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Oxygen doped MoS <sub/>2</sub> quantum dots for efficient electrocatalytic hydrogen generation
摘要： In this study, we report an oxygen-doped MoS2 quantum dot (O–MoS2 QD) hybrid electrocatalyst for the hydrogen evolution reaction (HER). The O–MoS2 QDs were prepared with a one-pot microwave method by hydrazine-mediated oxygen-doping. The synthetic method is straightforward, time-saving, and can be applied in large scale preparation. Ultra-small O–MoS2 QDs with the average size of 5.83 nm and 1–4 layers can be uniformly distributed on the surface of reduced graphene oxide (RGO). Benefited from the unique structure and the doping effect of oxygen in the MoS2 QDs and the great number of active sites, the O–MoS2 QD hybrid displayed outstanding electrocatalytic performance toward HER. A low overpotential of 76 mV at 10 mA/cm2 and a Tafel slope of 58 mV/dec were obtained in an acidic solution toward HER. Additionally, the resultant O–MoS2 QD hybrid also exhibited excellent stability and durability toward HER, displaying negligible current density loss after 1000 cycles of cyclic voltammetry. The design and synthesis of the electrocatalyst in this work open up a prospective route to prepare active and stable electrocatalysts toward substituting precious metals for hydrogen generation.
关键词： electrocatalytic hydrogen generation,oxygen-doped MoS2 quantum dots,microwave synthesis,reduced graphene oxide,hydrogen evolution reaction
更新于2025-09-19 17:13:59
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Hierarchical Ni-MoSex@CoSe2 core-shell nanosphere as highly active bifunctional catalyst for efficient dye-sensitized solar cell and alkaline hydrogen evolution
摘要： Core-shell structured nanocomposites based on transition metal selenides have a broad development prospect as Pt-free electrocatalyst in energy conversion due to large surface area, rich edge sites, as well as synergistic interactions between the core and shell. Herein, the preparation of core-shell structured transition metal selenides nanospheres was achieved through a facile wrapping process using zeolitic imidazolate framework (ZIF-67) as the cobalt source, which assembled on glycerol precursor nanospheres. After a selenization treatment, this formed core-shell structure had a Ni-MoSex inner core, supporting the CoSe2 outer shell (denoted as Ni-MoSex@CoSe2 CSNs). And the resultant Ni-MoSex@CoSe2 CSNs not only had a large number of active sites, but also was good for adsorbing/transferring iodine and hydrogen ions. Therefore, Ni-MoSex@CoSe2 delivered superior performance in dye-sensitized solar cells (DSSCs) and alkaline hydrogen evolution reactions (HERs). DSSCs based on Ni-MoSex@CoSe2 CSNs performed an outstanding power conversion efficiency (PCE) of 9.58% which was much higher than that of Pt (8.32%). A lower onset potential of 37.5 mV and a smaller Tafel slope of 68.9 mV dec?1 were achieved by Ni-MoSex@CoSe2 as electrocatalysts for HER in 1.0 M KOH. This work affords a new idea for the design of cut-price core-shell nanomaterials with high efficiency and can be extended to the synthesis of other electrocatalysts substituting Pt-based catalysts.
关键词： Hydrogen evolution,Core-shell nanosphere,Bifunctional catalyst,Dye-sensitized solar cell,Ni-MoSex@CoSe2,Transition metal selenide
更新于2025-09-19 17:13:59
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Comparative Study of the Structure, Composition, and Electrocatalytic Performance of Hydrogen Evolution in MoSx~2+?′/Mo and MoSx~3+?′ Films Obtained by Pulsed Laser Deposition
摘要： Systematic and in-depth studies of the structure, composition, and efficiency of hydrogen evolution reactions (HERs) on MoSx films, obtained by means of on- and off-axis pulsed laser deposition (PLD) from a MoS2 target, have been performed. The use of on-axis PLD (a standard configuration of PLD) in a buffer of Ar gas, with an optimal pressure, has allowed for the formation of porous hybrid films that consist of Mo particles which support a thin MoSx~2+δ (δ of ~0.7) film. The HER performance of MoSx~2+δ/Mo films increases with increased loading and reaches the highest value at a loading of ~240 μg/cm2. For off-axis PLD, the substrate was located along the axis of expansion of the laser plume and the film was formed via the deposition of the atomic component of the plume, which was scattered on Ar molecules. This made it possible to obtain homogeneous MoSx~3+δ (δ~0.8–1.1) films. The HER performances of these films reached saturation at a loading value of ~163 μg/cm2. The MoSx~3+δ films possessed higher catalytic activities in terms of the turnover frequency of their HERs. However, to achieve the current density of 10 mA/cm2, the lowest over voltages were ?162 mV and ?150 mV for the films obtained by off- and on-axis PLD, respectively. Measurements of electrochemical characteristics indicated that the differences in the achievable HER performances of these films could be caused by their unique morphological properties.
