- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fabrication of novel 1D/2D V2O5/g-C3N4 composites as Z-scheme photocatalysts for CR degradation and Cr (VI) reduction under sunlight irradiation
摘要： Photocatalytic materials for environmental remediation of organic pollutants and heavy metals require not only a strong visible light response and high photocatalytic performance, but also the regeneration and reuse of catalysts. In this work, 1D/2D V2O5 nanorods/g-C3N4 nanosheets (VONRs/CNNs) composites were prepared by a facile impregnation method and employed in the degradation of a Congo red (CR) and reduction of Cr (VI) under sunlight irradiation. The as-prepared samples were studied by several characterization techniques including XRD, SEM, TEM, EDS, XPS, FTIR, UV-vis DRS and PL. Results revealed that the interface interaction between VONRs and CNNs was recognized via V2O5 nanorods loading on the surface of g-C3N4 nanosheets, improving the separation and transfer of photogenerated electron-hole pairs and restraining the recombination rate of charge carriers. As a result, the photocatalytic activity of the composites was enhanced in comparison with pure CNNs and VONRs. The photocatalytic efficiency of optimal composite (4-VONRs/CNNs) for the removal of CR (Cr (VI)) was about 9.33 (4.22) and 73.52 (19.2) times higher than that of pure CNNs and VONRs, respectively. Meanwhile, the 4-VONRs/CNNs exhibited good photocatalytic stability in recycling experiments. Such enormous enhancement in photocatalytic performance was predominantly ascribed to the efficient separation and transfer of photogenerated electron-hole pairs at the VONRs/CNNs interface imparted through the direct Z-scheme charge carrier migration mechanism. Moreover, the energy band structure and the quenching effects of different scavengers demonstrated that the electrons of CNNs and holes of VONRs with higher oxidizability and reducibility are the real participants in photocatalytic reactions.
关键词： g-C3N4 nanosheets,Z-scheme mechanism,Composites,Photocatalytic activity,V2O5 nanorods,1D/2D heterojunction
更新于2025-09-10 09:29:36
-
Improved fluorescence test of chromium (VI) in aqueous solution with g-C3N4 nanosheet and mechanisms
摘要： g-C3N4 nanosheet has been modified by secondary calcination at 550 °C and HNO3 treatment for effectively testing Cr(VI) in aqueous solution via the fluorescence decay according to the inner filter effects proved by the nearly-unchanged time-resolved decay process. The improved fluorescence test performance is attributed to the promoted adsorption of Cr(VI) on resulting g-C3N4 by increasing surface area and the surface positive charge sites. The limit of detection (LOD) is 0.3 μM, which is confirmed by the Stern-Volmer equation with the linear range of 1.0–100.0 μM versus the fluorescence intensity on the optimized conditions of pH = 3 and excitation wavelength of 350 nm. Moreover, at the low-concentration range of 0.2–5.0 μM, it is well linear to the fluorescence intensity by the double logarithmic plot, with the LOD of 0.06 μM. This work provides a feasible route to synthesize g-C3N4-based nanomaterials for effectively detecting Cr(VI) in the solution.
