Transition Metal Molybdenum Sulfide Nanosheet Arrays As Catalyst For Hydrogen Evolution

The Metal-Molybdenum Sulfide is a promising non-noble metal hydrogen evolution catalyst with high catalytic activity and excellent stability.In this paper,an anion exchange strategy was employed to fabricate high-performance self-supporting amorphous Cu Mo S_x and NiMoS_x nanosheet arrays on the surface copper foam(CF)and nickel foam(NF),respectively.In this paper,various characterization methods,such as XRD,SEM,TEM,XPS,IR and Raman,were employed to analyze the morphology,crystal structure,elemental calence and composition of these two catalysts on the surface of electrode and their precursor,Cu TCNQ and Ni TCNQ.In addition,the catalytic activity,reaction kinetics and stability of these two electrodes for hydrogen evolution reaction were tested by a series of electrochemical methods such as cyclic voltammetry,linear sweep voltammetry,electrochemical impedance analysis,chronopotentiometry and chronoamperometry.Besides,The Double layered capacitive was measured to determine electrochemically active surface area which is ued to normalize the polarization curves.The Faraday efficiency was measured by gas chromatography spectrum.The electrode NiMoS_x/CF performed excellent hydrogen evolution activity in 0.5 M H₂SO₄ aqueous solution,and the required overpotential is 174 m V and 248 m V vs RHE at the current density of 10 and 50 m A·cm^-2,respectively,which is better than the electrode Cu Mo S_x/CF at the same condition(213 m V and 275 m V,respectively).The kinetics results showed that the Tafel slopes of the electrodes Cu Mo S_x/CF and NiMoS_x/C were 78.5 and 94.0m V·dec^-1,respectively,which means that the catalyst Cu Mo S_x has a faster catalytic hydrogen evolution rate.Moreover,Cu Mo S_x/CF and NiMoS_x/NF electrodes exhibited considerable long-term electrochemical durability,which could keep a stable potential for 25 and 24 hours at a constant current density of 10 m A·cm^-2.And these two could electrolyzed continuously for 23 and 21 hours under potentiostatic tests.In this paper,an effective and easy-to-operate strategy to construct self-supported M-Mo S_x nanosheet array films was provided to achieve efficient(photo)electrochemical hydrogen evolution reactions.