Oxygen vacancy enhanced photocatalytic activity of CuO/TiO heterojunction.

In this study, a method was developed to create oxygen vacancies in CuO/TiO heterojunctions. By varying the amounts of ethylenediaminetetraacetic acid (EDTA), sodium citrate, and copper acetate, CuO/TiO with different Cu ratios were synthesized. Tests on CO photocatalytic reduction revealed that CuO/TiO's performance is influenced by Cu content. The ideal Cu mass fraction in CuO/TiO, determined by inductively coupled plasma (ICP), is between 0.075% and 0.55%, with the highest CO yield being 10.22 μmol g h, significantly surpassing pure TiO. High-resolution transmission electron microscopy and electron paramagnetic resonance studies showed optimal oxygen vacancy in the most effective heterojunction. Density functional theory (DFT) calculations indicated a 0.088 eV lower energy barrier for ∗CO to ∗COOH conversion in CuO/TiO with oxygen vacancy compared to TiO, suggesting that oxygen vacancies enhance photocatalytic activity.