Frustrated Lewis Pairs on In(OH)3–x Facilitate Photocatalytic CO2 Reduction

Photocatalysis is promising for the reduction of CO 2 into fuels and chemicals under mild conditions but is still a challenge due to the inert nature of CO 2 . Herein, a ZnIn 2 S 4 /In(OH) 3– x (ZIOS) heterojunction was developed for visible-light-driven CO 2 reduction, where ZnIn 2 S 4 (ZIS) harvests the light and In(OH) 3– x with frustrated Lewis pairs (FLPs) activates the CO 2 . The hydroxyl-deficient vacancies (OH Vs ) of In(OH) 3– x act as a Lewis acid, and the adjacent hydroxyl groups serve as a Lewis base to form FLPs. The ZIOS composites are fabricated via partial sulfurization of Zn–In–O oxide, constructing a type II heterojunction that facilitates the photogenerated electron transfer from ZnIn 2 S 4 to reduce FLP-activated CO 2 on In(OH) 3– x . The as-prepared ZIOS composites exhibit a CO formation rate of 1945.5 μmol·g –1 ·h –1, which is about 2.76-fold higher than that over ZnIn 2 S 4, and suppress hydrogen evolution with the CO/H 2 ratio increasing from 0.436 for ZnIn 2 S 4 to 1.6 for ZIOS. This work provides insight into the design of efficient CO 2 reduction photocatalysts.