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Enhancing Electrocatalytic Water Splitting Activities via Photothermal Effect over Bifunctional Nickel/Reduced Graphene Oxide Nanosheets
摘要： Electrocatalytic water splitting has huge potential for generating hydrogen fuel. Its wide application suffers from high energy loss and sluggish reaction kinetics. The adoption of appropriate electrocatalysts is capable of reducing the overpotential and accelerating the reaction. Present research mainly focuses on adjusting electrocatalysts, but the performances are also dependent on other parameters. Therefore, the development of an efficient strategy to enhance electrocatalytic performance through integrating with other driving force, especially a renewable driving force, is of great interest. Herein, we present a photothermal-effect-driven strategy to promote the electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities of nickel/reduced graphene oxide (denoted as Ni/RGO) bifunctional electrocatalysts. The Ni/RGO composite exhibited significant enhancement of activities after exposure to light irradiation (49 mV and 50 mV decrease of overpotential at 10 mA/cm2 for HER and OER, respectively). It was found that the improved electrocatalytic activities arose from the photothermal effect of Ni/RGO, which can efficiently facilitate the thermodynamics and kinetics of electrocatalytic reactions. Furthermore, the photothermal-effect-induced enhancement for electrocatalysis showed good stability, indicating its promising potential in practical application.
关键词： Bifunctional electrocatalysts,Oxygen evolution reaction,Ni/RGO nanosheets,Photothermal effect,Hydrogen evolution reaction
更新于2025-09-19 17:15:36
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A Highly Efficient and Durable Water Splitting System: Platinum Sub-Nanoclusters Functionalized Nickel Iron Layered Double Hydroxides as the Cathode and Hierarchical Nickel Iron Selenides as the Anode
摘要： Developing cost-efficient and effective catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remains a great challenge for the applications of high-efficiency water electrolyzers. In this work, we design a highly efficient and durable water splitting system in an alkaline solution, of which the platinum (Pt) sub-nanoclusters (average size: 0.59 nm) functionalized nickel iron layered double hydroxide nanosheets on carbon fiber cloth (Pt-NiFe LDH/CC) serve as the cathode and the hierarchical (Ni0.77Fe0.23)Se2 nanosheets on CC ((Ni0.77Fe0.23)Se2/CC) act as the anode. For the HER, the three-dimensional (3D) Pt-NiFe LDH/CC electrode with an ultralow Pt content (1.56 wt%) drives a current density of 10 mA cm-2 under an ultralow overpotential of 28 mV. For the OER, the edge-rich (Ni0.77Fe0.23)Se2/CC electrode displays a current density of 10 mA cm?2 under a small overpotential of 228 mV, and the Tafel slope is as low as 69 mV dec?1. More importantly, the assembled Pt-NiFe LDH/CC || (Ni0.77Fe0.23)Se2/CC water splitting electrolyzer exhibits a high current density of 30 mA cm?2 at a low cell voltage of 1.57 V, which is superior than that of electrolyzer assembled by the commercial 20 wt% Pt/C and RuO2 electrodes (30 mA cm?2 at 1.62 V). Additionally, the Pt-NiFe LDH/CC || (Ni0.77Fe0.23)Se2/CC electrolyzer displays excellent stability over 40 hours even at a high current density of 50 mA cm?2, which shows a great potential in the practical applications of full water splitting.
