In-situ generated metallic Bi accelerating Z-scheme charge transfer in Bi2O3/Bi/PCN heterojunction for highly efficient photocatalytic NO oxidation

Artificial Z-scheme photocatalytic systems, inspired by natural photosynthesis, have been widely employed for pollutant removal. In this study, we fabricated a ternary Z-scheme Bi 2 O 3 /Bi/porous carbon nitride (PCN) heterojunction with an intimately coupled interface through a simple EG-assisted solvothermal approach to improving photocatalytic performance of NO oxidation. The in-situ generated metallic Bi acts as an electron mediator, effectively accelerating the separation and transfer of photoexcited carriers. The unique Z-scheme charge transfer mechanism provides the strong redox abilities and isolates the active sites for specific reactions, thus promoting photocatalytic NO oxidation activity. As a result, the optimized Bi 2 O 3 /Bi/PCN sample achieved a NO removal efficiency of 94.6%, outperforming single-component catalysts and most previously reported heterojunction-based photocatalysts. Additionally, in-situ Fourier transform infrared spectroscopy was employed to propose the NO removal mechanism, offering valuable insight into the conversion pathway. Such a heterogeneous Z-scheme photocatalytic system with a strong redox ability, high charge-separation efficiency, and long-term stability, demonstrates significantly enhanced photoactivity for pollutant removal and is expected to attract increasing interest for other photocatalytic applications.