Unveiling of cost-effective non-noble binary metal selenide-decorated graphene oxide composite electrode for high-performance electrochemical and photoelectrochemical water splitting

The pursuit of efficient and sustainable energy conversion has driven significant research on the development of advanced electrode materials for photoelectrochemical (PEC) water splitting. In this study, we present a novel composite material composed of Z-type multifaceted CuSe and FeSe2 binary metal selenide nanoparticles (NPs) decorated on a graphene oxide (GO) matrix as an active electrode material for high-performance PEC water splitting applications. The catalytic activity of copper-based catalysts is enhanced by the inclusion of iron (Fe) and selenium (Se), as these elements facilitate the creation of more robust covalent connections between the metal and anion. Further, the presence of an amalgamation of GO, which possesses a substantial surface area and excellent electrical conductivity, enhances oxygen evolution reaction (OER) efficiency. The electrode (i.e., CuSe-FeSe2@GO) demonstrated an exceptionally low overpotential of 16.3 mV at a current density of 10 mmA cm-2, a modest Tafel slope of 58.3 mV dec- 1, and a current density of 26.04 mA cm-2 in an alkaline aqueous solution under 1 Sun. The detection of superoxide radicals (O2-center dot) suggests the potential formation of Z-type heterojunctions between CuSe and FeSe2 NPs. Thus, this research offers a novel approach for the fabrication of resource-rich, economical, and highly active Cu-based catalysts for the OER.