Three-dimensional bimetal TMO supported carbon based electrocatalyst developed via dry synthesis for hydrogen and oxygen evolution

Abstract The rational design of highly efficient bifunctional electrocatalysts for the oxygen and hydrogen evolution reactions is still an ongoing challenge. Herein, bimetallic transition metal oxide incorporated three-dimensional (3D) nitrogen-doped graphene/carbon nanotube (CNT) conductive matrix has been developed via dry synthesis and applied as a potential catalyst for the oxygen and hydrogen evolution reactions. The key features of the structure as well as its 3D network, nitrogen doping, and metal oxide formation were confirmed using various characterization techniques such as scanning electron and transmission electron microscopies, X-ray diffraction, and X-ray photoelectron spectroscopy. A nickel cobalt oxide-incorporated 3D nitrogen-doped graphene/CNT conductive matrix (NCGC) exhibits low overpotentials of 290 and 214 mV at 10 mA cm−2 to drive the oxygen and hydrogen evolution reactions, respectively. Furthermore, the NCGC electrocatalyst maintains a reasonably long-term water electrolysis performance over 20 h, thought to be as a result of an improvement in the activity and stability of NCGC through the synergetic effects of the bimetallic transition oxide and 3D nitrogen-doped graphene/CNT. The overall electrochemical activity and stability of the prepared NCGC make it a good economical substitute for commercial noble metal-based catalysts for use in renewable energy production.