Designing S-scheme heterojunction via in situ converting partial NH2-MIL-68 into defective In2O3 for photocatalytic CO2 reduction

Via in situ converting partial NH 2 -MIL-68 into defective In 2 O 3, S-scheme heterojunction (In 2 O 3 @In-MOF) with oxygen vacancies (OVs) was easily constructed, which not only enhance the separation efficiency of photogenerated charge carriers of In-MOF, but also maintains the high reduction power of its photogenerated electrons as well as expanding its light absorption capacity, leading to higher photocatalytic CO 2 reduction activity. • S-scheme heterojunction (In 2 O 3 @In-MOF) is constructed via in situ converting partial In-MOF. • The in-situ derivatization strategy ensure the high-quality interface connection. • The S-scheme heterojunction enhances the separation efficiency of photogenerated charge carriers. • The S-scheme heterojunction maintains the high reduction power of photogenerated electrons. • In 2 O 3 @In-MOF exhibits enhanced catalytic activity than those of In-MOF and In 2 O 3 . Intrinsic characteristics of metal–organic frameworks (MOFs) make them become promising candidates for the application of photocatalytic CO 2 reduction. However, their photocatalytic activities are still unsatisfactory due to serious recombination of photogenerated charge carriers and insufficient light absorption. S-scheme heterojunction has demonstrated high superiority in the separation of charge carriers due to its unique structure and interface interaction. Nevertheless, it is difficult to construct it in MOF-based photocatalysts because of high interface connection requirements. Herein, a NH 2 -MIL-68 (In-MOF) is chosen as the research object. S-scheme heterojunction (In 2 O 3 @In-MOF) with oxygen vacancies (OVs) is easily constructed via in situ converting partial In-MOF into defective In 2 O 3 . The in-situ derivatization strategy is similar to epitaxial crystal growth, which could avoid drastic changes in the morphology of epitaxial growth rh-In 2 O 3 to ensure the high-quality interface connection. The S-scheme heterojunction not only enhances the separation efficiency of photogenerated charge carriers of In-MOF, but also maintains the high reduction power of its photogenerated electrons as well as expanding its light absorption capacity. Therefore, In 2 O 3 @In-MOF exhibits enhanced photocatalytic CO 2 reduction activity compared to those of pure In-MOF and In 2 O 3 . This work may open a potential pathway for the S-scheme heterojunction designing in the field of photocatalytic CO 2 reduction.