Facile engineering of reduced graphene oxide-anchored nickel selenide and molybdenum selenide nanocomposite for dual functionality in seawater electrolysis and supercapacitor applications

Electrocatalytic water-splitting is a cost-effective and environmentally friendly method for producing high-purity hydrogen using renewable energy sources. Developing efficient and economical catalysts for the hydrogen evolution reaction (HER) is deemed essential for minimizing energy loss in water splitting. We propose that the NiSe₂/MoSe₂@rGO nanocomposite performs as an exceptional electrocatalyst for the HER and oxygen evolution reaction (OER) in an alkaline seawater electrolyte, exhibiting great activity and stability. The NiSe₂/MoSe₂@rGO nanocomposite-coated nickel foam (NF) electrode demonstrates an exceptionally low overpotential of 254 mV to reach a current density of 10 mA/cm², with the Tafel slope value of merely 225 mV/dec for the HER in alkaline seawater electrolyte. Similarly, it exhibits an overpotential of 350 mV at the 10 mA/cm² current density, with a Tafel slope of only 94 mV/dec for the OER, both of which are inferior to those of NiSe₂, MoSe₂, and GO catalysts. Furthermore, the very flexible material exhibits no significant catalytic degradation after 12 and 24 h of amperometric i-t curves at current densities of 20 and 40 mA/cm², thereby affirming its exceptional flexibility and durability under extreme conditions. The NiSe₂/MoSe₂@rGO nanocomposite demonstrated a remarkable capacitance of 41.8C/g, surpassing the performance of NiSe₂, MoSe₂, and GO catalysts. Additionally, the GCD stability over 4000 cycles indicated exceptional stability at a current density of 10 A/g when utilizing the optimally performing NiSe₂/MoSe₂@rGO nanocomposite coated NF electrode. Consequently, the synthesized material shows promise as an effective electrode material for high-efficiency energy generation and storage applications.