The Sb-N charge transfer bridge over Cs3Sb2Br9/Sb-C3N4 Z-scheme heterojunction for boosting photocatalytic CO2 reduction

Developing highly efficient heterostructural photocatalysts for direct CO2 reduction coupled with water oxidation remains challenging, the key to which is to establish an efficient interfacial charge transport channel. Herein, we present a Cs3Sb2Br9/Sb-C3N4 Z-scheme heterojunction prepared with an in-situ growth method based on the Sb atomic pinning effect. As revealed by the analysis of experimental and theoretical calculation results, the introduction of Sb anchors on C3N4 leads to the formation of an Sb-N charge transfer bridge between Cs3Sb2Br9 and C3N4, promoting interfacial charge communication over Cs3Sb2Br9/Sb-C3N4 heterojunction. Moreover, it can induce the heterojunction interfacial charge transfer pathway between Cs3Sb2Br9 and C3N4 to change from type II to the type Z-scheme, enabling the change of the catalytic site from C3N4 to Cs3Sb2Br9, thus promoting the CO2 activation. As a result, Cs3Sb2Br9/Sb-C3N4 achieves efficient CO2 to CO photocatalytic conversion using water as the electron source under simulated solar light irradiation (100 mW<middle dot>cm(-2)), with the yield of 198.4 mu mol<middle dot>g(-1)<middle dot>h(-1), which is nearly 3-fold and 9-fold over the counterpart synthesized catalyst without Sb anchors (Cs3Sb2Br9/g-C3N4) and pure g-C3N4, respectively. This work provides a new alternative solution for the design of highly efficient heterojunction photocatalysts.