RuO2-NaTaO3 heterostructure for its application in photoelectrochemical water splitting under simulated sunlight illumination

In this paper, we report the synthesis of RuO2-NaTaO3 films for their application as photocathodes in photoelectrochemical (PEC) cells for hydrogen generation from water splitting. RuO2 was electrodeposited on NaTaO3 films at constant current varying the deposition time with the finality to obtain 1-3 wt.% RuO2-NaTaO3. The characterization of the photoelectrodes RuO2-NaTaO3 was carried out by linear voltammetry (VL), chronoamperometry (CA), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS). The hydrogen production was conducted in a photoelectrochemical reactor coupled with a gas chromatograph. One of the main contributions of this work is the incorporation of RuO2 on NaTaO3 films in order to enhance its activity in the visible region, achieving a maximum photoelectrochemical hydrogen production of 15.7 mmol h−1 g−1 for the film with 2 wt.% RuO2 with a solar-to-hydrogen (STH) conversion efficiency of 4.29%.