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Enhanced Charge Separation in g-C3N4 – BiOI Heterostructures for Visible Light Driven Photoelectrochemical Water Splitting
摘要： Heterojunctions of the low bandgap semiconductor bismuth oxyiodide (BiOI) with bulk multilayered graphitic carbon nitride (g-C3N4) and few layered graphitic carbon nitride sheets (g-C3N4-S) are synthesized and investigated as an active photoanode material for sunlight driven water splitting. HR-TEM and elemental mapping reveals formation of a unique heterostructure between BiOI platelets and the carbon nitride (g-C3N4 and g-C3N4-S) network that consisted of dendritic BiOI nanoplates surrounded by g-C3N4 sheets. The presence of BiOI in g-C3N4-S/BiOI and g-C3N4-S/BiOI nanocomposites extends the visible light absorption profile from 500 nm up to 650 nm. Due to excellent charge separation in g-C3N4/BiOI and g-C3N4-S/BiOI, evident from quenching of the carbon nitride photoluminescence (PL) and a decrease in the PL lifetime, a significant increase in photoelectrochemical performance is observed for both types of g-C3N4-BiOI heterojunctions. In comparison to heterojunctions of bulk g-C3N4 with BiOI, the nancomposite consisting of few layered sheets of g-C3N4 and BiOI exhibits higher photocurrent density due to lower recombination in few layered sheets. A synergistic trap passivation and charge separation is found to occur in the g-C3N4-S/BiOI nanocomposite heterostructure which results in a higher photocurrent and a lower charge transfer resistance.
关键词： visible light driven photocatalysis,earth abundant semiconductor heterostructures,Graphenic semiconductors,photoelectrochemistry
更新于2025-11-21 11:01:37
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In-situ solid phase thermal transformation of self-assembled melamine phosphotungstates produce efficient visible light photocatalysts
摘要： Visible-light-driven stacked-layer heterogeneous photocatalyst carbonitride/tungstophosphate (TCN) was constructed via in-situ solid-state thermal transformation using melamine phosphotungstate (MPW). The structural, morphological and optical properties of the samples were investigated. Compared to the MPW hybrids and phosphotungstic acid hydrate, the TCN photocatalysts showed excellent visible light photocatalytic activity. During the thermal transformation, the melamine molecules polymerize to form the defective heptazine structure carbonitride attached to the surface of mixed-valence Keggin units. The interfacial POMs anions-p interactions, ligand-to-metal charge transfer and mix-valence organic-POMs structure makes the electrons fully delocalized over the MPW hybrids, and the TCN photocatalysts obtain the extended light absorption. The Keggin units accept and transfer electrons, so the recombination of photogenerated carriers is suppressed. 13TCN-390 obtains the optimal photocatalytic activity, its photocatalytic degradation efficiency of imidacloprid and rate constant k are 6.38 and 13.50 times than that of CN-390, respectively. The enhanced photocatalytic activity arises from the extended light absorption, suppressed photogenerated carriers’ recombination, surface structure defect and suitable band structure. h+ and (cid:1)OH are the main reactive species when the proposed photocatalytic mechanism was done. This study provides a promising construction strategy for polymer/POMs photocatalysts using different organic-POMs hybrids.
关键词： Melamine phosphotungstate,Visible-light-driven photocatalyst,Degradation,Thermal transformation
更新于2025-11-14 17:04:02
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2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterostructure for high photocatalytic activity
摘要： A novel 2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterojunction photocatalyst with modified interfacial microstructure and electronic properties was synthesized by ultrasonic-assisted calcination method. The remarkably active g-C3N4 could provide high productivity of photogenerated electrons and holes. Meanwhile, the O/OH-terminated Ti3C2 and by-product TiO2 could act as excellent supporters by migrating electrons in TiO2@Ti3C2/g-C3N4 hybrids. As a result, the highest photocatalytic activities in the degradation of aniline and RhB were increased to 5 and 1.33 times higher than that of pristine g-C3N4 under visible-light irradiation, respectively. Furthermore, we proposed that n–n heterojunction and n-type Schottky heterojunction were built up across their interfaces, which efficiently improve the transition of electrons and further promote the photocatalytic activity of TiO2@Ti3C2/g-C3N4 hybrids. More appealingly, all the results highlight that the environment-friendly TiO2@Ti3C2/g-C3N4 heterojunction hybrids would be desirable candidates for pollutants degradation.