关键词： nanocatalysts,buffer gas,pulsed laser deposition,transition metal chalcogenides,hydrogen evolution reaction
更新于2025-09-19 17:13:59
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Tandem Si Micropillar Array Photocathodes with Conformal Copper Oxide and a Protection Layer by Pulsed Laser Deposition
摘要： This work demonstrates the influence of high-quality protection layers on Si-Cu2O micropillar arrays created by pulsed laser deposition (PLD), with the goal to overcome photodegradation and achieve long-term operation during photoelectrochemical (PEC) water splitting. Sequentially, we assessed planar and micropillar device designs with various design parameters and their influence on PEC hydrogen evolution reaction. On the planar device substrates, a Cu2O film thickness of 600 nm and a Cu2O/CuO heterojunction layer with a 5:1 thickness ratio between Cu2O to CuO were found to be optimal. The planar Si/Cu2O/CuO heterostructure showed a higher PV performance (Jsc = 20 mA/cm2) compared to the planar Si/Cu2O device, but micropillar devices did not show this improvement. Multifunctional overlayers of ZnO (25 nm) and TiO2 (100 nm) were employed by PLD on Si/Cu2O planar and micropillar arrays to provide a hole-selective passivation layer that acts against photocorrosion. A micropillar Si/ITO-Au/Cu2O/ZnO/TiO2/Pt stack was compared with a planar device. Under optimized conditions, the Si/Cu2O photocathode with Pt as a HER catalyst displayed a photocurrent of 7.5 mA cm?2 at 0 V vs RHE and an onset potential of 0.85 V vs RHE, with a stable operation for 75 h.
关键词： tandem photocathode,copper oxide,Si micropillar array,hydrogen evolution reaction,pulse laser deposition
更新于2025-09-19 17:13:59
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Noble-metal-free MoS2 nanosheet-coupled MAPbI3 photocatalyst for efficient and stable visible-light-driven hydrogen evolution
摘要： We report that MoS2 nanosheets (MoS2 NSs) as an cocatalyst in situ coupled with MAPbI3 leads to a highly efficient composite photocatalyst for visible-light-driven photocatalytic H2 evolution. The most efficient MAPbI3/MoS2 NSs exhibits a high H2 evolution rate (206.1 μmol h-1) in MAPbI3-saturated HI solution, which is 121 times higher than that of pristine MAPbI3 (1.7 μmol h-1) and greatly superior to that of MAPbI3/Pt/C (68.5 μmol h-1), and the composite is very stable for H2 evolution in 156 h reaction.
关键词： photocatalyst,MoS2 nanosheets,visible-light-driven,MAPbI3,hydrogen evolution
更新于2025-09-19 17:13:59
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Direct growth of high-content 1T phase MoS2 film by pulsed laser deposition for hydrogen evolution reaction
摘要： The modified MoS2-based material, with a higher conductivity and rich active sites, is promising one of a variety of nonprecious-metal electrocatalysts for hydrogen evolution reaction (HER). Here, the bulk MoS2 is exfoliated to form small-size MoS2 clusters by pulse laser, which are diluted in solid sulfur and further to form porous film. The 1T phase MoS2 ratio in the prepared film was modulated by adding the different content of sulfur into MoS2 target. Besides, this addition also has an effect on the pore structure of films. Finally, the obtained high-content 1T phase MoS2 film provides the highly metallic conductivity and more active sites, which results in the more enhanced HER catalytic activity with a lower Tafel slope of 38 mV dec-1, a smaller overpotential of 151 mV at 10 mA cm-2, compared with the pure MoS2 film.
