Cu²⁺-Guided Construction of the Amorphous CoMoO₃/Cu Nanocomposite for Highly Efficient Water Electrolysis

Designing highly efficient and durable electrocatalysts for overall water splitting is of great importance for the sustainable generation of high purity hydrogen. Herein, an amorphous CoMoO3/Cu (a-CoMoO3/Cu) electrode was designed and fabricated through a facile Cu2+-guided electrodeposition strategy. During the synthetic process, the formation of the Co3Mo alloy was suppressed, and the precipitation of a-CoMoO3 was accelerated due to the easily reduced feature of Cu2+. Moreover, metallic Cu can also endow the a-CoMoO3/Cu nanocomposite with remarkably high electron transfer rates. Benefitting from the synergetic effect between Cu and a-CoMoO3 and the high activity of a-CoMoO3, the as-prepared nanocomposite exhibits excellent water electrolysis performance with a low cell voltage of 1.50 V at 10 mA cm–2, which is superior to that of the Pt/C||Ir/C pair. Such prominent performance can be attributed to the abundance of active sites, as well as the optimal adsorption/desorption energy of the intermedia. DFT calculations demonstrate a-CoMoO3 as the real active site for hydrogen adsorption/desorption and the vital role of Cu in the enhanced water adsorption. The outstanding electrochemical activity and durability of the a-CoMoO3/Cu nanocomposite indicate its potential as a highly efficient water-splitting electrocatalyst.