关键词： 2D materials,photocatalytic activity,TiO2@Ti3C2/g-C3N4,ternary heterojunction,pollutants degradation,visible-light-driven
更新于2025-11-14 17:03:37
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Efficient photocatalytic debromination of 2,2?,4,4?-tetrabromodiphenyl ether by Ag-loaded CdS particles under visible light
摘要： Highly active and visible light-driven Ag-loaded CdS photocatalysts were prepared via a hydrothermal synthesis and photodeposition method. The removal and debromination of 2,2?,4,4?-tetrabromodiphenyl ether was achieved efficiently using this Ag-loaded CdS under visible light, with a removal efficiency of 100% and a debromination ratio of 44.3% being achieved within 30 min. Both the reaction solvent and the water content were found to have a strong influence on the removal efficiency and the debromination ratio. In addition, the stepwise debromination preference was ortho > para, thereby indicating that the main debromination pathway was electron reduction. The stability and efficiency of these Ag-loaded CdS photocatalysts for the removal of BDE47 were satisfactory, and so our results confirmed the development of a promising visible light-driven catalyst for the removal of polybrominated diphenyl ethers.
关键词： Debromination ratio,Visible light-driven,Ag-loaded CdS,Photocatalyst,Removal efficiency
更新于2025-09-23 15:23:52
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High efficient catalytic degradation of tetracycline and ibuprofen using visible light driven novel Cu/Bi2Ti2O7/rGO nanocomposite: Kinetics, intermediates and mechanism
摘要： The photoexcited charge carriers trapping was an effective way to generate a large number of active species like O2?? and ?OH radicals to oxidize pharmaceutical molecules. In ternary Cu/Bi2Ti2O7/rGO composite Cu nanoparticles and rGO sheets act as charge carrier trappers and the suppression of e--h+ pair recombination was confirmed by Photoluminescence analysis. The Cu/Bi2Ti2O7/rGO composite exhibited higher photocatalytic degradation efficiency for degradation of ibuprofen and tetracycline molecules under visible light irradiation within 90 min. Therefore, this research designates a promising strategy for higher photoexcited charge carrier trapping photocatalyst design for efficient degradation of pharmaceutical molecules.
关键词： Nanocomposite,Visible light-driven,Hydrothermal,Pharmaceutical contamination.,Charge carrier trappers
更新于2025-09-23 15:23:52
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Nanocrystal-engineered thin CuO film photocatalyst for visible-light-driven photocatalytic degradation of organic pollutant in aqueous solution
摘要： We design a thin CuO film photocatalyst for visible-light-driven photocatalytic degradation of methylene blue (MB). Nanocrystal engineering of the photocatalyst is performed by sputtering with concurrent in-situ thermal treatment. The impacts of the in-situ thermal treatment temperature and sputtering conditions on the material properties of the thin CuO film photocatalyst are investigated in detail. Systematic characterization using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) indicates that deposition at elevated temperature and higher sputtering power significantly improves the surface structure and crystallinity of thin CuO film, which promotes charge transfer and ultimately results in better performance for MB photocatalytic degradation. The best-performing sample is the one sputtered at an elevated temperature of 300 °C and a sputtering power of 300 W. The photodegradation efficiency and physical durability of the samples were also analyzed after using for 5 cycles. The results indicate that in-situ thermal treatment and nanocrystal engineering of the thin CuO film significantly improve the physical durability.
关键词： Thin CuO film photocatalyst,Visible-light-driven photocatalytic degradation,Nanocrystal engineering
更新于2025-09-23 15:23:52
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Construction of Strontium Titanate/Binary Metal Sulfide Heterojunction Photocatalysts for Enhanced Visible-Light-Driven Photocatalytic Activity
摘要： A novel strontium titanate/binary metal sulfide (SrTiO3/SnCoS4) heterostructure was synthesized by a simple two-step hydrothermal method. The visible-light-driven photocatalytic performance of SrTiO3/SnCoS4 composites was evaluated in the degradation of methyl orange (MO) under visible light irradiation. The photocatalytic performance of SrTiO3/SnCoS4-5% is much higher than that of pure SrTiO3, SnCoS4, SrTiO3/SnS2 and SrTiO3/CoS2. The SrTiO3/SnCoS4 composite material with 5 wt.% of SnCoS4 showed the highest photocatalytic efficiency for MO degradation, and the degradation rate could reach 95% after 140 min irradiation time. The enhanced photocatalytic activity was ascribed to not only the improvement of visible light absorption efficiency, but also the construction of a heterostructure which make it possible to effectively separate photoexcited electrons and holes in the two-phase interface.
