FeNi2Se4-Reduced Graphene Oxide Nanocomposite: Enhancing Bifunctional Electrocatalytic Activity for Oxygen Evolution and Reduction through Synergistic Effects

Water splitting reaction using earth-abundant and environmentally benign catalysts is critical for renewable energy generation and storage. Herein a hybrid composite, FeNi2Se4 nanoparticles supported on nitrogen doped reduced graphene oxide (FeNi2Se4-NrGO) is reported as an efficient and dependable bifunctional electrocatalyst for oxygen evolution and oxygen reduction reactions (OER and ORR, respectively) under alkaline conditions. While FeNi2Se4 nanoparticles themselves show good catalytic activity for water oxidation, the constructed hybrid nanocomposite with NrGO as the supporting matrix show enhanced catalytic activity with a small overpotential of 170 mV @ 10 mA cm(-2), small Tafel slope of 62.1 mV per decade, and high current density. The ORR catalytic activity of the nanocomposite catalyst is also good with an onset potential of 0.93 V. This is possibly due to the synergistic chemical coupling effects between the FeNi2Se4 and NrGO matrix. Chronoamperometric studies show that the catalyst is stable under conditions of continuous O-2 evolution and reduction with very less degradation. Apart from reporting highly efficient OER-ORR bifunctional catalyst, this study also provides more proof for the effect of anion coordination on the catalyst performance, as well as the synergistic role of nanoscale interactions between the catalyst particles and graphene matrix to enhance catalytic activity.