The solid-state in situ construction of Cu2O/CuO heterostructures with adjustable phase compositions to promote CO oxidation activity

Heterostructured Cu-based oxides have been widely used in many fields, such as energy storage, catalysis, and sensing. Conventional techniques for the synthesis of hybrid oxides are time-consuming and often result in low yields. The scalable preparation of heterostructured Cu-based oxides with adjustable phase composition remains a substantial challenge. We demonstrate a simple and efficient solid-state synthesis strategy for the in situ preparation of Cu2O/CuO heterostructured nanorods approximately 10 nm in width, without the use of solvents and post-calcining processing. Tuning the ratio of reactants enables optimization of the components of the Cu2O/CuO heterostructures and their catalytic activities for the carbon monoxide (CO) oxidation reaction. Benefiting from controllable composition, a synergistic effect, and surface-adsorbed oxygen, the resulting Cu2O/CuO heterostructures (Cu2O/CuO-5) show significantly improved catalytic performance in the CO oxidation reaction process. We provide a new and simple method for synthesizing various metal oxide heterostructures for wide-ranging applications.