Amorphous Co-doped MoOx nanospheres with a core–shell structure toward an effective oxygen evolution reaction

Abstract

The development of effective non-noble metal based catalysts for the electrocatalytic oxygen evolution reaction (OER) at lower overpotentials has attracted tremendous attention due to its important role for various electrochemical energy storage and conversion devices. Transition metal based oxides have been deeply investigated, benefiting from their promising catalytic activity as well as their low cost. However, among these oxides, the OER efficiency of molybdenum oxides has rarely been studied due to its limited intrinsic activity. Herein, we reported amorphous cobalt-doped molybdenum oxide (Co–MoO_x) with a core–shell structure as an effective OER catalyst for the first time. Benefiting from the cobalt doping as well as the amorphous structural character, the charge transfer process and the active sites are both well optimized, which is highly desired for an advanced electrocatalyst. As expected, the Co–MoO_x catalyst afforded an extremely low overpotential of 340 mV at a current density of 10 mA cm⁻², and a small Tafel slope of 49 mV dec⁻¹ in KOH solution. This work shows an effective strategy for the realization of highly efficient OER electrocatalysts.