关键词： visible-light-driven,SnCoS4,heterojunction,degradation,SrTiO3
更新于2025-09-23 15:23:52
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Sustainable Recovery of CO2 by Using Visible-Light-Responsive Crystal Cuprous Oxide/Reduced Graphene Oxide
摘要： A simple solution-chemistry method has been investigated to prepare crystal cuprous oxide (Cu2O) incorporated with reduced graphene oxide (designated as Cu2O-rGO-x, where x represents the contents of rGO = 1%, 5% and 10%) in this work. These Cu2O-rGO-x composites combine the prospective advantages of rhombic dodecahedra Cu2O together with rGO nanosheets which have been studied as visible-light-sensitive catalysts for the photocatalytic production of methanol from CO2. Among the Cu2O-rGO-x photocatalysts, the methanol yield photocatalyzed by Cu2O-rGO-5% can be observed to be 355.26 μmol g?1cat, which is ca. 36 times higher than that of pristine Cu2O nanocrystal in the 20th hour under visible light irradiation. The improved activity may be attributed to the enhanced absorption ability of visible light, the superior separation of electron–hole pairs, well-dispersed Cu2O nanocrystals and the increased photostability of Cu2O, which are evidenced by employing UV-vis diffuse reflection spectroscopy, photoluminescence, scanning electron microscopy/transmission electron microscopy and X-ray photoelectron spectroscopy, respectively. This work demonstrates an easy and cost-effective route to prepare non-noble photocatalysts for efficient CO2 recovery in artificial photosynthesis.
关键词： cuprous oxide,solar energy,visible-light-driven,graphene,CO2 conversion
更新于2025-09-23 15:22:29
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Design of an inherently-stable water oxidation catalyst
摘要： While molecular water-oxidation catalysts are remarkably rapid, oxidative and hydrolytic processes in water can convert their active transition metals to colloidal metal oxides or hydroxides that, while quite reactive, are insoluble or susceptible to precipitation. In response, we propose using oxidatively-inert ligands to harness the metal oxides themselves. This approach is demonstrated by covalently attaching entirely inorganic oxo-donor ligands (polyoxometalates) to 3-nm hematite cores, giving soluble anionic structures, highly resistant to aggregation, yet thermodynamically stable to oxidation and hydrolysis. Using orthoperiodate (at pH 8), and no added photosensitizers, the hematite-core complex catalyzes visible-light driven water oxidation for seven days (7600 turnovers) with no decrease in activity, far exceeding the documented lifetimes of molecular catalysts under turnover conditions in water. As such, a fundamental limitation of molecular complexes is entirely bypassed by using coordination chemistry to harness a transition-metal oxide as the reactive center of an inherently stable, homogeneous water-oxidation catalyst.
关键词： visible-light driven,hematite,polyoxometalates,water oxidation,catalyst
更新于2025-09-23 15:21:01
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An efficient and robust exfoliated bentonite/Ag <sub/>3</sub> PO <sub/>4</sub> /AgBr plasmonic photocatalyst for degradation of parabens
摘要： Efficient visible-light-driven heterojunction photocatalysts have attracted broad interest owing to their promising adsorption and degradation performances in the removal of organic pollutants. In this study, a mesoporous exfoliated bentonite (EB)/Ag3PO4/AgBr (30%) photocatalyst was obtained by stripping and exfoliating bentonite as the support for loading Ag3PO4 and AgBr. The particle size ranges of Ag3PO4 and AgBr were about 10–30 nm and 5–10 nm, respectively. The exfoliated bentonite could greatly improve the dispersion and adsorption of Ag3PO4 and AgBr, and significantly enhance the stability of the material during paraben photodegradation. 0.2 g L?1 methylparaben (MPB) was completely decomposed over the EB/Ag3PO4/AgBr (30%) in 40 min under visible light irradiation. In addition, the photocatalytic activity of EB/Ag3PO4/AgBr (30%) remained at about 91% after five recycling runs manifesting that EB/Ag3PO4/AgBr (30%) possessed excellent stability. Radical quenching tests revealed that holes (h+) and hydroxyl radicals (?OH) were the major radicals. They attacked the side chain on the benzene ring of parabens, which were gradually oxidized to the intermediates, such as benzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, azelaic acid, and eventually became CO2 and H2O. The enhancement of photocatalytic activity and photo-stability could be ascribed to the stable structural characteristics, enlarged surface area, high absorption ability, and improved light absorption ability from loading Ag3PO4 onto EB. Meanwhile, the matched energy levels of Ag3PO4 and AgBr made the photoelectron–hole pairs separate and transfer effectively at the interfaces. As a result, the photocatalytic properties of EB/Ag3PO4/AgBr (30%) composites were enhanced.
关键词： heterojunction photocatalysts,exfoliated bentonite,Ag3PO4/AgBr,paraben photodegradation,visible-light-driven
更新于2025-09-23 15:19:57