Dual active sites based CsPbBr3/porous carbon nitrides S-scheme heterojunction for synergetic vanillin and hydrogen peroxide production

Although CsPbBr₃ and carbon nitride heterojunctions show great promise in photocatalytic CO₂ reduction, their application in oxidation-driven reactions remains largely unexplored. Inspired by the strong photogenerated electron reduction capabilities and the favorable oxidation ability of the photogenerated holes at the interfaces between CsPbBr₃ and porous carbon nitride nanosheets (PCN), we construct an S-scheme heterojunction composed of CsPbBr₃ and PCN. This heterojunction system enables the simultaneous production of vanillin and hydrogen peroxide under visible-light irradiation. Utilizing the respective Pb and N active sites, the system achieves yields of 32.5 mM for vanillin and 10 mM for H₂O₂. The rationally designed S-scheme heterojunction enhances charge separation via the internal electric field while spatially allocating oxidation and reduction reactions on PCN and CsPbBr₃, improving selectivity and overall efficiency. Mechanism investigations indicate that the Pb and N sites play a significant role in facilitating photocatalytic activity. This work offers a promising strategy for integrating organic transformation and green oxidant production. Additionally, it provides valuable insights into designing multifunctional photocatalysts for sustainable chemical processes.