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Strengthened spatial charge separation over Z-scheme heterojunction photocatalyst for efficient photocatalytic H2 evolution
摘要： Graphitic carbon nitride (g-C3N4) is a very promising earth abundant and visible light response photocatalyst for H2 production. Fabricating novel nanostructure or combining with other semiconductors have been attempted to further enhance its activity. α-FeOOH, due to its structures greatly facilitating electrolyte transport, has been widely used as an excellent OER cocatalyst assisting the PEC water splitting process. However, to the best of our knowledge, it has not been attempted in photocatalytic H2 generation. Herein, g-C3N4 modi?ed with β-FeOOH was designed for the ?rst time for photocatalytic H2 production. It showed H2 production rate as 2.02 mmol·h?1·g?1, which was almost 6 times of pure g-C3N4. The signi?cantly promoted catalytic activity was ascribed to the greatly enhanced charge separation e?ciency by forming spatial separated reservoirs of photo activated electrons and holes in the Z-scheme heterojunction, corresponding to the conduction band of g-C3N4 and the valence band of β-FeOOH, respectively. Our work should be valuable for fabricating visible-light response heterojunction based photocatalysts with better photocatalytic performance.
关键词： Hydrogen evolution,β-FeOOH,Graphitic carbon nitride,Photocatalysis,Heterojunction
更新于2025-09-23 15:22:29
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ZnO/CdS/PbS nanotube arrays with multi-heterojunctions for efficient visible-light-driven photoelectrochemical hydrogen evolution
摘要： High performance, low cost and sustainable photocatalytic evolution of hydrogen is a promising energy supply alternative for modern society to resolve the depletion crisis of fossil fuel. The design of multi-heterojunction visible-light photocatalysts combined with electrochemical means is considered one of the most attractive options in recent years. In this work, a photoanode composed of top-opened ZnO/CdS/PbS nanotube arrays (ZnO/CdS/PbS ONTs) with multi-heterojunctions was synthesized via a three-step process, i.e. hydrothermal treatment, chemical bath deposition and successive ionic layer adsorption reaction (SILAR). This as-prepared photoanode exhibited remarkable photoelectrochemical activity under visible light irradiation. The photocurrent density and photoelectrochemical hydrogen evolution efficiency of the optimized ZnO/CdS/PbS ONTs reached up to 14.2 mA cm-2 and 5.5 mL cm-2 h-1 at 0.0 V vs. Ag/AgCl, respectively. The efficiency was 3.1 times that of top-closed ZnO/CdS nanotubes (1.8 mL cm-2 h-1). The experimental results suggest that the high photoelectrochemical activity can be ascribed to the inherent advantages of the structural and successive energy level relays design: on the one hand, the top-opened nanotube structure significantly enlarges surface area of the nanostructure, which facilitates efficient light absorption and rapid mass transport; on the other hand, the well-matched band energy edge of the multi-heterojunction interfaces literally build efficient electron highways to deliver electrons to reaction sites and reduce the recombination of photogenerated charge carriers.
关键词： CdS,visible light,multi-heterojunction,ZnO,photoelectrochemical hydrogen evolution,PbS
更新于2025-09-23 15:22:29
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One-step synthesis of hierarchical AuNPs/Cd0.5Zn0.5S nanoarchitectures and their application as an efficient photocatalyst for hydrogen production
摘要： The hierarchical AuNPs/Cd0.5Zn0.5S hybrids are directly fabricated via a facile one-step in-situ hydrothermal method. The as-prepared AuNPs/Cd0.5Zn0.5S hybrids demonstrate superior photocatalytic performance toward hydrogen production under visible light irradiation. The hydrogen evolution rate of the 5 wt% AuNPs/Cd0.5Zn0.5S synthesized with in-situ hydrothermal method can be 7.1 times greater than that of pure Cd0.5Zn0.5S and as much as 2.5 times of 5 wt% AuNPs loaded Cd0.5Zn0.5S synthesized with photodeposition method. Systematical investigations reveal that the enhanced photocatalytic performance of the one-step in-situ prepared AuNPs/Zn0.5Cd0.5S can be attributed to the inherent SPR effect and favorable electron transfer properties of AuNPs, as well as the rational hierarchical nanoarchitectures that allow AuNPs to be uniformly incorporated into Zn0.5Cd0.5S matrix. This one-step in-situ fabrication method provides a simple and efficient route to synthesize well-defined heterocatalysts.
