Controllable in situ growth of amorphous MoSx nanosheets on CoAl layered double hydroxides for efficient oxygen evolution reaction

Abstract

The high demand for renewable energy storage and conversion has led to the exploration of highly efficient, low cost electrocatalysts for the oxygen evolution reaction (OER). Herein, CoAl layered double hydroxides (LDHs) hybridized with amorphous MoSx nanosheets (CoAl-MoSx-X, where X is the reduction reaction time) were synthesized in situ through a two-step procedure. Among these electrocatalysts, CoAl-MoSx-12 exhibited the highest OER performance with an overpotential of 330 mV at 10 mA cm−2 and a Tafel slope of 59 mV dec−1 in alkaline solution. The underlying mechanism revealed that the density and the thickness of the MoSx nanosheets on CoAl LDHs both play key roles in the enhanced OER activity by offering more exposed active sites and accelerated electron transfer. In addition, the in situ growth provides an intimate contact between MoSx and the CoAl LDHs which is responsible for the relatively long-lasting stability of the electrocatalyst. This strategy adds to the methods available for the synthesis of LDH-supported materials as electrocatalysts with enhanced activity for renewable energy storage and conversion. Keywords: Layered double hydroxides, Amorphous MoSx, In situ growth, Oxygen evolution reaction