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Facile preparation of KBiO <sub/>3</sub> /g-C <sub/>3</sub> N <sub/>4</sub> composites with microwave irradiation for photocatalytic hydrogen production
摘要： BACKGROUND: KBiO3/g-C3N4 composites were prepared under microwave irradiation to different weight ratio of KBiO3 (5, 10, 20, 30, 40, 50, 60, 70 80, 90 %wt) using a Mars-6 for 30 min at 100 W. The samples were characterization by XRD, FT-IR, SEM, EDS-Mapping, N2 physisorption and DRS. The photocatalytic activity of the samples was evaluated in the hydrogen evolution reaction. RESULTS: The composites were confirmed by XRD, where was observed that the samples up to 60% of KBiO3 it is easy to identify the characteristic peak of g-C3N4. Composites show that KBiO3 was homogeneously dispersed on g-C3N4 according to what was observed by EDS-Mapping. In the photocatalytic tests was observed that when the concentration of g-C3N4 is greater than KBiO3 but up to a certain limit, there is a higher production of hydrogen. CONCLUSIONS: KBiO3/g-C3N4 composites were prepared successfully with microwave irradiation reaching a good synergy between both materials for hydrogen production reaction. This synergy was improved to the use of microwave that facilitates the dispersion and binding of both materials. The sample with best hydrogen production was 40%KBiO3/60%C3N4 with 698 μmol H2/g, which is about 3 times higher than g-C3N4 and 7 times higher than KBiO3.
关键词： KBiO3/g-C3N4,photocatalysis,hydrogen production,microwave method
更新于2025-09-23 15:23:52
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Revealing the role of kapok fibre as bio-template for In-situ construction of C-doped g-C3N4@C, N co-doped TiO2 core-shell heterojunction photocatalyst and its photocatalytic hydrogen production performance
摘要： For the first time, C-doped g-C3N4@C, N co-doped TiO2 core-shell heterojunction photocatalyst was successfully prepared by an in-situ one-pot hydrothermal bio-template approach, assisted by calcination treatment at 500?°C. Kapok fibre was used as a bio-templates and in-situ C doping in g-C3N4 and TiO2 during the formation of core-shell heterojunction photocatalyst. Moreover, the used of urea as g-C3N4-precursor also contribute to band-gap narrowing by an in-situ carbon and nitrogen doping in TiO2. Various characterisation techniques were employed to understand the effect TiO2 precursor concentration on the evolution of core-shell nanostructure heterojunction photocatalyst that can affect and boost the catalytic activity. The detailed understanding of the concurrent growth of C-doped g-C3N4 (CCN) and C, N co-doped TiO2 mechanism, as well as the formation of core-shell nanostructures heterojunction formation, are also proposed in this study. Our finding indicated that the bio-template core-shell nanostructure heterojunction photocatalysts showed a dramatic increase in photoinduced electron-hole separation efficiency as demonstrated by the photoelectrochemical and photoluminescence analyses. The enhancement in photogenerated charge carrier separation and narrower band gap resulted in superior photocatalytic activities with the highest rate of hydrogen production was recorded by CCN/T-1.5 sample (625.5 μmol h-1 g-1) in methanol aqueous solution. The well-developed interconnected heterojunction formation with appropriate CCN and TiO2 contents in core-shell nanoarchitectures system is a prime factor for the future design of a highly efficient visible-light-driven photocatalyst.
关键词： Bio-template,Heterojunction photocatalyst,Core-shell,Co-doping,Photocatalytic hydrogen production,Visible light
更新于2025-09-23 15:23:52
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Photocatalytic hydrogen production by biomimetic indium sulfide using Mimosa pudica leaves as template
摘要： Biomimetic sulfur-deficient indium sulfide (In2.77S4) was synthesized by a template-assisted hydrothermal method using leaves of Mimosa pudica as a template for the first time. The effect of this template in modifying the morphology of the semiconductor particles was determined by physicochemical characterization, revealing an increase in surface area, decrease in microsphere size and pore size and an increase in pore volume density in samples synthesized with the template. X-ray photoelectron spectroscopy (XPS) analysis showed the presence of organic sulfur (S-O/S-C/S-H) and sulfur oxide species (eSO2, SO3^2-, SO4^2-) at the surface of the indium sulfide in samples synthesized with the template. Biomimetic indium sulfide also showed significant amounts of Fe introduced as a contaminant present on the Mimosa pudica leaves. The presence of these sulfur and iron species favors the photocatalytic activity for hydrogen production by their acting as a sacrificial reagent and promoting water oxidation on the surface of the templated particles, respectively. The photocatalytic hydrogen production rates over optimally-prepared biomimetic indium sulfide and indium sulfide synthesized without the organic template were 73 and 22 mmol g^-1 h^-1, respectively, indicating an improvement by a factor of three in the templated sample.