关键词： AuNPs/Cd0.5Zn0.5S,Photocatalysis,Hydrogen evolution,SPR,One-step
更新于2025-09-23 15:22:29
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Organic-inorganic hybrid perovskite – TiO2 nanorod arrays for efficient and stable photoelectrochemical hydrogen evolution from HI splitting
摘要： Solar-driven photoelectrochemical (PEC) hydrogen production offers a promising solution to simultaneously tackle the global energy crisis and the environmental pollution. Herein, we report a PEC cell of organic-inorganic hybrid perovskite (methylammonium lead iodide, MAPbI3)-TiO2 nanorod array (TNAs) for efficient and stable hydrogen evolution in aqueous hydrogen iodide (HI) solution. The built-in electric field created across the MAPbI3-TiO2 junction is able to efficiently separate the electron-hole pairs photogenerated in MAPbI3 with electrons quickly injected from MAPbI3 to TiO2, which are then transported along the one-dimensional TiO2 nanorod channels to the counter electrode to reduce proton to evolve hydrogen. The optimized MAPbI3-TNA PEC cell exhibits a high photocurrent density of 1.75 mA cm-2 at 0.14 V (vs. Ag/AgCl) under AM 1.5G illumination, which is able to stably produce molecular hydrogen at a rate of 33.3 mmol cm-2 h-1 for more than 8 h.
关键词： Perovskite,Nanorod arrays,Hydrogen evolution,Heterojunction,Photoelectrochemical
更新于2025-09-23 15:22:29
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Nanostructuring Strategies To Increase the Photoelectrochemical Water Splitting Activity of Silicon Photocathodes
摘要： Photoelectrochemical water splitting is a promising route for sustainable hydrogen production. Herein, we demonstrate a photoelectrode motif that enables a nanostructured large-surface area electrocatalyst without requiring a nanostructured semiconductor surface with the goal of promoting electrocatalysis while minimizing surface recombination. We compare the photoelectrochemical H2 evolution activity of two silicon photocathode nanostructuring strategies: (1) direct nanostructuring of the silicon surface and (2) incorporation of nanostructured zinc oxide to increase the electrocatalyst surface area on planar silicon. We observed that silicon photocathodes that utilized nanostructured ZnO supports outperformed nanostructured silicon electrodes by ～50 mV at open circuit under 1 sun illumination and demonstrated comparable electrocatalytic activity.
关键词： photocathodes,silicon nanowires,hydrogen evolution,molybdenum disulfide,zinc oxide nanowires,photoelectrochemical water splitting
更新于2025-09-23 15:22:29
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Electronic structure and hydrogen evolution reaction in layered ReS<sub>2</sub> regulated by alkali-metal atom intercalation
摘要： Recently, the atom intercalation method has been developed and applied into two-dimensional (2D) materials to regulate their pristine physical property. However, as an important application in hydrogen evolution reaction (HER), the influence of alkali-metal-intercalated technology upon 2D material's electronic structure and catalytic activity should be investigated systematically. In this work, layered ReS2 crystals with a charge decoupling are chosen as a model to explore changes in electronic structure and Gibbs free energies induced by alkali-metal intercalated compounds and external strain. The calculated results disclose that the structural transformation induced by intercalated alkali atom and external strain not only leads to decrease in band gap of ReS2 but also make Gibbs free energy of adsorbed hydrogen close to zero. Our calculations provide an insight to improve HER performance by a simple alkali-metal-intercalated technology.
关键词： hydrogen evolution reaction,electronic structure,alkali-metal-intercalated technology
更新于2025-09-23 15:22:29
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Exfoliated Molybdenum Disulfide Encapsulated in a Metal Organic Framework for Enhanced Photocatalytic Hydrogen Evolution
摘要： An exfoliated MoS2 encapsulated into metal-organic frameworks (MOFs) was fabricated as a promising noble-metal-free photocatalyst for hydrogen production under visible light irradiation. The as-synthesized samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) surface analysis. It is well known that bulk MoS2 is unsuitable for photocatalysis due to its inadequate reduction and oxidation capabilities. However, exfoliated MoS2 exhibits a direct band gap of 2.8 eV due to quantum confinement, which enables it to possess suitable band positions and retain a good visible-light absorption ability. As a result, it is considered to be an encouraging candidate for photocatalytic applications. Encapsulating exfoliated MoS2 into MOF demonstrates an improved visible light absorption ability compared to pure MOF, and the highest hydrogen production rate that the encapsulated exfoliated MoS2 could reach was 68.4 μmol h-1g-1, which was much higher than that of pure MOF. With a suitable band structure and improved light-harvesting ability, exfoliated MoS2@MOF could be a potential photocatalyst for hydrogen production.
