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Self-assembled CdS@BN core-shell photocatalysts for efficient visible-light-driven photocatalytic hydrogen evolution
摘要： CdS@BN NRs core-shell photocatalysts for hydrogen evolution were synthesized by a solvothermal and chemical adsorption method. CdS NRs coated by 5 wt% boron nitride (BN) shell exhibited remarkably visible-light photocatalytic hydrogen evolution activity of up to 30.68 mmol g?1 h?1, nearly 6.79 times higher than that of pure CdS NRs, and the apparent quantum efficiency at 420 nm was 7.5%. Transmission electron microscopy showed the CdS NRs were coated with a thin (~5 nm) BN layer, which together with the hydrogen evolution results proved the photocatalytic ability of CdS NRs was significantly improved. The hydrogen evolution rate of CdS NRs coated by 5 wt% BN remained at 91.4% after four cycles, indicating the photocorrosion of CdS NRs was effectively alleviated. Moreover, the large and close coaxial interfacial contact between the CdS core and the BN shell was beneficial to the separation and transfer of photogenerated electron-hole pairs.
关键词： Core-shell structure,Photocatalytic hydrogen evolution,CdS Nanorods,Boron nitride
更新于2025-09-23 15:21:01
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On the processes of photo-induced hydrogen generation from methanol solution by Ta3N5 and?WO3
摘要： The hydrogen production rates from deionized water and 20% methanol solution, with or without the presence of Ta3N5, WO3, and the indirect Z-scheme Ta3N5/WO3, were investigated. Under irradiation of a 300 W Xe lamp, all of these three catalysts assisted hydrogen generation in deionized water. In the methanol solution, Ta3N5, and WO3 reduced the hydrogen generation, but Ta3N5/WO3 signi?cantly enhanced the hydrogen production rate by seven times. Under visible light irradiation, the effects of the three catalysts are different from those under full spectrum irradiation. The mechanisms based on the competition of methanol decomposition and water reduction in the presence of catalyst under different irradiation conditions are proposed to explain the different hydrogen generation behaviors.
关键词： WO3,Sacri?cial reagent,Photocatalytic hydrogen evolution,Methanol,Ta3N5
更新于2025-09-23 15:21:01
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Strongly coupled 2D-2D nanojunctions between P-doped Ni2S (Ni2SP) cocatalysts and CdS nanosheets for efficient photocatalytic H2 evolution
摘要： Developing low-cost, environment-friendly and highly-active nanocomposites for photocatalytic hydrogen evolution reaction (HER) holds pivotal function in water splitting. Supported cocatalysts on semiconductor can facilitate speedy transfer and separation of photoexcited charge, active interfacial response and suppress photocorrosion. We, for the first time, proposed a novel strategy to formed 2D-2D (two dimensional) nanocomposites by loading 2D P-doped Ni2S (Ni2SP) cocatalysts onto 2D CdS nanosheets (NSs). The as-obtained 2D-2D CdS/Ni2SP nanocomposites exhibited excellent HER activity in 0.25 M Na2S-Na2SO3 sacrificial solution under visible light (λ ≥ 420 nm). The optimal loading of 2 wt% 2D Ni2SP on 2D CdS as a cocatalyst yielded an optimal H2 production rate at 18.96 mmol g-1 h-1, which was approximately 3.26 folds higher than that of bare 2D CdS (5.82 mmol g-1 h-1) without cocatalysts. In the presence of non-precious metal, the highest apparent quantum efficiency of 4.8% was recorded at 420 nm. The enhanced photocatalytic HER activity was attributed to the excellent interfacial coupling effects of Ni2SP NSs cocatalyst with CdS NSs, which was essential for the rapid charge separation and transfer, increased number of active sites and improved H2-evolution kinetics. This study offers a feasible scheme to design efficient photocatalysts system to produce hydrogen.
关键词： Charge separation and transfer,2D-2D nanojunctions,P-doped Ni2S (Ni2SP) cocatalysts,Photocatalytic hydrogen evolution reaction
更新于2025-09-23 15:19:57
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Enhanced photocatalytic hydrogen evolution of?CdWO4 through polar organic molecule modification
摘要： In this work, a polar molecule 4-mercaptobenzoic acid (4-MBA) is anchored on the surface of CdWO4 by forming CdeS and WeS bond. Photocatalytic hydrogen evolution is significantly enhanced (about 3.41 times) after the modification. The reason is due to the modification of 4-MBA, which results in a polar surface and built-in electric field. The polar surface is confirmed by the steady state and time-resolved PL spectra, Voc and SHG results.
