Light-Driven Photocatalytic Hydrogen Evolution on Spindle-like MoSx Nanostructures Grown on Poly-Salicylic Acid Synthesized through Bipolar Electrochemistry

Transition metal chalcogenides (TMCs) such as molybdenum sulfide are scientifically and economically considered because of their abundance and capability in electronics, catalysis, and so on. On the other hand, conducting polymers have displayed unique properties and have been widely used in chemistry and materials science. Here, a facile electrochemical route, called bipolar electrochemistry (BPE), is employed to fabricate the MoSx catalyst integrated with a poly-salicylic acid (PSA), as a catalyst support, to enhance the electron transfer characteristics. Electropolymerization was used to prepare PSA on the anodic pole of BP gold microfilm, followed by the BPE electrodeposition of MoSx on the first-designed PSA substrate. Characterization of the as prepared integrated system reveals a thin layer of spindle-like MoSx nanostructures arranged on a gold microfilm. The PSA offers a synergistic effect in the integrated system of MoSx/PSA, which significantly decreases the hydrogen reduction overpotential with an onset potential of -0.04 V vs reversible hydrogen electrode (RHE) and Tafel slope of 0.62 V dec(-1) in 0.5 M H2SO4. More importantly, the prepared electrode displays the characteristic of dye-sensitized photocathode, applicable for sustainable energy conversion, since under light irradiation the hydrogen evolution reaction (HER) begins at +0.16 V vs RHE.