Electrocatalytic studies of siloxene sheets encrusted with cobalt chalcogenides (S, Se) for water splitting

Abstract

Two-dimensional siloxene sheets were superficially coated with cobalt chalcogenides to optimize interfacial properties for broad applications in the field of catalysis. These catalytic composites were investigated for electrochemical water splitting in an alkaline electrolyte medium. The synthesis of siloxene sheet-cobalt chalcogenides composites was confirmed by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, adsorption studies, and X-ray photoelectron spectroscopy analyses. Potentiometric and impedimetric experiments were performed to understand the inherent electrocatalytic activity of the developed catalysts. Variations in the onset potential and overpotential at a constant current density of ±10 mA/cm2 for hydrogen and oxygen evolution reactions—HER and OER, respectively—were evaluated with respect to a reversible hydrogen electrode (RHE). The catalysts exhibit superior current and catalytic activity due to interfacial kinetics, retaining lower Tafel slopes of ∼30 mV/dec for the OER and HER; they also exhibited improved, long-term stability for 12 h, indicating potential utility in commercial applications. © 2022 Hydrogen Energy Publications LLC