Theoretical and experimental study of flower-like NiMoS/NiO/NF with interface layer as a novel highly efficient bifunctional-electrode toward supercapacitor and HER

Abstract

Electrocatalytic water splitting and supercapacitor systems are considered one of the most imperative sustainable energy storage and conversion technologies as an alternative clean energy carrier/source to fossil fuels in order to address the pressing global warming problems. For achieving sustainable electrochemistry devices, highly efficient and superior durability electrocatalysts must be prepared through a facile and controllable approach. This study successfully demonstrated the development of a binder-free 3D- flower-like amorphous structure composite with self-assembled nanosheets supported on Nickel foam (NiMoS/NiO/NF) by a simple two-step hydrothermal technique as advanced electrocatalysts for alkaline hydrogen evolution reaction (HER) and supercapacitor. The as-obtained NiMoS/NiO/NF only needs a overpotential of 43 mV vs. RHE to reach 10 mA.cm−2 and remained stable after long-term HER tests. In the following, the nanostructure was operated as an electrode in the supercapacitor. According to the Galvanostatic Charge-Discharge (GCD) teats, the specific capacitance of NiMoS/NiO/NF was measured as 999F/g. Such outstanding NiMoS/NiO/NF performance can be ascribed to the synthesis of the interface layer (NiO), which makes the robust adhesion between NF and the final layer (NiMoS). The amorphous morphology with multi-component doping and heterojunctions, optimizes the hydrogen desorption sites, which leads to significant HER catalytic activity. The present experimental results and density functional theory (DFT) study offer a cost-effective, and convenient pathway to produce highly efficient non-nobel-based metal as high-valued multifunctional materials.