Plasmon-promoted oxygen evolution catalysis with Ag nanocrystals loaded α-Co(OH)2 nanosheets

•A composite catalyst of α-Co(OH)2/Ag was obtained by a photochemical deposition route.•Loading of silver on α-Co(OH)2 can enhance the catalytic activity for oxygen evolution.•Low powder of laser irradiation can induce the decrease of catalytic overpotential.•The catalytic electrode after catalytic process was analyzed.•Laser irradiation motivates the formation of active cobalt sites and induces the activity enhancement.