关键词： pulsed laser deposition,sulfur addition,1T phase MoS2,Hydrogen evolution reaction
更新于2025-09-19 17:13:59
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Photocatalysts for Hydrogen Evolution Coupled with Production of Valuea??Added Chemicals
摘要： The conversion of water into clean hydrogen fuel using renewable solar energy can potentially be used to address global energy and environmental issues. However, conventional photocatalytic H2 evolution from water splitting has low efficiency and poor stability. Hole scavengers are therefore added to boost separation efficiency of photoexcited electron–hole pairs and improve stability by consuming the strongly oxidative photoexcited holes. The drawbacks of this approach are increased cost and production of waste. Recently, researchers have reported the use of abundantly available hole scavengers, including biomass, biomass-derived intermediates, plastic wastes, and a range of alcohols for H2 evolution, coupled with value-added chemicals production using semiconductor-based photocatalysts. It is timely, therefore, to comprehensively summarize the properties, performances, and mechanisms of these photocatalysts, and critically review recent advances, challenges, and opportunities in this emerging area. Herein, this paper: 1) outlines reaction mechanisms of photocatalysts for H2 evolution coupled with selective oxidation, C–H activation and C–C coupling, together with nonselective oxidation, using hole-scavengers; 2) introduces equations to compute conversion/selectivity of selective oxidation; 3) summarizes and critically compares recently reported photocatalysts with particular emphasis on correlation between physicochemical characteristics and performances, together with photocatalytic mechanisms, and; 4) appraises current advances and challenges.
关键词： C–C coupling,C–H activation,selective oxidation,photocatalysis,hydrogen evolution
更新于2025-09-19 17:13:59
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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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Plasmonic Au nanoparticle-decorated Bi2Se3 nanoflowers with outstanding electrocatalytic performance for hydrogen evolution
摘要： Hydrogen production from water splitting through electrocatalytic or photoelectrochemical route shows great potential for renewable energy conversion. Herein, the plasmon-enhanced photoelectrical nanocatalysts (NCs) have been successfully developed by Au nanoparticle-decorated Bi2Se3 nanoflowers (Au@Bi2Se3 NFs) as catalysts for hydrogen evolution reaction (HER), leading to a more than 3-fold increase of current under excitation of Au localized surface plasmon resonance (LSPR) and affording a markedly decreased overpotential of 375 mV at a current density of 10 mA cm?2. The HER enhancement can be largely attributed to effective electron-charge separation and the increase of carrier density in Bi2Se3 induced by the injection of hot electrons of Au nanoparticles. Meanwhile, Bi2Se3 nanoflowers (NFs), a kind of topological insulators, possess gapless edges on boundary and show metallic character on surface, providing a path for the flow of electrons in the electrocatalytic system. This study opens up a new avenue towards the design of higher energy conversion catalytic water splitting systems with the assistance of light energy, which could increase of HER catalysis efficiency by plasmonic excitation.
关键词： Hydrogen evolution reaction,Plasmonic,Bi2Se3,Au
更新于2025-09-16 10:30:52
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Pulsed Laser Deposition of Nanostructured MoS3/np-Mo//WO3?y Hybrid Catalyst for Enhanced (Photo) Electrochemical Hydrogen Evolution
摘要： Pulsed laser ablation of MoS2 and WO3 targets at appropriate pressures of background gas (Ar, air) were used for the preparation of new hybrid nanostructured catalytic ?lms for hydrogen production in an acid solution. The ?lms consisted of a nanostructured WO3?y underlayer that was covered with composite MoS3/np-Mo nanocatalyst. The use of dry air with pressures of 40 and 80 Pa allowed the formation of porous WO3?y ?lms with cauli?ower- and web-like morphology, respectively. The ablation of the MoS2 target in Ar gas at a pressure of 16 Pa resulted in the formation of amorphous MoS3 ?lms and spherical Mo nanoparticles. The hybrid MoS3/np-Mo//WO3?y ?lms deposited on transparent conducting substrates possessed the enhanced (photo)electrocatalytic performance in comparison with that of any pristine one (MoS3/np-Mo or WO3?y ?lms) with the same loading. Modeling by the kinetic Monte Carlo method indicated that the change in morphology of the deposited WO3?y ?lms could be caused by the transition of ballistic deposition to di?usion limited aggregation of structural units (atoms/clusters) under background gas pressure growth. The factors and mechanisms contributing to the enhancement of the electrocatalytic activity of hybrid nanostructured ?lms and facilitating the e?ective photo-activation of hydrogen evolution in these ?lms are considered.
关键词： pulsed laser deposition,tungsten oxides,transition metal chalcogenides,nanocatalysts,hydrogen evolution reaction,background gas
更新于2025-09-16 10:30:52