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Integrating non-precious-metal cocatalyst Ni3N with g-C3N4 for enhanced photocatalytic H2 production in water under visible-light irradiation
摘要： Photocatalytic H2 production via water splitting in a noble-metal-free photocatalytic system has attracted much attention in recent years. In this study, noble-metal-free Ni3N was used as an active cocatalyst to enhance the activity of g-C3N4 for photocatalytic H2 production under visible-light irradiation (λ > 420 nm). The characterization results indicated that Ni3N nanoparticles were successfully loaded onto the g-C3N4, which accelerated the separation and transfer of photogenerated electrons and resulted in enhanced photocatalytic H2 evolution under visible-light irradiation. The hydrogen evolution rate reached ~305.4 μmol h?1 g?1, which is about three times higher than that of pristine g-C3N4, and the apparent quantum yield (AQY) was ~0.45% at λ = 420 nm. Furthermore, the Ni3N/g-C3N4 photocatalyst showed no obvious decrease in the hydrogen production rate, even after five cycles under visible-light irradiation. Finally, a possible photocatalytic hydrogen evolution mechanism for the Ni3N/g-C3N4 system is proposed.
关键词： Hydrogen evolution,g-C3N4,Cocatalyst,Ni3N,Photocatalysis
更新于2025-09-23 15:22:29
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Synthesis of non-noble metal nickel doped sulfide solid solution for improved photocatalytic performance
摘要： Bimetallic Sul?des, a series of versatile catalysts, are still hampered from putting into practical application due to the issue of the recombination of photogenerated charges. In this work, in order to enhance the light harvesting ability as well as ameliorate the separation and transportation of photo-induced charges at the same time, Ni ion was adopted to modify Zn0.5Cd0.5S catalyst. The subsequent photocatalytic water splitting tests showed that the H2 evolution rate over Ni doped Zn0.5Cd0.5S was 6 times higher than that achieved on the prestine Zn0.5Cd0.5S, indicating a signi?cant enhancement in catalytic activity. Furthermore, the selective oxidation of benzyl alcohol was also performed by the as-prepared catalysts under visible light irradiation. When 1% Ni ions were doped in Zn0.5Cd0.5S solid solution, the yield of product benzaldehyde was increased from 70% to 92%. The photoelectrochemical test suggests that the improved photocatalytic performance is presumably ascribed to the e?cient separation of photo-generated carriers. Additionally, DOS calculation con?rms the contribution of the improved light harvesting ability of Ni-doped Zn0.5Cd0.5S in the photocatalytic reaction. In all, this work presents that doping Ni into ZnS/CdS solid solution is a very useful technique to improve photocatalytic activity for two typical photocatalytic reactions-the H2 evolution and alcohol selective oxidation reaction.
关键词： Photocatalyst,Metal doping,Selective oxidation,Hydrogen evolution
更新于2025-09-23 15:22:29
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In situ derived Ni2P/Ni encapsulated in carbon/g-C3N4 hybrids from metal–organic frameworks/g-C3N4 for efficient photocatalytic hydrogen evolution
摘要： Tightly coupling multiple cocatalysts into semiconductors for efficient charge separation is a promising way to enhance photocatalytic H2 production. In this work, Ni2P/Ni nanoparticles (NPs) encapsulated in carbon/g-C3N4 hybrids derived from in situ pyrolysis and phosphidation of Ni-based metal-organic frameworks/g-C3N4 (Ni-MOF/g-C3N4) precursor were used as photocatalysts for H2-evolution under visible-light irradiation. The highest H2-evolution rate over optimized Ni2P/Ni@C/g-C3N4-550 was 18.04 mmol g?1 h?1 with 1.0 mmol L?1 of Eosin Y (EY)-sensitization (compared to 0.21 mmol g?1 h?1 without EY-sensitization), 13 times higher than that of pristine g-C3N4 (1.33 mmol g?1 h?1). The apparent quantum efficiency at 420 nm was 58.1%. This enhanced photocatalytic activity can be attributed to an efficient and rapid separation of the photo-generated charges from excited EY and g-C3N4 to Ni2P/Ni with carbon as an electron transport bridge, intimate contact of each components, staggered band alignment among g-C3N4, Ni and Ni2P, as well as accelerated proton reduction reaction by Ni2P/Ni NPs. This work provides new insights into the construction of MOFs-derived cocatalyst for photocatalytic H2 production.
关键词： H2 evolution,g-C3N4,Ni-MOF-derived,carbon materials,Ni2P/Ni
更新于2025-09-23 15:22:29
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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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Cross-correlation of cosmic far-infrared background anisotropies with large scale structures
摘要： We measure the cross-power spectra between luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS)-III data release 8 (DR8) and cosmic infrared background (CIB) anisotropies from Planck and data from the Improved Reprocessing (IRIS) of the Infrared Astronomical Satellite (IRAS) at 353, 545, 857, and 3000 GHz, corresponding to 850, 550, 350 and 100 μm, respectively, in the multipole range 100 < l < 1000. Using approximately 6.5 × 10^5 photometrically determined LRGs in 7760 deg^2 of the northern hemisphere in the redshift range 0.45 < z < 0.65, we model the far-infrared background (FIRB) anisotropies with an extended version of the halo model. With these methods, we confirm the basic picture obtained from recent analyses of FIRB anisotropies with Herschel and Planck that the most efficient halo mass at hosting star forming galaxies is log(Meff/M☉) = 12.84 ± 0.15. We estimate the percentage of FIRB anisotropies correlated with LRGs as approximately 11.8%, 3.9%, 1.8%, and 1.0% of the total at 3000, 857, 545, and 353 GHz, respectively. At redshift z ～ 0.55, the bias of FIRB galaxies with respect to the dark matter density field has the value bFIRB ～ 1.45, and the mean dust temperature of FIRB galaxies is Td = 26 K. Finally, we discuss the impact of present and upcoming cross-correlations with far-infrared background anisotropies on the determination of the global star formation history and the link between galaxies and dark matter.
关键词： galaxies: statistics,large-scale structure of Universe,galaxies: evolution,cosmic background radiation,infrared: diffuse background
更新于2025-09-23 15:22:29
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Do cluster properties affect the quenching rate?
摘要： The quenching rate is known to depend on galaxy stellar mass and environment, however, possible dependences on the hosting halo properties, such as mass, richness, and dynamical status, are still debated. The determination of these dependences is hampered by systematics, induced by noisy estimates of cluster mass or by the lack of control on galaxy stellar mass, which may mask existing trends or introduce fake trends. We studied a sample of local clusters (20 with 0.02 < z < 0.1 and log(M200/M(cid:3)) (cid:2) 14), selected independent of the galaxy properties under study, having homogeneous optical photometry and X-ray estimated properties. Using those top quality measurements of cluster mass, hence of cluster scale, richness, iron abundance, and cooling time/presence of a cool-core, we study the simultaneous dependence of quenching on these cluster properties on galaxy stellar mass M and normalised cluster-centric distance r/r200. We found that the quenching rate can be completely described by two variables only, galaxy stellar mass and normalised cluster-centric distance, and is independent of halo properties (mass, richness, iron abundance, and central cooling time/presence of a cool-core). These halo properties change, in most cases, by less than 3% the probability that a galaxy is quenched, once the mass-size (M200 – r200) scaling relation is accounted for through cluster-centric distance normalisation.
关键词： galaxies: star formation,galaxies: evolution,galaxies: clusters: general
更新于2025-09-23 15:22:29