the recombination of photogenerated carriers at the interface. Importantly, the introduction of OVs induces defect electronic states in the BiVO4 bandgap, creating indirect recombination energy level that serves as crucial intermediator for photogenerated carrier recombination in the S-scheme heterojunction. As a result, the photocatalytic degradation rate on Rhodamine B (RhB) and tetracyclines (TCs) for the optimal sample is 10.7 and 11.8 times higher than the bare one, the photocatalytic hydrogen production rate is also improved to 558 µmol g-1 h-1. This work shows the importance of OVs in heterostructure photocatalysis from both thermodynamic and kinetic aspects and may provide new insight into the rational design of S-scheme photocatalysts.

Anti-cytoplasmic performance of Zn/g-C3N4 photocatalysts in the battle against microcystis aeruginosa

Cyanobacterial blooms pose a serious challenge to ecosystems and human health. Photocatalysis, as an advanced green oxidation technology, has potential applications in cyanobacteria removal. In this paper, Zn/g-C3N4 photocatalysts with different mass ratios were prepared for algal inactivation. In 3 h, the best performance comes from the experiment using 10 % Zn/g-C3N4 photocatalyst, which inactivated 80 % of microcystis aeruginosa (9×106 ∼ 10×106 cells/mL) when exposed to visible light. Secondly, the potential mechanism of the photocatalytic inactivation of microcystis aeruginosa was proposed in combination with the generation of reactive oxygen species and the leakage of the algal cell contents. The photocatalyst first covered the surface of the algal cells to stop their movement; then the catalyst was excited under light and destroyed the outer protective structures of the cells (cell membrane, cell wall, and organic membrane, etc.) through the action of reactive oxygen species (1O2 and •OH) generated by Zn/g-C3N4, leading to structural changes in the outer layer of the cells. And then photocatalytic oxidation of the intracellular cytoplasm led to the loss of its physiological functions (via losing of inorganic ions and non-electrolytes, etc.). Finally the cell is inactivated or decomposed. This understanding may provide theoretical and practical implications for the prospects of harmful algal control.

Construction of magnetically separable S-scheme BiFeO3/Cl-g-C3N4 heterostructure photocatalyst for simultaneous removal of Cr(Ⅵ) and tetracycline in aqueous solution: Performance and mechanism insight

A green, efficient and recyclable magnetic BiFeO3/Cl-g-C3N4 photocatalyst was prepared for the simultaneous removal of Cr(Ⅵ) and tetracycline (TC) from water by wet chemical and thermal synthesis methods. Experimental results revealed that BiFeO3/Cl-g-C3N4 achieved a removal efficiency of 96.1 % for Cr(Ⅵ) and 98.2 % for TC under visible light irradiation for 50 min at pH 6. The results of the work function, differential charge density, UV–vis DRS, PL, PC and EIS tests indicate the formation of S-scheme heterojunctions between BiFeO3 and Cl-g-C3N4, which exhibits superior carrier separation and migration efficiency. The evidence for interfacial charge transfer from BiFeO3 to Cl-g-C3N4 within BiFeO3/Cl-g-C3N4 was further corroborated by means of ISIXPS, EPR and KPFM. Moreover, calculations of the density of states demonstrate that the introduction of Cl enhances the reduction capability of BiFeO3/Cl-g-C3N4. Results from ESR tests and trapping experiments has demonstrated that the singlet oxygen (1O2) and electrons are the primary active species. Furthermore, the high removal rates of TC and Cr(VI) from industrial wastewater and groundwater, coupled with the lower ecotoxicity of TC degradation intermediates, indicate that BiFeO3/Cl-g-C3N4 has the potential for practical applications. After five cycles, the BiFeO3/Cl-g-C3N4 still removed 90.5 % of TC and 96 % of Cr(Ⅵ).

