Engineering cuboctahedral N-doped C-coated p-CuO/n-TiO₂ heterojunctions toward high-performance photocatalytic...

The low separation efficiency of photogenerated electron-hole (e-h) pairs severely limits the activation of photocatalyts. One brilliant strategy is to construct a p-n type semiconductor heterojunction, which can establish an inner electric field to separate the e-h pairs with high efficiency. Here, for the first time, a cuboctahedral N-doped carbon-coated CuO/TiO₂ p-n heterojunction (CuO-TiO₂@N-C) was designed and fabricated successfully via direct calcination of a benzimidazole-modulated cuboctahedral HKUST-Cu with titanium-tetraisopropanolate absorbed inside concomitantly. Full structural characterizations incorporating DFT computations demonstrate that the CuO/TiO₂ p-n heterostructure can greatly boost the transport and separation of photoinduced e-h pairs. The nitrogen-doped carbon coating, with its excellent conductivity, porosity, stability and surface reaction activity, plays a pivotal role in promoting the overall performance and effectiveness of the reaction. The CuO-TiO₂@N-C displays significantly higher photocurrent density (0.042 μA cm^-2) than the CuO@N-C (0.014 μA cm^-2) and TiO₂@N-C (0.03 μA cm^-2) electrodes, proving that the p-n heterojunction can improve the e-h generation efficiency. This unique photocatalyst affords superior photocatalytic efficiency, cycle stability and substrate scope towards cross-dehydrogenative coupling reactions.