Heterojunction of Metal Plasmas and CoO Nanofilms for Ultraefficient Activity to Oxygen Evolution Electrocatalysts

Hydrogen production by electrolysis of water is expected to be one of the important technologies for sustainable clean energy production, but the sluggish kinetics of the oxygen evolution reaction (OER) hampers commercialization. The atomic layer deposition and high-energy metal plasma implantation were used to construct heterostructures of CoO with different thicknesses and multiple metals. Among them, the heterostructure constructed by cobalt oxide and Zr metal shows better oxygen evolution catalytic activity than other Ag, Ti, and Cr metals. With the increase of the number of Zr atoms and the thickness of the cobalt oxide layer, the OER activity first increased and then gradually decreased. The Zr500/12CoO metal–semiconductor heterojunction has a larger barrier height and more electron–hole pairs, which makes the metal surface more positively charged and promotes the adsorption of OH–. Construction of metal–semiconductor heterojunctions provides insights into the design and surface–interface modification of efficient, low-cost, and durable electrodes for water splitting applications.