Constructing an ohmic junction of copper@ cuprous oxide nanocomposite with plasmonic enhancement for photocatalysis

A novel ohmic junction Cu@Cu₂O photocatalyst with plasmonic enhancement had been successfully obtained by NaBH₄ reduction, which exhibited excellent photocatalytic performance for the catalytic oxidation of nitric oxide (NO) and catalytic reduction of carbon dioxide (CO₂). The desirable photocatalytic performance can be ascribed to the efficient interfacial charge separation and the high light absorption capacity induced by localized surface plasmon resonance (LSPR) of Cu nanoparticles in the Cu@Cu₂O photocatalyst. To better understand why this catalyst has satisfying stability and photocatalytic performance for the removal of NO and photocatalytic reduction of CO₂, a series of characterization methods was used to investigate the physical composition, structure, and optical properties of the sample in detail. Then, the separation efficiency of photogenerated carriers of the catalyst was investigated by time-resolved photoluminescence spectra, electrochemical impedance spectroscopy, and photocurrent density. In addition, Finite-Different-Time-Domain (FDTD) simulation and Cambridge Serial Total Energy Package (CASTEP) were adopted to confirm the Cu-induced LSPR effect, the electric field enhancement, and the band structure of the catalyst, respectively. Moreover, the ohmic junction structure has been verified by the calculation results of work function and charge density difference. Finally, a reasonable plasmonic ohmic junction photocatalytic mechanism was proposed and verified by the simulation and experiments.