S-scheme heterojunction-mediated hydrogen production over the graphitic carbon nitride-anchored nickel stannate perovskite

A novel heterojunction between Sn-based perovskite and graphitic carbon nitride (gCN) is synthesized to achieve an enhanced spatial charge separation. The interfacial coupling between cube-shaped nickel tin oxide (NSO) and gCN is achieved through the surface sites in NSO. An improved hydrogen production rate of 646 µmol g⁻¹ h⁻¹ is measured in the composite (NSO-gCN), which is twice that in gCN, using triethanolamine (TEOA) and chloroplatinic acid (1% w/w) as holes scavenger and the precursor for the Pt cocatalyst, respectively. Such significant improvement in H₂ production performance of the composite is benefited by the high reductive electrons generated via an S-scheme charge transfer pathway, as evidenced by radical trapping experiments and XPS elemental analysis. The composite shows good stability in hydrogen evolution, with marginal (3%) decrease measured in the materials activity after 5 cycles. This study provides an opportunity to develop an S-scheme heterojunction with the Sn-based perovskite anchored in gCN, as an alternative to Ti-based perovskite for various photocatalytic reactions.