关键词： Secondary calcination,g-C3N4 nanosheet,Cr(VI) testing,HNO3 treatment,Fluorescence decay
更新于2025-09-10 09:29:36
-
Self-sacrifice transformation for fabrication of type-I and type-II heterojunctions in hierarchical BixOyIz/g-C3N4 for efficient visible-light photocatalysis
摘要： Construction of semiconductor heterojunction with hierarchical architectures is highly effective for improving photocatalytic performance. Different heterojunction types with distinct mechanisms lead to different photocatalytic activity enhancement level, and thus the control on heterojunction type is meaningful. Herein, we achieve the fabrication of a series of different types of hierarchical heterojunctions in BixOyIz/g-C3N4, namely, g-C3N4/BiOI, g-C3N4/Bi4O5I2, and g-C3N4/Bi5O7I. g-C3N4/BiOI is prepared by a direct precipitation method, and g-C3N4/Bi4O5I2 and g-C3N4/Bi5O7I are obtained by in situ calcination transformation of g-C3N4/BiOI at different temperature. Among them, g-C3N4/BiOI and g-C3N4/Bi4O5I2 are type-I heterojunction, and g-C3N4/Bi5O7I belongs to type-II heterojunction. The photocatalyitc activity is surveyed by decomposition of diverse industrial contaminants, including methyl orange, bisphenol A and tetracycline hydrochloride under visible light irradiation (λ > 420 nm). It is found that g-C3N4/Bi5O7I shows largely enhanced photodegradation performance compared to g-C3N4/BiOI and g-C3N4/Bi4O5I2. The much higher photocatalytic activity of g-C3N4/Bi5O7I is attributed to the enhanced specific surface area, more efficient charge separation and surface transfer efficiency and increased density of charge carriers owing to the formation of type-II heterojunction. The study provides a reference for in situ fabrication of hierarchical photocatalysts with diverse heterojunction types for optimizing photocatalytic activity.
关键词： g-C3N4,Bi5O7I,heterojunction,BiOI,Bi4O5I2
更新于2025-09-10 09:29:36
-
A green one-pot approach for mesoporous g-C3N4 nanosheets with in situ sodium doping for enhanced photocatalytic hydrogen evolution
摘要： Synchronous nano-structuring and element-doping of g-C3N4 were realized via a green one-pot approach to improve its photocatalytic activity. Na-doped mesoporous g-C3N4 nanosheets of ~5 nm in thickness were facilely synthesized by calcining a mixture of dicyandiamide and sodium chloride. NaCl not only serves as a con?ning-reactor to con?ne the growth of g-C3N4 into mesoporous nanosheets, but also acts as a sodium source for Na-doping. The nanosheets own greater speci?c surface area, stronger optical absorption and lower recombination of photo-induced electron-hole pairs than bulk g-C3N4, and exhibit an excellent visible-light photocatalytic hydrogen evolution ef?ciency which is about 13 times that of bulk g-C3N4. Moreover, the thermostable and hydrosoluble NaCl is simply removed and recycled by water and then directly reused in a new synthesis, making the process to be environmental-friendly and sustainable.
关键词： g-C3N4,Sodium chloride,Photocatalytic hydrogen evolution,Sodium doping,Mesoporous nanosheet
更新于2025-09-10 09:29:36
-
Visible-light photocatalytic fuel cell with Z-scheme g-C3N4/Fe0/TiO2 anode and WO3 cathode efficiently degrades berberine chloride and stably generates electricity
摘要： A visible-light Z-scheme g-C3N4/Fe0/TiO2 anodic catalyst was tested with cathodic WO3 in photocatalytic Fuel Cell (PFC) that efficiently degrades berberine chloride and simultaneously generate electricity at pH 2,5,7 and 13. The Stainless-steel mesh electrodes loaded with prepared catalyst were irradiated by visible-light in single chamber PFC. The highest removal of berberine Chloride, cell voltage, and power density were 91%, 0.8 V, and 16.4 W/m2 at a current density of 2.02 mA/cm2, respectively after 90 min irradiation in 0.05 M Na2SO4 electrolyte, with 10 ? external resistance. The impacts of pH and initial concentration of BEC on photocatalytic degradation and cell voltage were evaluated. The cell current density is enhanced while the photocatalyst activity increased. The constructed PFC maintained high-performance after 5 uses. Its use in degrading wide spectrum refractory pollutants and generate electricity is expected for the proved catalyst design, paired electrodes and high PFC performance for practical wastewater treatment.
