Palladinized graphene oxide-MOF induced coupling of Volmer and Heyrovsky mechanisms, for the amplification of the electrocatalytic efficiency of hydrogen evolution reaction

Modification of TiO2 nanotubes by graphene-strontium and cobalt molybdate perovskite for efficient hydrogen evolution reaction in acidic medium

Herein, we demonstrate that modification of TiO₂ 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 TiO₂ 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 TiO₂ and slightly worse than platinum. The optimized hybrid catalyst (decorated by GO) can drive a cathodic current density of 10 mA cm^-2 at an overpotential of 121 mV for HER with a small Tafel slope of 90 mV dec^-1 in 0.2 M H₂SO₄.