Ultra-fine carbon decorated TiO2/C/g-C3N4 hybrid for strong physical adsorption and efficient photodegradation of pollutants

Enhancement in the visible light absorption and efficient interfacial charge transfer is crucial for optimizing photocatalytic efficiency in the degradation of pollutants such as methyl orange (MO) and formaldehyde. This study focuses on the properties of a TiO2/C/g-C3N4 hybrid efficient photocatalyst is developed by employing an air calcination method to deposit graphitic nitride (g-C3N4) onto a carbon-modified TiO2 surface. The characterization techniques, including high-resolution transmission electron Microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), were used to provide a comprehensive understanding of the material’s structural, morphological, thermal, and chemical properties. This hybrid catalyst is specifically engineered for the efficient decomposition of methyl orange (MO) and formaldehyde, demonstrating a significant increase in photocatalytic activity. The TiO2/C/g-C3N4 photocatalyst also exhibits an enhanced specific surface area of 181.2 m2/g, which facilitates increased physical adsorption and photo-catalytic active sites. Experimental results confirm that this catalyst effectively adsorbs MO physically even in the dark without degradation. Combining physical and photo-catalytic functions, this catalyst degrades 94 % of MO within 180 min with the initial concentration 0.2 mol/L of MO, and achieves almost 100 % decolorization of MO under visible light irradiation. Notably, the catalyst retains its high activity after 4 cycles of MO degradation, underscoring its durability and consistent performance. Additionally, the hybrid catalyst features a staggered type-II energy level configuration, which effectively enhances charge separation and boosts photocatalytic efficacy. The incorporation of an ultrafine carbon layer further augments electron mobility towards the surface, crucial for effective catalytic reactions. This study paves the way for future development of highly efficient photocatalytic materials for environmental purification.

Construction of marigold-like ZnIn2S4@Tb-g-C3N4 heterojunction for facilitating photocatalytic degradation of tetracycline and tylosin under simulated solar irradiation

Due to the high biological toxicity and the propensity to induce antibiotic resistance, the treatment of antibiotic wastewater has consistently posed a formidable challenge. The semiconductor photocatalysts can efficiently and completely remove antibiotics from the wastewater to repair the water environment. Therefore, a novel ZnIn2S4/Tb-g-C3N4 (ZIS/TCN) photocatalyst was successfully synthesized in this paper and its ability to efficiently degrade antibiotics has been verified. The optimized 150ZIS/TCN photocatalyst showed excellent photocatalytic performance and stablility toward the degradation of tetracycline (TC) and tylosin (TYL) under sunlight simulated with a xenon lamp. Compared with pristine g-C3N4 and ZnIn2S4, the 150ZIS/TCN exhibited superior degradation performance for TC (TYL)，about 3.2 (2.1) and 1.8 (1.5) times higher than them. Based on density functional theory (DFT) calculations and experimental characterization test results, it was confirmed that the Tb doping effectively regulates the intrinsic electric field and visible light absorption capacity. This study unveils the degradation mechanism of ZIS/TCN photocatalysis and provides an effective pathway for enhancing photocatalytic degradation through rare earth doping.

Enhancement of photocatalytic degradation of ciprofloxacin via constructing conductive matrix

The application of heterogeneous photocatalysts is severely limited by the high charge transfer resistance (Rct). BiVO4/g-C3N4 photocatalysts were prepared and loaded on the conductive matrix material carbon paper (CP) to reduce electron transfer resistance and improve the photocatalytic performance. The Rct of BiVO4/g-C3N4@CP was remarkedly reduced by 94.3 % compared to the photocatalysts on the oil paper (BiVO4/g-C3N4@OP), while the photocurrent density increased by 5.5 times. The utilization efficiency of light energy and separation of photoelectrons and holes were improved with CP due to its ability to facilitate long-distance transfer of photoelectrons. Consequently, the photocatalytic degradation performance of BiVO4/g-C3N4@CP was enhanced by a 26.1 % improvement in ciprofloxacin (CIP) degradation efficiency. Quenching experiment, LC-MS analysis and DFT calculation revealed that piperazine ring opening and C-F cleavage were the major pathways for CIP degradation with BiVO4/g-C3N4@CP.

