Synergistic interface and oxygen/nitrogen vacancy engineering in g-CN/CuO under high pressure for efficient CO photoreduction.

This study explores highly active nitride-based g-CN/CuO photocatalysts for CO photoconversion by synthesizing them through high-pressure torsion (HPT) straining. Data indicate that increasing the applied strain under high pressure promotes vacancy formation and improves the electronic interaction at the g-CN/CuO interphases, enabling superior charge separation and extended light absorption. The generation of dual vacancies of oxygen and nitrogen is verified by electron paramagnetic resonance and Fourier transform infrared spectroscopic methods, and the generation of a type-II heterojunction is confirmed by band structure analysis. Photocatalytic experiments reveal a threefold increase in the formation of CO and CH using g-CN/CuO in comparison with the pure g-CN photocatalyst. This investigation highlights the potential of synergic vacancy and interface engineering, realized by HPT for the first time in nitride-based composites, for sustainable CO photoreduction applications.