关键词： CdWO4,Photocatalytic hydrogen evolution,4-mercaptobenzoic acid,Surface modification,Built-in electric field
更新于2025-09-19 17:15:36
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Synthesis and Characterization of a Rare Transition-Metal Oxothiostannate and Investigation of Its Photocatalytic Properties
摘要： The new transition-metal oxothiostannate [Ni(cyclen)(H2O)2]4[Sn10S20O4]·～13H2O (1) was prepared under hydrothermal conditions using Na4SnS4·14H2O as the precursor in the presence of [Ni(cyclen)(H2O)2](ClO4)2·H2O. Compound 1 comprises the [Sn10S20O4]8? anion constructed by the T3-type supertetrahedron [Sn10S20] and the [Sn10O4] anti-T2 cluster. Channels host the H2O molecules, and the sample can be reversibly dehydrated and rehydrated without significantly affecting the crystallinity of the material. 119Sn NMR spectroscopy of an aqueous solution of Na4SnS4·14H2O evidences that between 25 and 120 °C only [SnS4]4? and [Sn2S6]4? anions are present. In further experiments, hints were found that the formation of the tin oxosulfide ions depends on the Ni2+-centered complexes. Compound 1 exhibits promising photocatalytic properties for the visible-light-driven hydrogen evolution reaction, with 18.7 mmol·g?1 H2 being evolved after 3 h.
关键词： photocatalytic hydrogen evolution,oxothiostannate,NMR spectroscopy,hydrothermal synthesis,transition-metal complex
更新于2025-09-19 17:15:36
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Self-Assembled Amphiphilic Molecules for Highly Efficient Photocatalytic Hydrogen Evolution From Water
摘要： Self-assembled molecules for outstanding hydrogen evolution rate and durability should promise practical water splitting due to the versatile visible light absorption, low production cost and ease of control. Here, we adapted an amphiphilic molecule as a building block for efficient small molecule based self-assembled photocatalyst for hydrogen evolution from water. The self-assembled molecules with platinum co-catalyst showed outstanding performance (turnover number ~ 27,000) virtually comparable to the state-of-the-art metal oxide based photocatalysts with catalytic activity extending over days. Transient absorption studies in combination with quantum chemical calculations revealed that elaborate excited state engineering of the molecules resulted in such high performance of hydrogen evolution from water. This study shows that the self-assembled amphiphilic molecules could pave the way to more economical and reproducible production of hydrogen from water.
关键词： Platinum co-catalyst,Amphiphilic molecule,Photocatalytic hydrogen evolution,Excited state engineering,Self-assembled molecules
更新于2025-09-19 17:13:59
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A nanoreactor based on SrTiO3 coupled TiO2 nanotubes confined Au nanoparticles for photocatalytic hydrogen evolution
摘要： A TiO2 nanotube-based nanoreactor was designed and fabricated by facile two steps synthesis: firstly, hydrothermal synthesized SrTiO3 was deposited on TiO2 nanotubes (TiO2NTs). Secondly, the Au nanoparticles (NPs) were encapsulated inside the TiO2NTs followed by vacuum-assisted impregnation. The as-synthesized composites were characterized using Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Photoluminescence spectra (PL) and Ultravioletevisible absorption spectroscopy (UVevis). The photocatalytic performance was evaluated by the hydrogen evolution reaction. The results revealed that the SrTiO3 modified TiO2NTs confined Au NPs (STO-TiO2NTs@Au) achieved an enhanced hydrogen evolution rate at 7200 mmol h?1 g?1, which was 2.2 times higher than that of bald TiO2NTs@Au at 3300 mmol h?1 g?1. The improved photocatalytic activity could be attributed to the synergistic effect of the electron-donating of SrTiO3 and TiO2NTs confinement. The as-designed nanoreactor structure provides an example of efficient carriers’ separation photocatalyst.
