Lewis acid-base interaction-reinforced MIL-101(Cr)@SnIn4S8 S‑scheme heterojunction for efficient gas-solid CO2 photoreduction

Interfacial engineering in heterostructure photocatalysts is crucial for efficient charge migration, yet achieving rational and controllable interface design remains a major challenge. In this work, SnIn 4 S 8 nanosheets were in situ grown on the octahedral surface of MIL-101(Cr) to leverage the Lewis acid-base properties of Cr and S, thereby enabling the controlled construction of an ion-coordinated interface. The resulting MIL-101(Cr)@SnIn 4 S 8 heterojunction enabled efficient capture and conversion of CO 2 and H 2 O. Furthermore, the Lewis acid-base coordination induces interfacial electron density redistribution, generating a built-in electric field that drives the formation of an S-scheme heterojunction between MIL-101(Cr) and SnIn 4 S 8 , while simultaneously preserving high‑energy photogenerated electron-hole pairs. Consequently, MIL-101(Cr)@SnIn 4 S 8 exhibited superior CO 2 photoreduction performance with H 2 O in the gas-solid phase, delivering a CO evolution rate of 26.9 μmol·g −1 ·h −1 . This work provides a viable strategy for interfacial engineering and demonstrates the application potential of S-scheme heterojunctions in photocatalytic reactions.