关键词： Hydrogen Evolution Reaction,Platinum Sub-Nanoclusters,Oxygen Evolution Reaction,NiFe Layered Double Hydroxide,Porous NiFe Selenide
更新于2025-09-19 17:15:36
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Metal-ion bridged high conductive RGO-M-MoS2 (M = Fe3+, Co2+, Ni2+, Cu2+ and Zn2+) composite electrocatalysts for photo-assisted hydrogen evolution
摘要： Efficient photo-electrocatalysts for hydrogen evolution reaction (HER) are synthesized using a facile one-step hydrothermal method. With metal-ion bridges, highly dispersed molybdenum disulfide (MoS2) nanolayers are vertically grown on the reduced graphene oxide (RGO) to form RGO-M-MoS2 photocatalysts for HER, where M = Fe3+, Co2+, Ni2+, Cu2+ and Zn2+. The results show that the cross-bridging ions can modulate the MoS2 growth priority and act as efficient charge transfer channels between RGO and MoS2, and combine the advantages of the high conductivity of graphene with the photo-electrochemical activity of MoS2. The metal-ion bridged MoS2-M-RGO heterostructures demonstrate superior catalytic activity toward hydrogen evolution reaction (HER) in acid medium, evidenced by the remarkable higher catalytic current density at low overpotential compared with that of MoS2-RGO without metal-ion bridge. This study provides a novel and facile route for establishing efficient composite photo-electrocatalysts for water splitting to generate hydrogen.
关键词： hydrogen evolution reaction,MoS2 nanosheets,reduced graphene oxide,metal-ion bridge
更新于2025-09-19 17:15:36
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Aligned Heterointerface-Induced 1T-MoS <sub/>2</sub> Monolayer with Near-Ideal Gibbs Free for Stable Hydrogen Evolution Reaction
摘要： 1T-phase molybdenum disulfide (1T-MoS2) exhibits superior hydrogen evolution reaction (HER) over 2H-phase MoS2 (2H-MoS2). However, its thermodynamic instability is the main drawback impeding its practical application. In this work, a stable 1T-MoS2 monolayer formed at edge-aligned 2H-MoS2 and a reduced graphene oxide heterointerface (EA-2H/1T/RGO) using a precursor-in-solvent synthesis strategy are reported. Theoretical prediction indicates that the edge-aligned layer stacking can induce heterointerfacial charge transfer, which results in a phase transition of the interfacial monolayer from 2H to 1T that realizes thermodynamic stability based on the adhesion energy between MoS2 and graphene. As an electrocatalyst for HER, EA-2H/1T/RGO displays an onset potential of ?103 mV versus RHE, a Tafel slope of 46 mV dec?1 and 10 h stability in acidic electrolyte. The unexpected activity of EA-2H/1T/RGO beyond 1T-MoS2 is due to an inherent defect caused by the gliding of S atoms during the phase transition from 2H to 1T, leading the Gibbs free energy of hydrogen adsorption (ΔGH*) to decrease from 0.13 to 0.07 eV, which is closest to the ideal value (0.06 eV) of 2H-MoS2. The presented work provides fundamental insights into the impressive electrochemical properties of HER and opens new avenues for phase transitions at 2D/2D hybrid interfaces.
关键词： 1T-MoS2 monolayers,stability,hydrogen evolution reaction,edge-aligned structure
更新于2025-09-19 17:15:36
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One-pot, solid-state loading of Zn into g-C3N4 for increasing the population of photoexcited electrons and the rate of photocatalytic hydrogen evolution
摘要： In this research, we load g-C3N4 with Zn through a simple, one-pot solid-state route that results in appreciably improved photocatalytic activity for H2 evolution under visible light. X-ray photoelectron spectroscopy and synchrotron X-ray absorption near edge structure spectroscopy confirm that the Zn species are present in the +2 oxidation state, coordinated to O atoms in the form of nanoclusters. Following the Zn loading, the host g-C3N4 absorbs more light in the UV and visible regions, while its physical features are almost unaltered. In the absence of any co-catalysts, a H2 evolution rate as high as 26.3 μmol/g·h can be achieved by g-C3N4 loaded with 0.2 atomic% of Zn, more than 8 times higher than that of g-C3N4 (3 μmol/g·h). Our results then provide strong evidences that the photocatalytic activity of Zn-loaded g-C3N4 for H2 evolution is directly controlled by the population of photoexcited electrons.
