Ternary iron-cobalt-molybdenum hybrid for synergistically enhanced electrochemical water oxidation

Multi-metal hybrids with metastable and tunable electronic structures, show great promise in the electrocatalysis applications. In this study, we synthesize a ternary amorphous FeCoMo/C hybrid and examine its electrochemical performance for water oxidation. The hybrid catalyst displays a low overpotential of 420 mV to drive water oxidation at the current density of 200 mA cm−2, with a fast kinetics at the Tafel slope of 53.9 mV dec−1 and a low apparent activation energy of only 27.5 kJ mol−1. The catalyst also affords a better durability for OER compared to the commercial IrO2. The mechanistic analysis has revealed that the hybrid presents as the main form of amorphous organic-inorganic hybrid, in which the formation of high-valence metal species could serve as the highly active sites. The addition of carbon further reduces the resistance of electrochemical reaction. Based on these synergistical effects, the ternary FeCoMo/C catalyst facilitates the adsorption and reaction of oxygen-containing species, and thus promotes the proceeding of OER.