Anchoring CoO nanoparticles on MXene for efficient electrocatalytic oxygen evolution.

Rational design and controllable synthesis of efficient electrocatalysts for water oxidation is of significant importance for the development of promising energy conversion systems, in particular integrated photoelectrochemical water splitting devices. Cobalt oxide (CoO) nanostructures with mixed valences (II,III) have been regarded as promising electrocatalysts for the oxygen evolution reaction (OER). They are able to promote catalytic support of OER but with only modest activity. Here, we demonstrate that the OER performance of cubic CoO electrocatalyst is obviously improved when they are anchored on delaminated two-dimensional (2D) TiC MXene nanosheets. Upon activation the overpotential of the hybrid catalyst delivers 300 mV at a current density of 10 mA cm in basic solutions, which is remarkably lower than those of TiC MXene and CoO nanocubes. The strong interfacial electrostatic interactions between two components contribute to the exceptional catalytic performance and stability. The enhanced OER activity and facile synthesis make these CoO nanocubes-decorated ultrathin 2D TiC MXene nanosheets useful for constructing efficient and stable electrodes for high-performance electrochemical water splitting.