The coexistence of highly dispersed Pt2+ and Pt0 co-catalysts on chemically oxidized g–C3N4 via metal-support interaction: The effect of reduction time on Pt species and hydrogen evolution of Pt/g-C3N4 photocatalysts

Platinum (Pt) cocatalyst greatly enhances the photoactivity of the graphitic carbon nitride (g-C3N4) photocatalyst for photocatalytic H2 evolution where the Pt properties are critical to determine the photocatalytic activity. In this study, highly dispersed Pt was successfully loaded onto chemically oxidized g–C3N4 (OCN) via a hydrogen reduction process over different reduction time. OCN photocatalysts containing highly dispersed Pt2+/Pt0 exhibited outstanding charge separation efficiency and photocatalytic performance. Symmetrical –CO groups on the OCN surface specifically interacted with atomic Pt2+, and the Pt2+ atoms were stably reduced to Pt0 atoms along with the generation of –OH groups over time. The coexistence of Pt0 and Pt2+ promoted superior photocatalytic performance because the photoinduced charge transfer was facilitated by the Pt0 atoms, which was evidenced by the DFT calculation and the EIS, PL, and photocurrent response results. Consequently, after the 24 h reduction, the highly stable and active Pt2+/Pt0 atoms were effectively distributed over OCN, resulting in the highest HER activity at 4091.3 µmol g−1 h−1.

AgCl co-catalyst modified g-C3N4 nanosheets for highly efficient photocatalytic hydrogen evolution

This article uses a co-precipitation method to prepare AgCl/g-C3N4 photocatalysts, and the different loading amounts of AgCl on the g-C3N4 surface photocatalysts have a major effect on the efficiency of photocatalysis. AgCl/g-C3N4 photocatalysts can reduce charge transfer efficiency and enhance photocatalytic performance by loading a significant amount of AgCl onto their surface, which results in a wide interface contact area, excellent charge transfer efficiency, and an increase in numerous surface active sites. In ideal circumstances, 15 % AgCl/g-C3N4 (15 % AgCl/CN) photocatalyst exhibits visible light in triethanolamine aqueous solution (λ > 420) the hydrogen production is as high as 721.34 μmol h−1 g−1 is 15.6 times greater than traditional g-C3N4 photocatalysts. The result show that photocatalysts based on g-C3N4 are capable of producing hydrogen with good efficiency.

Facile construction of ZnWO4/g-C3N4 heterojunction for the improved photocatalytic degradation of MB, RhB and mixed dyes

This study presents the construction of binary ZnWO4/g-C3N4 nanocomposite via a facile hydrothermal approach to enhance the photocatalytic performance under the visible light irradiation. The proposed ZnWO4/g-C3N4 nanocomposite photocatalyst shows excellent photodegradation towards organic dyes, such as methylene blue (MB) and rhodamine B (RhB). The optimal loading of ZnWO4 and g-C3N4 leads to the synergistic effect which plays a predominant role in inhibiting the fast electron-hole pairs recombination rate at the interface of ZnWO4/g-C3N4 photocatalyst. The degradation rates of MB and RhB is achieved around 92.9 % and 88.8 % under the visible light irradiation for 120 min. According to our findings, the radical quenching experiments suggested that the ●OH radicals played a positive impact in the photodegradation process. Since, our proposed photocatalyst exhibit superior photocatalytic activity towards the individual MB and RhB degradation. The ZnWO4/g-C3N4 photocatalyst were further applied to demonstrate the degradation of mixed dyes (MB and RhB) at an irradiation time of 180 min. In the mixed dye solution, the ZnWO4/g-C3N4 photocatalyst achieved a highest reaction rate of 0.010 min−1 for MB and 0.012 min−1 for RhB with the degradation rate of 87.8 % and 83.3 % for RhB and MB, respectively. For the mixed dyes, the radical quenching experiments confirmed that the ●OH radicals are responsible for the fast photodegradation. Additionally, the practicality of the proposed ZnWO4/g-C3N4 photocatalyst towards the degradation of MB, RhB and the mixed dyes were examined in the tap water samples. Furthermore, the plausible photodegradation mechanism of ZnWO4/g-C3N4 photocatalyst was proposed in detail. This study provides a new insight for the simultaneous degradation of mixed chemical pollutants using our proposed ZnWO4/g-C3N4 photocatalyst.