关键词： Photocatalytic hydrogen production,XPS analysis,In2.77S4,Template-assisted hydrothermal
更新于2025-09-23 15:23:52
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In-situ hydrothermal fabrication of CdS/g-C3N4 nanocomposites for enhanced photocatalytic water splitting
摘要： In this work, a series of CdS/g-C3N4 nanocomposites with varying wt% CdS were prepared via an in-situ hydrothermal synthesis method. 10 wt% CdS/g-C3N4 nanocomposites displayed the highest rate of hydrogen evolution via photocatalytic water splitting. The H2 evolution rate of 10 wt% CdS/g-C3N4 is 21 times greater than pure g-C3N4 and 4 times greater than that of pure CdS. Key factors responsible for the enhanced photocatalytic activity can be attributed to the improved charge separation and increased surface area of CdS/g-C3N4 nanocomposites. These findings may serve as a platform for the fabrication of other photocatalytic multi-material nanocomposites in the future.
关键词： Nanocomposite,Photocatalysis,Solar fuels,Electrical properties,Hydrogen production
更新于2025-09-23 15:22:29
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Introduction of Nitrogen Defects into a Graphitic Carbon Nitride Framework by Selenium Vapor Treatment for Enhanced Photocatalytic Hydrogen Production
摘要： Graphitic carbon nitride (g-C3N4) is a metal-free semiconductor photocatalyst that has attracted significant attention due to its promising application in photocatalytic hydrogen production. However, pristine g-C3N4 suffers from a high recombination rate of photo-generated charge carriers and also has a limited visible-light absorption range, resulting in low photocatalytic activity. Herein, we report on the preparation and testing of a g-C3N4 photocatalyst with tunable nitrogen defects that delivered improved photocatalytic activity. The nitrogen defects were gradually introduced into the g-C3N4 framework by a selenium vapor treatment of pure g-C3N4, which resulted in improved, stable catalytic activity for photocatalytic hydrogen production. Based on the experimental results and DFT calculations, we proposed that the enhanced photoactivity is attributed to the defect state (DS) formed by the nitrogen vacancy (VN) in the unit cell of g-C3N4 and a small widening of visible light absorption. This nitrogen-based photocatalyst with nitrogen deficiencies was found to deliver an average hydrogen generation rate of 1.16 mmolg-1h-1 at room temperature (25 oC), which was 3.4 times greater than pristine g-C3N4. This process of introducing nitrogen defects into the graphitic carbon provides a promising way for enhancing the photocatalytic activity of g-C3N4-based materials for hydrogen production.
关键词： nitrogen vacancies,photocatalytic hydrogen production,g-C3N4,bandgap
更新于2025-09-23 15:22:29
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Facile two-step synthesis of porous carbon nitride with enhanced photocatalytic activity using a soft template
摘要： In this study, we successfully synthesized a thin-slice layer of graphitic carbon nitride (g-C3N4) with abundant irregular holes by a facile two-step way using Pluronic P123 as a template (CN-P123-x, where x represents the mass ratio of melamine to Pluronic P123). The characterization data suggest that the introduction and removal of Pluronic P123 altered the chemical material structure of the carbon nitride. The CN-P123-x presented lamellar structure with irregular holes, whereas H-g-C3N4 (g-C3N4 prepared using a mild hydrothermal and calcination method without Pluronic P123 or HCl) has a dense blocky structure. Additionally, the prepared CN-P123-x exhibited an effective Rhodamine B (RhB) degradation rate of 98.7% within 40 min of illumination. The optimal photocatalytic activity of CN-P123-6 for degrading RhB was 13.9 times greater than that of H-g-C3N4 in terms of the kinetic constant. Furthermore, the H2 evolution rate of CN-P123-6 can reach 1074.9 μmol?g?1?h?1, whereas that of H-g-C3N4 is only 3.1 μmol?g?1?h?1. It is worth noting that the adoption of HCl (H-g-C3N4-HCl) and Pluronic P123 (CN-P123-6 without HCl) alone has no insignificant effect on photocatalytic performance. The intensive activities are on account of the irregular pores in the thin slice, which increase the specific surface area of the sample and provide additional active sites for reaction. This work provides an excellent basis for improving the performance of the photocatalytic degradation and hydrogen production of carbon nitride.
