Polypyrrole-Ru(2,2′-bipyridine)32+/MoSx Structured Composite Film As a Photocathode for the Hydrogen Evolution Reaction

The development of photoelectrochemical devices for solar light-driven water splitting and H-2 production requires new strategies for the fabrication of materials that combine the necessary photoredox and catalytic properties, to allow the hydrogen evolution reaction (HER) to take place at a low overvoltage under visible light irradiation. We report the first example of a structured composite, synthesized by electrodeposition of MoSx cocatalyst into a photosensitive Ru complex film deposited onto carbon electrodes by electropolymerization of a pyrrole-functionalized Ru-II(2,2'-bipyridine)(3)(2+). Composite films show efficient photocatalytic activity for HER. Our study highlights the great simplicity of this versatile electrochemical procedure to synthesize photocathodes.