Fe doped Mo/Te nanorods with improved stability for oxygen evolution reaction

Abstract

The high valence state of Mo is active but unstable for the water oxidation reaction. Herein, we proposed that taking a core–shell structure of Mo/Te as an example, its stability can be largely improved by the facile Fe-doping approach. A performance decay of 70% at 1.65 V was observed in the initial 20 cycles for the Mo/Te alone resulting from the high activity but unstable active Mo species, while very stable catalytic ability was found on the Fe doped Mo/Te catalyst in terms of the initial activation process, dynamic and steady-state stability. The Fe-doped Mo/Te catalyst required an overpotential of ca. 300 mV to reach the benchmark current density of 10 mA cm−2 when drop-casting on the glass carbon electrode. A Tafel slope of 45.6 mV dec-1 and the Faraday efficiency close to 100% were demonstrated on this electrode. As revealed by the spectroscopic analysis and the electrochemical kinetics measurement, the improved activity and stability could be attributed to the Fe-doped Mo/Te structure that has increased electrochemical surface area, the high valence state of Mo species formation, faster catalytic kinetics, rapid charge transfer ability as well as the strong electronic state modification. The current study reveals an effective approach to stabilizing the active Mo-based catalysts for OER via the synergistic effect of Fe and Mo.