关键词： Rhodamine B (RhB),H-g-C3N4,hydrogen production,photocatalytic degradation,CN-P123-x
更新于2025-09-23 15:22:29
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Photocatalytic Hydrogen Production Under Near-UV Using Pd-Doped Mesoporous TiO2 and Ethanol as Organic Scavenger
摘要： Photocatalysis can be used advantageously for hydrogen production using a light source (near-UV light), a noble metal-doped semiconductor and an organic scavenger (2.0 v/v% ethanol). With this end, palladium was doped on TiO2 photocatalysts at different metal loadings (0.25 to 5.00 wt%). Photocatalysts were synthetized using a sol-gel method enhancing morphological properties with a soft template precursor. Experiments were carried out in the Photo-CREC Water II reactor system developed at CREC-UWO (Chemical Reactor Engineering Centre- The University of Western Ontario) Canada. This novel unit offers hydrogen storage and symmetrical irradiation allowing precise irradiation measurements for macroscopic energy balances. Hydrogen production rates followed in all cases a zero-order reaction, with quantum yields as high as 30.8%.
关键词： Quantum Yield,Photo-CREC Water II reactor,Palladium,Hydrogen production,TiO2
更新于2025-09-23 15:22:29
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Photo-Induced Phase Transition of CdZnS Based Nanocomposite at Room Temperature Under Solar Irradiation
摘要： Photo-induced phase transition (PIPT) of CdZnS based nanocomposites that was performed at the room temperature under the solar light illumination is reported here for the first time. CdZnS particles were decorated on reduced graphene oxide (RGO) with a solvothermal process and consequently RGO-CdZnS-5%Pt nanocomposites (PC) have been synthesized as zinc blende (cubic) phase of CdZnS. Zinc blende structure (cubic) of CdZnS components of PC was turned to wurtzite (hexagonal) crystal structure with PIPT during the photocatalytic hydrogen evolution reaction. The band gap of the photocatalyst decreased from 2.42 to 2.19 eV and the hydrogen evolution rate increased from 37.3 to 184.0 μ mol h?1 due to the PIPT process.
关键词： Photo-induced phase transition,Hydrogen production,Metal chalcogenides,Photocatalyst
更新于2025-09-23 15:22:29
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Bio-inspired Z-scheme g-C3N4/Ag2CrO4 for efficient visible-light photocatalytic hydrogen generation
摘要： Due to low charge separation efficiency and poor stability, it is usually difficult for single-component photocatalysts such as graphitic carbon nitride (g-C3N4) and silver chromate (Ag2CrO4) to fulfill photocatalytic hydrogen production efficiently. Z-scheme charge transport mechanism that mimics the photosynthesis in nature is an effective way to solve the above problems. Inspired by photosynthesis, we report Ag2CrO4 nanoparticles-decorated g-C3N4 nanosheet as an efficient photocatalyst for hydrogen evolution reaction (HER) with methanol as sacrificial agent. The formation of Z-scheme g-C3N4/Ag2CrO4 nanosheets photocatalysts could inhibit the recombination of photogenerated electron-hole pairs, promote the generation of hydrogen by photosplitting of water. The experiment results indicate that g-C3N4/Ag2CrO4 nanocomposites present enhanced photocatalytic activity and stability in the H2 evolution of water splitting. And the nanocomposites g-C3N4/Ag2CrO4(23.1%) show the 14 times HER efficiency compared to that of bare g-C3N4.
关键词： visible-light,Z-scheme,hydrogen production,g-C3N4,Ag2CrO4,photocatalysts
更新于2025-09-23 15:21:21
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Efficient Photocatalytic Activity of MSnO3 (M: Ca, Ba, Sr) Stannates for Photoreduction of 4-Nitrophenol and Hydrogen production under UV light irradiation
摘要： This work reports the photocatalytic activity of MSnO3 (M = Ca, Ba, Sr) stannates for the degradation of the dangerous compound 4-Nitrophenol (4-NP), as well as for hydrogen generation starting from clear water. These stannates were prepared by a co-precipitation method. The photocatalytic degradation experiments under UV irradiation point out that the BaSnO3 stannate produced a total degradation of 4-NP after 3 h and this was due to its higher OH radical’s generation rate. This was confirmed by the high fluorescence signal (at 430 nm) produced after the excitation of the Teraphtalic acid/·OH complex, which was formed in presence of the BaSnO3 compound. The CaSnO3 and SrSnO3 stannates produced degradation percentages of 4-NP in the range of 80-95%. However, these stannates produced an innocuous compound: 4-aminophenol, which is widely used in the pharmaceutical industry. The results also indicated that the SrSnO3 stannate had the highest hydrogen production rate of 160 μmol·g-1·h-1. Scanning electron microscopy (SEM) analysis demonstrated that the stannates are formed of polyhedral nanoparticles with sizes in the range of 50-400 nm. The structural analysis by X-ray diffraction confirmed that the BaSnO3 stannate presents a cubic phase while the SrSnO3 and CaSnO3 stannates have an orthorrombic phase. Due to their good performance for photoreduction and hydrogen production, we consider that the stannates reported here could be candidates for the degradation of contaminants in water effluents or for the generation of a clean source of energy.
关键词： 4-Nitrophenol,Hydrogen production,Photocatalysis,Stannates
更新于2025-09-23 15:21:21