The photocatalytic production of syngas from CO2 and water is an attractive and straightforward way for both solar energy storage and sustainable development. Here, we combined the hybrid shell of a bimetallic metal–organic framework (MOF) Zn/Co-zeolitic imidazolate framework (ZIF) and the hybrid photoactive center of Ni-doped CdS nanoparticles (Ni@CdS) to construct a new “2 + 2” photocatalysis system Ni@CdS⊂Zn/Co-ZIF through a facile self-assembly process, which exhibited a double-synergic effect for visible light harvesting and CO2 conversion, leading to one of the highest photocatalytic syngas production rates and excellent recyclability. The H2/CO of syngas ratios can be readily adjusted by controlling the ratio of Zn/Co in the hybrid MOF shell.

Metal−organic frameworks (MOFs) represent an ideal platform for the construction of highly active composite catalysts. However, loading metastable and/or multicomponent metal compounds into MOFs remains a synthetic bottleneck due to the great challenge of keeping the guest and matrix intact during the preparation of a composite. In this work, we develop a new impregnation reduction surface modification (IRSM) strategy to give a new composite catalyst CuCl@MIL-101(Cr), which is successfully postmodified by in situ construction of Cu II defects on the surface of loaded CuCl inside MOF pores, leading to the new composite material Cu II /Cu I @MIL-101(Cr). The new dual-component composite catalyst exhibits a hierarchical structure and superior catalytic activity in C−C homocoupling of arylboronic acids under green conditions. This study presents a facile strategy for improving the catalytic activity by constructing defects on the surface of MOF-based catalysts as well as for forming multiple-component composite materials.