Ohmic contact Metal/ZnO heterostructure for CO 2 photoreduction to CO

Abstract Photocatalytic CO 2 reduction using solar energy offers a promising path to carbon neutrality, with ZnO as a favored semiconductor due to its abundance, favorable band alignment, and eco‐friendliness. However, challenges such as high carrier recombination, limited light absorption, and poor CO 2 adsorption limit its performance. To overcome these issues, an Ohmic contact heterostructure strategy is proposed. A theoretical screening of five noble metals (Ag, Pd, Ir, Au and Pt) for forming Ohmic contact metal–semiconductor heterostructures with ZnO was conducted, followed by experimental validation. Among these, the Au/ZnO heterostructure, with an appropriate Fermi level difference (Δ( Ф ZnO — Ф metal )) of 2.02 eV, achieved the highest CO yield of 28.66 μmol g –1 h −1 , significantly outperforming than other Metal/ZnO combinations. Further investigation of Au/ZnO revealed that the Ohmic contact enhances photogenerated carrier separation, while Au nanoparticles serve as active sites and promote key reactions, including CO 2 adsorption, *COOH formation, and *CO desorption, leading to improved CO 2 reduction efficiency. This work provides valuable insights into the design of high‐performance photocatalysts based on Ohmic contact heterostructures, offering potential solutions for energy and environmental challenges.