Preparation of Fe2O3/g-C3N4 Photocatalysts and the Degradation Mechanism of NOR in Water under Visible Light Irradiation

Fe2O3/g-C3N4 nano-heterostructures for photocatalytic degradation of NOR (norfloxacin) were successfully prepared by combining co-precipitation and calcination methods. The g-C3N4, Fe2O3, and different composite ratios of Fe2O3/g-C3N4 (FeCNs) were characterized by XRD, SEM, XPS, UV-vis DRS, PL, and electrochemical tests, and the mechanism of photocatalytic degradation of NOR was analyzed. The results indicated that the semiconductor was attached to the surface of g-C3N4 in the form of α-Fe2O3 crystal with good crystalline structure. The composite of Fe2O3 with g-C3N4 increased the specific surface area of the material, effectively reduced the band gap, strengthened the photogenerated e−/h+ pair separation, and improved the photocatalytic performance of the composite. The photocatalytic degradation of NOR was consistent with the quasi-primary reaction kinetic model. Among them, FeCN-25wt% showed the optimal photocatalytic degradation of NOR (72.3%) with the largest degradation rate (k = 0.00900 min−1). The Fe2O3/g-C3N4 composite structure is inferred to be a Z-type heterojunction.

Enhancement of dye treatment efficiency of TiO2/C3N4 photocatalysts synthesized by hydrothermal method

Abstract Using sunlight to generate energy is a trend to establish a sustainable economy while protecting the environment. Photocatalytic breakdown of organic molecules on the surfaces of semiconductors is an important topic of current research. In this study, competent TiO2/g-C3N4 photocatalysts produced by the hydrothermal technique demonstrated outstanding photoactivity. To determine the best-performing photocatalyst, TiO2/g-C3N4 materials were analyzed by using Scanning Electron Microscopy (SEM), X-ray diffraction analysis (XRD), Energy Dispersive X- ray (EDX), Brunauer-Emmett-Teller (BET) analysis, and Differential Reflectance Spectroscopy (DRS). XRD results indicate that the addition of C3N4 increases the ratio of TiO2 Anatase. Optical studies unveiled a significant reduction in the forbidden band. The experiments using photocatalysis revealed that the action of TiO2/g-C3N4 on methylene blue (MB) dyes exhibited not only momentous photocatalytic performance but also excellent adsorption ability. The result of this study is anticipated to offer a solid basis for the creation and synthesis of cutting-edge materials for applications including the treatment of textile effluent.

Fabrication of SrTiO3 anchored rGO/g-C3N4 photocatalyst for the removal of mixed dye from wastewater: dual photocatalytic mechanism