关键词： hydrogen evolution,ZIF-8,exfoliation,MOF,MoS2,photocatalyst
更新于2025-09-23 15:22:29
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Enhanced light harvesting and electron-hole separation for efficient photocatalytic hydrogen evolution over Cu7S4-enwrapped Cu2O nanocubes
摘要： P-type Cu2O is an advantageous photocatalyst as the appropriate bandgap structure and low-cost. However, poor photocatalytic and instability of such promising material is still a great challenge. Here the core-shell Cu7S4-coated Cu2O nanocubes (Cu2O/Cu7S4 NCs) were successfully synthesized by solution method coupled with anion exchange, integrated structure of Cu2O/Cu7S4 NCs exhibited apparent improved photocatalytic hydrogen evolution activity compared with Cu2O photocatalyst. Particularly, Cu2O/Cu7S4 NCs had a high hydrogen production rate of 1689.00 μmol·g-1·h-1 under full spectra irradiation with additives of Na2SO3, which was higher than that of Cu2O NCs with a factor of 1.71 times. Excellent synergistic effect of Cu2O and Cu7S4 can be responsible for the improved hydrogen evolution properties, namely, the presence of Cu7S4 with localized surface plasma resonance (LSPR) can promote the photogenerated electrons transfer from the Cu2O surface, prolong the photogenerated holes lifetime, accelerate the separation of photogenerated electrons and holes, and ameliorate the photoelectric properties of semiconductors. The in situ formed multifunctional Cu7S4 layer offers a promising avenue to design photocathodes rationally for photocatalytic water reduction.
关键词： Photocatalyst,Localized surface plasma resonance,Electron-hole separation,Hydrogen evolution reaction,Cu2O/Cu7S4 nanocubes
更新于2025-09-23 15:22:29
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Unique 1D Cd <sub/>1?</sub><i> <sub/>x</sub></i> Zn <i> <sub/>x</sub></i> S@O-MoS <sub/>2</sub> /NiO <i> <sub/>x</sub></i> Nanohybrids: Highly Efficient Visible-Light-Driven Photocatalytic Hydrogen Evolution via Integrated Structural Regulation
摘要： Development of noble-metal-free photocatalysts for highly efficient sunlight-driven water splitting is of great interest. Nevertheless, for the photocatalytic H2 evolution reaction (HER), the integrated regulation study on morphology, electronic band structures, and surface active sites of catalyst is still minimal up to now. Herein, well-defined 1D Cd1?xZnxS@O-MoS2/NiOx hybrid nanostructures with enhanced activity and stability for photocatalytic HER are prepared. Interestingly, the band alignments, exposure of active sites, and interfacial charge separation of Cd1?xZnxS@O-MoS2/NiOx are optimized by tuning the Zn-doping content as well as the growth of defect-rich O-MoS2 layer and NiOx nanoparticles, which endow the hybrids with excellent HER performances. Specifically, the visible-light-driven (>420 nm) HER activity of Cd1?xZnxS@O-MoS2/NiOx with 15% Zn-doping and 0.2 wt% O-MoS2 (CZ0.15S-0.2M-NiOx) in lactic acid solution (66.08 mmol h?1 g?1) is about 25 times that of Pt loaded CZ0.15S, which is further increased to 223.17 mmol h?1 g?1 when using Na2S/Na2SO3 as the sacrificial agent. Meanwhile, in Na2S/Na2SO3 solution, the CZ0.15S-0.2M-NiOx sample demonstrates an apparent quantum yield of 64.1% at 420 nm and a good stability for HER under long-time illumination. The results presented in this work can be valuable inspirations for the exploitation of advanced materials for energy-related applications.
关键词： charge separation,1D hybrid nanostructures,photocatalytic hydrogen evolution,band alignments,active sites
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Hydrogen Evolution with TiO <sub/>2</sub> -TiN Nanoparticle Composites
摘要： Metal nitrides have potential in energy applications due to their physical and optical properties. Nanoparticle composites of titanium nitride (TiN) and titanium dioxide (TiO2) were investigated for their photocatalytic hydrogen (H2) activity via methanol reformation. Physical mixing of the nanoparticulate TiO2 and TiN was employed to prevent the oxy-nitride formation and particle aggregation observed in thermal preparations. This convenient combination of TiO2 and TiN demonstrated a substantial synergistic effect with enhanced activity (9.4 μmol/h TiO2-TiN vs 1.8 μmol/h TiO2) under combined UV/Vis light. Irradiation under only UV light resulted in a similar enhancement factor compared to using combined UV/Vis light, demonstrating that the enhanced activity of the composites occurs essentially for UV-driven photocatalysis. No activity/enhancement was observed with only visible light irradiation, however, minor enhancement was observed when switching between UV and UV/Vis irradiation, suggesting a contribution from the TiN plasmon. We propose that the plasmonic contribution is dependent on the band gap excitation of TiO2, which reduces the degree of band bending at the TiO2/TiN interface. This promotes the migration of hot electrons from TiN away from the TiO2/TiN interface to be used for H2 evolution.
关键词： TiO2-TiN Nanoparticle Composites,Plasmonics,Optical,Magnetic,and Hybrid Materials,Photocatalytic Hydrogen Evolution
更新于2025-09-23 15:22:29