关键词： Au nanoparticles,Confinement,SrTiO3,TiO2 nanotubes,Photocatalytic hydrogen evolution
更新于2025-09-12 10:27:22
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Type-II heterostructures of <b>α</b> -V <sub/>2</sub> O <sub/>5</sub> nanowires interfaced with cadmium chalcogenide quantum dots: Programmable energetic offsets, ultrafast charge transfer, and photocatalytic hydrogen evolution
摘要： We synthesized a new class of heterostructures by depositing CdS, CdSe, or CdTe quantum dots (QDs) onto α-V2O5 nanowires (NWs) via either successive ionic layer adsorption and reaction (SILAR) or linker-assisted assembly (LAA). SILAR yielded the highest loadings of QDs per NW, whereas LAA enabled better control over the size and properties of QDs. Soft and hard x-ray photoelectron spectroscopy in conjunction with density functional theory calculations revealed that all α-V2O5/QD heterostructures exhibited Type-II band offset energetics, with a staggered gap where the conduction- and valence-band edges of α-V2O5 NWs lie at lower energies (relative to the vacuum level) than their QD counterparts. Transient absorption spectroscopy measurements revealed that the Type-II energetic offsets promoted the ultrafast (10?12–10?11 s) separation of photogenerated electrons and holes across the NW/QD interface to yield long-lived (10?6 s) charge-separated states. Charge-transfer dynamics and charge-recombination time scales varied subtly with the composition of heterostructures and the nature of the NW/QD interface, with both charge separation and recombination occurring more rapidly within SILAR-derived heterostructures. LAA-derived α-V2O5/CdSe heterostructures promoted the photocatalytic reduction of aqueous protons to H2 with a 20-fold or greater enhancement relative to isolated colloidal CdSe QDs or dispersed α-V2O5 NWs. The separation of photoexcited electrons and holes across the NW/QD interface could thus be exploited in redox photocatalysis. In light of their programmable compositions and properties and their Type-II energetics that drive ultrafast charge separation, the α-V2O5/QD heterostructures are a promising new class of photocatalyst architectures ripe for continued exploration.
关键词： α-V2O5 nanowires,cadmium chalcogenide quantum dots,photocatalytic hydrogen evolution,programmable energetic offsets,Type-II heterostructures,ultrafast charge transfer
更新于2025-09-12 10:27:22
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Enhanced photocatalytic hydrogen evolution over TiO2/g-C3N4 2D heterojunction coupled with plasmon Ag nanoparticles
摘要： 2D heterojunction based on g-C3N4 nanosheets with other semiconductor nanosheets is a promising way to improve photocatalytic hydrogen evolution (PHE) activity over g-C3N4. However, current 2D heterojunction based on g-C3N4 are unsatisfactory due to their insu?cient absorption of visible light and ine?cient charge separation. In this work, Ag/TiO2/g-C3N4 nanocomposites based on 2D heterojunction coupling with Ag surface plasmon resonance (SPR) were synthesized by a method combining facile wetness impregnation calcination. The PHE activity of Ag/TiO2/g-C3N4 nanocomposites is attributed to the TiO2/g-C3N4 2D heterojunction and bare g-C3N4 nanosheet under visible light irradiation, indicating a cooperative e?ect between Ag and TiO2/g-C3N4 2D heterojunction. As a result of SPR e?ect, the composites strongly absorb visible light. In addition, the oscillating hot electrons from Ag can easily transfer to 2D heterojunction. This synergistic e?ect lead to su?cient visible light absorption and e?cient charge separation of 2D heterojunction, which improved the PHE activity of g-C3N4. This work indicates that loading metal nanoparticles on 2D heterojunction as metal SPR-2D heterojunction nanocomposites may be a potential method for harvesting visible light for PHE.
关键词： Surface plasmon resonance,Photocatalytic hydrogen evolution,TiO2,2D heterojunction,g-C3N4
更新于2025-09-12 10:27:22
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Self-constructed facet junctions on hexagonal CdS single crystals with high photoactivity and photostability for water splitting
摘要： Crystal facets engineering of semiconductor catalysts with different exposed facets has been proven as a versatile approach to enhance their photocatalytic performance. Herein, for the first time, a facet-junction engineered hexagonal CdS single crystal with exposing {0001} and {10 0} facets was synthesized by hydrothermal reaction via adjusting the molar ratio of S2-/Cd2+ precursor. The co-exposed {0001} and {10 0} facets on hexagonal CdS single crystals with continuous band bending and well-defined epitaxial interfaces showed highly efficient visible-light-induced H2 evolution. The maximum photocatalytic H2 production rate of 24.33 mmol h?1g?1 is obtained over the facet-junction engineered hexagonal CdS-5 single crystals with an apparent quantum efficiency of 11.18% at 470 nm, which is about 5.27 times greater than CdS-1 nanoparticles. Also, superior photostability is also achieved, even after 25 consecutive cycles during 100 h light irradiation keeping impregnated in strong alkaline sacrificial agent beyond 20 days, the initial photoactivity is still remained. The enhanced photocatalytic H2 evolution activity and photostability can be ascribed to the type-II band alignment between the co-exposed {0001} and {10 0} facets that significantly promoted the separation rate of photo-generated electrons and holes. And the small amount of sulfur vacancies are also benefit for the photocatalytic hydrogen evolution activity of CdS-5. The time-resolved fluorescence (TRPL) decay and photoelectrochemical test further proved the effective spatial charge separation. This work provides a feasible and simple strategy for designing of facet-junction engineered CdS single crystals with highly efficient photocatalytic activity and unprecedented photostability.
关键词： hexagonal CdS single crystals,{0001} facets,photocatalytic hydrogen evolution,facet junction
更新于2025-09-10 09:29:36