Nano-interfaced tungsten oxide decorated on layered double hydroxides for the oxygen evolution reaction

Abstract

Layered double-hydroxides (LDHs) have emerged as a benchmark catalyst for the oxygen evolution reaction (OER). To accelerate the reaction kinetics for the OER, it becomes important to design a hybrid interfacial material with an improved synergistic effect. In this work, Co–Fe layered double-hydroxide nanosheets are synthesized where WO₃ nanoparticles (NPs) were introduced on the nanosheets using an appropriately planned hydrothermal reaction. When the molar ratio of Co : Fe : W precursors is kept at 3 : 1 : 0.1 during the synthesis of the catalyst, the activity of the catalyst synthesized was found to be the best. Herein, it was observed that the oxygen evolution reaction (OER) gets enhanced abruptly when tungsten oxide NPs were formed on the surface of the CoFeLDH nanosheet. The catalyst operates with an overpotential of 270 mV to drive a current density of 20 mA cm⁻², exhibiting a Tafel slope value of 120 mV dec⁻¹. The catalyst is extremely stable and has shown a long-term stability of more than 120 h at 10 mA cm⁻² in an alkaline medium. This work opens up a wide avenue to modify LDHs with a third metal ion, which improves the performance of the catalyst.