A metal-free combination of rGO/g-C3N4-coupled SrTiO3 (SRN) ternary nanocomposite prepared via a wet impregnation method for UV–Vis light photocatalytic applications. Various physicochemical properties of the samples were investigated by several spectroscopic techniques including X-ray diffraction (XRD), FT-IR, Raman, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FE-SEM-EDX), high-resolution transmission electron microscopy (HR-TEM), UV–Vis, photoluminescence (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) surface area analysis. The data suggest agglomerated SRT nanoparticles are dispersed and distributed throughout the surface of the rGO sheets and GCN nanostructures. The photocatalytic performance of the SRN towards combined mixed dye and its degradation activities were evaluated towards the most common industrial effluents, Rhodamine B (RhB) and Methylene blue (MB), under UV–Vis light illumination. The results revealed that the degradation efficiency of the SRN photocatalyst shows excellent performance compared with that of the binary composition and the pure SrTiO3 (SRT) sample. The reaction rate constant for RhB was estimated to be 0.0039 min−1 and for MB to be 0.0316 min−1, which are 3.26 (RhB) and 4.21 (MB) times faster than the pure SRT sample. The enhanced degradation efficiency was attained not only by interfacial formation but also by the speedy transportation of electrons across the heterojunction. After 5 runs of the photocatalytic recylic process, the SRN photocatalyst exhibited ultimate stability without structural changes, and no noticeable degradation was observed. The outcomes of the ternary SRN nanocomposite manifest a dual photocatalytic scheme, the photocatalytic enrichment could be caused by the Z-scheme charge transfer process between GCN, SRT, and rGO nanocomposite, which helps effectual charge separation and keeps a high redox potential. From the results, SRN sample provides insight into the integration of an effective and potential photocatalyst for wastewater treatment toward real-time environmental remediation applications.

Fabrication of ternary Bi2S3/BiVO4/g-C3N4 composite material for enhanced photocatalytic degradation of antibiotics

Antibiotic contaminants are known to pose a serious threat to the human health and environment, thus a great deal of effort has been made to develop destruction technologies for antibiotic treatment in the water environment. Photocatalytic oxidation technology is regarded as one of the most promising strategies for decomposing antibiotics from water. In this work, ternary Bi2S3/BiVO4/g-C3N4 composite material is dexterously designed and synthesized to obtain the enhanced photocatalytic performance for tetracycline (TC) degradation via a facile strategy. Therein, the optimal Bi2S3/BiVO4/g-C3N4 material showed the excellent degradation efficiency under visible light irradiation in comparison to the nude g-C3N4 and BiVO4/g-C3N4 photocatalysts, and it can continuously degrade the TC pollutant in 90 min and achieve a degradation percentage of 80.7 %. The designed materials can not only intensify photo-absorption efficiency of g-C3N4 material, but also improve its separation and transfer efficiency of photo-generated charge carriers, which is attributed to the incorporation of BiVO4 and Bi2S3 materials. The active species trapping experiments verified that the superoxide radicals (•O2−) is the main active species, and holes (h+) also played an important role in the Bi2S3/BiVO4/g-C3N4 system. Furthermore, the photoelectrochemical measurement (PEC) clearly demonstrated that the incorporation of BiVO4 and Bi2S3 materials could accelerate the separation and transfer of photo-generated electron and hole pairs. As expected, our present work could spark new inspirations to further develop the efficient photocatalysts for solar energy conversion.

Oxidation of antibiotic micropollutants in various water resources through integration of Bi2WO6 and g-C3N4.

Recently, the hazardous effects of antibiotic micropollutants on the environment and human health have become a major concern. To address this challenge, semiconductor-based photocatalysis has emerged as a promising solution for environmental remediation. Our study has developed Bi2WO6/g-C3N4 (BWCN) photocatalyst with unique characteristics such as reactive surface sites, enhanced charge transfer efficiency, and accelerated separation of photogenerated electron-hole pairs. BWCN was utilized for the oxidation of tetracycline antibiotic (TCA) in differentwater sources. It displayed remarkable TCA removal efficiencies in the following order: surface water (99.8%) > sewage water (88.2%) > hospital water (80.7%). Further, reusability tests demonstrated sustained performance of BWCN after three cycles with removal efficiencies of 87.3, 71.2 and 65.9% in surface water, sewage, and hospital water, respectively. A proposed photocatalytic mechanism was delineated, focusing on the interaction between reactive radicals and TCA molecules. Besides, the transformation products generated during the photodegradation of TCA were determined, along with the discussion on the potential risk assessment of antibiotic pollutants. This study introduces an approach for utilizing BWCN photocatalyst, with promising applications in the treatment of TCA from various wastewater sources.

