Hierarchical nanostructure with ultrafine MoO3 particles-decorated Co(OH)2 nanosheet array on Ag nanowires for promoted hydrogen evolution reaction

It is an efficient and green way to obtain hydrogen with the assistance of highly active and low-cost electrocatalysts by using the electrochemical water electrolysis process in the alkaline electrolyte. Herein, MoO3 particles-decorated Co(OH)2 nanosheet array with a hierarchical nanostructure wrapped Ag nanowires (MoO3-Co(OH)2@Ag NWs) electrocatalysts have been constructed via a two-step electrodeposition method. Ag nanowires have functioned as a conductive network to improve electron transportation ability. As-prepared MoO3-Co(OH)2@Ag NWs catalysts show good HER performance compared with the original Co(OH)2 by delivering at a low overpotential of 220 mV at a current density of −100 mA cm−2, while those for pristine Co(OH)2 and MoO3 are 290 and 412 mV, respectively. The good durability performance of the MoO3-Co(OH)2@Ag NWs catalyst can last for 29 h at a high current density of 100 mA cm−2 with negligible loss, demonstrating the possible commercial application in electrochemical water splitting. A theoretical study has been carried out to understand the reaction kinetics in the generated heterostructure (MoO3-Co(OH)2), which can significantly promote hydrogen evolution reaction process with the reduced adsorption energy of water (ΔGH2O*) and decreased Gibbs free-energy of adsorbed H* (ΔGH*) during the hydrogen evolution reaction process. This work can help us to design high-active catalysts with the heterointerface-dependent mechanism for electro-catalytic water splitting processes.