The Construction of p/n-Cu 2 O Heterojunction Catalysts for Efficient CO 2 Photoelectric Reduction.

Cu₂O is a p-type direct bandgap semiconductor with a band gap of 2~2.2 eV, which has excellent visible light absorption and utilization. However, slow charge transfer and poor stability hinder its practical application. In this paper, a facile electrodeposition approach successfully synthesized the heterostructure of p-Cu₂O and n-Cu₂O. The protective layer of n-Cu₂O on the surface of p-Cu₂O nanoparticles forms a p/n heterojunction. Due to the p/n heterojunction, the PEC performance of p/n-Cu₂O is enhanced significantly. The charge separation efficiency of photogenerated electron/hole pairs in p/n-Cu₂O is greatly improved. Therefore, p/n-Cu₂O shows superior photoelectrochemical (PEC) CO₂ reduction reaction (CO₂RR) efficiency when used as a photocathode. [ABSTRACT FROM AUTHOR]