Constructing multifunctional novel noble-metal free NiS/ZnS/g-C3N4 ternary nanocomposites for highly active superior photocatalytic water splitting

Ultrasound-assisted wet-impregnation approach and cation-exchange hydrothermal method are employed effectively to develop the ternary nanocomposites NiS/ZnS/g-C3N4 (NZ-CN) with promising photocatalytic hydrogen (H2) generation activity. Several analytical techniques are utilized to characterize the as-synthesized NiS/ZnS/g-C3N4 nanocomposites to study their physical and chemical characteristics. The H2 production activity of the synthesized photocatalysts was tested using a 250 W halogen lamp with Na2S (0.25 M) and Na2SO3 (0.35 M) as sacrificial reagents. The optimized NZ-CN7.5% (3% NiS/ZnS/7.5% g-C3N4) catalyst displayed an exceptional H₂ generation rate of 8624 μmol h⁻1 g⁻1, exceeding both, pristine g-C3N4 (by 22.1 times) and 3% NiS/ZnS (by 3 times). This represents the highest reported rate of H₂ evolution for a graphitic carbon nitride (g-C3N4) based ternary nanocomposite under simulated solar radiation. By reusing the used NZ-CN7.5% (3% NiS/ZnS/7.5% g-C3N4) photocatalyst in four consecutive runs, the stability of the catalyst was investigated, and their individual activity in the H2 production activity was assessed. This study provides valuable insights for designing efficient noble metal-free g–C3N4–based photocatalysts, which can significantly contribute to the transition to solar-driven hydrogen generation. Further, we proposed a plausible mechanism for the photocatalytic H2 generation process over the NiS/ZnS/g-C3N4 photocatalyst.

Preferential degradation of ofloxacin on all-organic molecularly imprinted PDI/g-C3N4 photocatalyst via specific molecular recognition

Preferential degradation are urgently needed for detoxification of organic pollutants. Herein, a novel all-organic molecularly imprinted photocatalyst was first constructed by grafting molecularly imprinted perylenediimide (PDI) on graphite-phase carbon nitride (MIP-PDI/g-C3N4) using ofloxacin as template molecule. MIP-PDI/g-C3N4 exhibits higher adsorption capacity for ofloxacin than the non-imprinted counterpart (NIP-PDI/g-C3N4), and shows superior molecular recognition in the mixed solution of ofloxacin and ciprofloxacin. The partition coefficient of MIP-PDI/g-C3N4 for ofloxacin is 3.19 times that for ciprofloxacin, and selection factor of MIP-PDI/g-C3N4 is 1.84 times of NIP-PDI/g-C3N4, suggesting good molecular recognition of MIP-PDI/g-C3N4. The excellent molecular recognition endowed MIP-PDI/g-C3N4 with preferential degradation performance, leading to effective mineralization and detoxification of ofloxacin solution. Most importantly, the preferential degradation mechanism based on molecular recognition was proposed.

Rationally construction of Dy2O3/g-C3N4 heterojunctions with largely enhanced photocatalytic hydrogen evolution activity

In this paper, Dy2O3/g-C3N4 photocatalysts with augmented photocatalytic hydrogen evolution activity were obtained by a pore impregnation method after baking. The samples were evaluated via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Separation and migration efficiency of photogenerated carriers was analyzed using surface photovoltage spectroscopy (SPS), transient photocurrent density (TPR) and electrochemical impedance spectroscopy (EIS). Through low-temperature electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS), nitrogen vacancies were successfully introduced into g-C3N4. All Dy2O3/g-C3N4 samples display more stronger photocatalytic activity than the reference g-C3N4. Notably, 3 % DyO/CN exhibits the highest photocatalytic activity. The average photocatalytic hydrogen evolution rate over 3 % DyO/CN reaches 9.9 mmol·g−1·h−1, which is nearly 3 times of that over the reference sample (3.3 mmol·g−1·h−1). In view of the observations, photocatalytic mechanism of Dy2O3/g-C3N4 heterojunction was rationally proposed.