关键词： Zinc loading,Carbon nitride,Hydrogen evolution,Photocatalysis
更新于2025-09-19 17:15:36
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Comparison of TiO <sub/>2</sub> and g-C <sub/>3</sub> N <sub/>4</sub> 2D/2D nanocomposites from three synthesis protocols for visible-light induced hydrogen evolution
摘要： Knowledge of the interfacial structure of nanocomposite materials is a prerequisite for rational design of nanostructured photocatalysts. Herein, TiO2 and g-C3N4 2D/2D nanocomposites were fabricated from three distinct synthetic protocols (i.e., co-calcination, solvothermal treatment and charge-induced aggregation), showing different degrees of enhancement (1.4–6.1 fold) in the visible-light induced photocatalytic hydrogen evolution reaction compared to the simple physical mixture. We propose that the interfacial Ti–O–N covalent bonding promotes the charge carrier transfer and separation more effectively than the electrostatic interaction, thus accelerating the photocatalytic H2 production. Meanwhile, the exposed surface area of TiO2 in the composite needs to be enlarged for deposition of the co-catalyst. This research sheds light on the rational design of hybrid nanocomposites based on earth-abundant elements for photocatalysis.
关键词： visible light,TiO2,nanocomposites,g-C3N4,photocatalysis,hydrogen evolution
更新于2025-09-19 17:15:36
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Intercalated complexes of 1T′-MoS <sub/>2</sub> nanosheets with alkylated phenylenediamines as excellent catalysts for electrochemical hydrogen evolution
摘要： Two-dimensional layered MoS2 has recently been considered as an excellent catalyst for the water-splitting hydrogen evolution reaction (HER). Herein, we synthesize 1T0 phase MoS2 that was intercalated with a series of alkylated p-phenylenediamines (PDs). The substituted N atoms produced S vacancies, leading to a composition of MoS2-2xNx (x = 0.1). The more abundant methyl groups induce a larger charge transfer, resulting in excellent HER performance: for tetramethyl PD, the overpotential is 0.15 V at 10 mA cm-2 with a Tafel slope of 35 mV dec-1. The catalytic activity of the complexes depends on the concentration of the intercalated molecules, showing an optimum at a concentration of 8 mol%. First-principles calculations showed that the intercalated complexes (1T0 phase) having N atom–S vacancy (N–VS) pairs are stabilized by a large charge transfer from the PD molecules that is enhanced by the methyl groups (i.e., 0.40e–0.84e per molecule at 6.25 mol% intercalation). The charge transfer increases the density of states at and just above the Fermi level, thereby increasing the electron concentration at low cathodic bias. The active sites for the Volmer reaction are found to be N atoms in the proximal N–VS pairs. The activation barrier for the Heyrovsky reaction becomes higher at higher concentrations of the intercalants, suggesting that the experimental HER performance is also kinetically controlled.
关键词： catalysis,first-principles calculations,MoS2,hydrogen evolution reaction,intercalation
更新于2025-09-19 17:15:36
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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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One Pot Assembly of Vertical Embedded MoS2/Graphene Hetero-structure and Its High Performance for Hydrogen Evolution Reaction
摘要： Two-dimensional molybdenum disulfide has great potential to replace rare precious metals for hydrogen evolution reaction. Herein, we report a one pot assembly strategy for in-situ growing vertical embedded MoS2 nanocrystals on graphene surface. The resultant sandwiched architecture could not only expose more active sites within MoS2 edge, but also reduce stacking tendency of the layer-structured graphene support, leading to a significant improvement in HER performance. The materials showed an over-potential of 142 mV at 10 mA·cm?2 and a Tafel slope of 68 mV·dec?1, which are among the best results ever obtained by the similar materials. Moreover, this method is facile, environmental friendly and suitable for mess production, making it attractive for practical applications.
关键词： Graphene,Hydrogen evolution reaction,MoS2,Electrocatalysis,Sandwiched structure
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