Engineering cobalt nickel oxide nanowires embedded in tungsten disulfide/reduced graphene oxide hybrid composites for supercapacitor applications and overall water-splitting reactions

Abstract

This paper presents the fabrication of hierarchical hollow 3D nanowires-like cobalt nickel oxide nanowires (NWs) embedded in tungsten disulfide/reduced graphene oxide hybrid (CoNiO₂@WS₂/rGO) composite through a facile hydrothermal process. The interaction between the 3D hollow WS₂/rGO skeleton network and the well-defined CoNiO₂ NWs enabled the remarkable electrochemical supercapacitor performances constructed with an enriched specific capacity (515C/g at 0.5 A/g) and superior cycling solidity (97.5 %). Asymmetric device assembled engaging the CoNiO₂@WS₂/rGO composite displayed a 236F/g specific capacitance at 1 A/g with ∼74 Wh/kg energy density at 2.4 kW/kg power density along with a high cycling stability (95.2 %). Furthermore, CoNiO₂@WS₂/rGO composite possessed bundles of pores with strong interfacial connection, and this enabled a large accessible surface area on the nanowires and facilitated the release of gas bubbles, resulting in excellent oxygen evolution and hydrogen evolution kinetics with a small overpotential (η₁₀ = 195 and 33 mV, respectively). Assembled CoNiO₂@WS₂/rGO (+/-) electrolyzer achieved a current density of 10 mA cm⁻² at a minimal cell voltage of 1.43 with long-span strength. Additionally, theoretical computation studies confirmed that the exceptional catalytic efficacy of the fabricated catalyst could be attributed to the transfer of charge from WS₂/rGO to CONiO₂ NWs.