Modification of TiO nanotubes by graphene-strontium and cobalt molybdate perovskite for efficient hydrogen evolution reaction in acidic medium.

Herein, we demonstrate that modification of TiO nanotubes with graphene-strontium and cobalt molybdate perovskite can turn them into active electrocatalysts for hydrogen evolution reaction (HER). For this purpose, a simple method of hydrothermal synthesis of perovskites was developed directly on the TiO nanotubes substrate. Moreover, the obtained hybrids were also decorated with graphene oxide (GO) during one-step hydrothermal synthesis. The obtained materials were characterized by scanning electron microscopy with energy dispersive X-ray analysis, Raman spectroscopy, and X-ray diffraction analysis. Catalytic properties were verified by electrochemical methods (linear voltammetry, chronopotentiometry). The obtained hybrids were characterized by much better catalytic properties towards hydrogen evolution reaction compared to TiO and slightly worse than platinum. The optimized hybrid catalyst (decorated by GO) can drive a cathodic current density of 10 mA cm at an overpotential of 121 mV for HER with a small Tafel slope of 90 mV dec in 0.2 M HSO.