Layered Perovskite/g-C3N4 S-Scheme Heterojunction for an Improved Photocatalytic Reduction of Bicarbonate to Formate

A Ruddlesden-Popper phase-layered perovskite Fe2SnO4 is coupled with graphitic carbon nitride (gCN) in an S-scheme heterojunction. The Fe2SnO4/gCN heterojunction is synthesized using the sonication-calcination method. The layered structure of Fe2SnO4 enhances charge migration toward the junction interface and enables the internal electric field, increasing the charge separation in the overall composite. The optical characteristics of Fe2SnO4/gCN show an excellent visible light utilization ability, thus expanding its applicability in solar (visible light)-driven catalytic approaches. A significant formate generation rate (2.043 mM h(-1) gcat(-1)) is measured over the photocatalyst using the aqueous bicarbonate as the CO2 precursor. The isotope labeling test corroborates the generation of formate from bicarbonate. Fe2SnO4/gCN also displays a good stability over five reaction-regeneration cycles. The band structure of Fe2SnO4/gCN in conjunction with the radicals detected via spin trapping confirms the development of the S-scheme heterojunction in Fe2SnO4/gCN. Herein, the fabrication of the layered perovskite-based S-scheme heterojunction paves a path for pursuing the solar-driven environmental remediation strategies.