关键词： Electricity generation,WO3,Visible-light,g-C3N4/Fe0/TiO2,Photocatalytic Fuel Cell,Berberine Chloride,Z-scheme
更新于2025-09-10 09:29:36
-
Fabrication of Ag3VO4 decorated phosphorus and sulphur co-doped graphitic carbon nitride as a high-dispersed photocatalyst for phenol mineralization and E. Coli disinfection
摘要： In this work, we have successfully anchored Ag3VO4 (AV) onto P and S co-doped g-C3N4 (PSGCN) to prepare high-dispersible AV/PSGCN photocatalyst via a deposition-precipitation method. The P and S co-doped g-C3N4 was synthesized via thermal polycondensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. AV/PSGCN was characterized using various spectral techniques. The atomic force analysis indicated that the thickness of AV/PSGCN was less than 3.0 nm. The zeta potential and Tyndall effect experiments ascertained formation of the well-dispersed suspension of AV/PSGCN in water. The co-doping resulted in lowering optical band gap of g-C3N4. The photoluminescence and electrochemical impedance analysis indicated suppression in recombination of photogenerated electron and hole pairs in AV/PSGCN. The photodegradation of phenol followed pseudo-first order kinetics. Hydroxyl radicals and holes were the two main reactive species for photodegradation of phenol. The COD, HPLC and LC-MS analyses confirmed mineralization of phenol in 6 h. Unlike conventional slurry type photo-reactors, AV/PSGCN was not magnetically agitated during photocatalytic reactions. AV/PSGCN exhibited significant antibacterial activity for E.Coli disinfection. The photodegradation of phenol and bacterial disinfection occurred through hole and hydroxyl radical formation mechanism.
关键词： Phenol degradation,Enhanced photocatalytic activity,Heterojunction formation,Ag3VO4,Antibacterial activity,Co-doped g-C3N4
更新于2025-09-10 09:29:36
-
Effective protect of oxygen vacancies in carbon layer coated black TiO2-x/CNNS hetero-junction photocatalyst
摘要： Carbon layer coated black TiO2-x/g-C3N4 nanosheets (C@TiO2-x/CNNS) heterojunction photocatalysts were successfully prepared via a polydopamine dopamine carbonization route for the first time. It was found that the hydrogen evolution rate of C@TiO2-x/CNNS was 417.2 μmol h-1 g-1 under visible light irradiation, which was much higher than that of other prepared photocatalysts in solar water splitting process at the same conditions, and obvious decrease in catalytic activity can be observed after three recycles. The formation of carbon layer on the surface of TiO2-x can effectively protect Ti3+ and oxygen vacancies (Ovs) from oxidation by air and dissolved O2, afterwards much more Ti3+/Ovs are exsited, which can serve as charge carrier traps to inhibit the recombination of light-excited electrons-holes. Therefore, C@TiO2-x/CNNS showed a highly conductivity, rapidly effective electron-hole separation and lower transmission resistance comprehensive consideration of the advantages of carbon layer and hetero-junction, which are of great benefit to the improvement of photocatalytic performance. Hence, a new catalytic tactic namely layer-protection effect was founded and this strategy for boosting hydrogen evolution and protection Ti3+/Ovs may give us some hints on the design of photocatalytic systems.
关键词： black TiO2,visible light H2 evolution,g-C3N4 nanosheet,carbon layer protect oxygen vacancy
更新于2025-09-10 09:29:36
-
Recyclable Visible Light-driven O-g-C3N4/GO/N-CNT Membrane for Efficient Removal of Organic Pollutants
摘要： Organic pollutants are harmful to human health, which creates a global need for the development of novel and effective materials for efficiently removing contaminants. Accordingly, the efficient visible light-driven heterostructured membrane combined with oxygen-modified monolayer g-C3N4, graphene oxide, and nitrogen-doped CNT (O-g-C3N4/GO/N-CNT) was successfully fabricated through electrostatic interactions and subsequent vacuum filtration. The results suggested that the O-g-C3N4/GO/N-CNT membrane exhibited higher degradation rate than that of O-g-C3N4/GO and pure O-g-C3N4 under visible-light exposure. This enhanced photocatalytic performance was attributed to the introduction of GO and N-CNT, which acted as electronic acceptors for monolayer O-g-C3N4 that effectively inhibited recombination of photogenerated electron-hole pairs, thus enhancing visible light photocatalytic activity. Furthermore, the enrichment and degradation rate of O-g-C3N4/GO/N-CNT membranes were demonstrated for tetracycline hydrochloride, which was found up to 96.64% and 94.30%, respectively, and no distinct enrichment or catalytic activity reduction was observed when their reusability was measured. These results suggested that these recyclable O-g-C3N4/GO/N-CNT membranes provide a new strategy for the highly efficient removal of environmental pollutants.
关键词： O-g-C3N4/GO/N-CNT heterostructured membrane,Organic contaminants,Recyclable,Enhanced Photocatalytic performance,Enrichment
更新于2025-09-10 09:29:36
-
Phosphorus-doped isotype g-C3N4/g-C3N4: an efficient charge transfer system for photoelectrochemical water oxidation
摘要： Constructing isotype g-C3N4/g-C3N4 heterojunction is an approach to improve the efficiency of g-C3N4 towards solar-assisted oxidation of water. Such functional configuration can effectively overcome the intrinsic drawback of rapid charge recombination of g-C3N4. Here, a modified g-C3N4, with homogeneous phosphorus doping, is prepared in this work through a phosphide-involved gas phase reaction. The resulting P-g-C3N4 displays altered electronic structure, including upshifted band edge potential, narrowed band gap and improved electronic conductivity. These features allow P-g-C3N4 as an outstanding candidate to form isotype junction with pristine g-C3N4. As expected, the accelerated charge separation and migration in target junction is validated by various measurements. The isotype g-C3N4/P-g-C3N4 heterojunction achieves a optimized photocurrent as high as 0.3 mA·cm-2 at 1.23 V vs RHE (AM 1.5G, 100 mW·cm-2), representing 8-fold’s enhancement compared with pristine g-C3N4. The present strategy for constructing g-C3N4-based isotype heterojunction networks is found effective for large-scale manufacturing.
关键词： phosphorus doping,g-C3N4,charge transfer,isotype heterojunction,photoelectrochemical
更新于2025-09-10 09:29:36
-
2D-Bi<sub>2</sub>MoO<sub>6</sub>/2D-g-C<sub>3</sub>N<sub>4</sub> nanosheet heterojunction composite: synthesis and enhanced visible light photocatalytic mechanism
摘要： In this study, a novel 2D Bi2MoO6 nanosheet/2D g-C3N4 nanosheet heterojunction composite was fabricated through hydrothermal strategy. Afterwards, physicochemical properties of the composite were systematically detected by series of measurements. In addition, photocatalytic activity was evaluated by degradation of Rhodamine B, methylene blue, Amido black 10B and malachite green. Results showed that Bi2MoO6/g-C3N4 played higher photocatalytic efficiency than that of pristine Bi2MoO6 and g-C3N4 sample under visible irradiation. This phenomenon could be attributed to the combination of Bi2MoO6 and g-C3N4 as well as unique 2D/2D heterostructure. Also, the as-fabricated Bi2MoO6/g-C3N4 composite possessed higher surface area, narrower band gap energy, larger electron transport capability and longer charge carrier lifetime. Furthermore, the enhanced visible light driven photocatalytic mechanism was proposed and confirmed, which was mainly ascribed to the Z-scheme structure. That was, the photogenerated electrons (e-) in the CB of Bi2MoO6 and photogenerated holes (h+) in the VB of g-C3N4 would combine with each other quickly, so that the e- in the CB of g-C3N4 and h+ in the VB of Bi2MoO6 participated in reduction and oxidation reactions, respectively. Also, this composite exhibited superior physicochemical stability. Hence, it would be applied in advanced wastewater treatment.
关键词： Nanosheet heterojunction,Bi2MoO6/g-C3N4,Visible light photocatalysis,Z-Scheme,2D/2D
更新于2025-09-09 09:28:46