Improving the stability of lead halide perovskite quantum dots (QDs) in a system containing water is the key for their practical application in artificial photosynthesis. Herein, we encapsulate low‐cost CH3NH3PbI3 (MAPbI3) perovskite QDs in the pores of earth‐abundant Fe‐porphyrin based metal organic framework (MOF) PCN‐221(Fex) by a sequential deposition route, to construct a series of composite photocatalysts of MAPbI3@PCN‐221(Fex) (x=0–1). Protected by the MOF the composite photocatalysts exhibit much improved stability in reaction systems containing water. The close contact of QDs to the Fe catalytic site in the MOF, allows the photogenerated electrons in the QDs to transfer rapidly the Fe catalytic sites to enhance the photocatalytic activity for CO2 reduction. Using water as an electron source, MAPbI3@PCN‐221(Fe0.2) exhibits a record‐high total yield of 1559 μmol g−1 for photocatalytic CO2 reduction to CO (34 %) and CH4 (66 %), 38 times higher than that of PCN‐221(Fe0.2) in the absence of perovskite QDs.

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The field of nanozymes has developed rapidly over the past decade. Among various oxidoreductases mimics, catalase (CAT)‐like nanozyme, acting as an essential part of the regulation of reactive oxygen species (ROS), has attracted extensive research interest in recent years. However, CAT‐like nanozymes are not as well discussed as other nanozymes such as peroxidase (POD)‐like nanozymes, etc. Compared with natural catalase or artificial CAT enzymes, CAT‐like nanozymes have unique properties of low cost, size‐dependent properties, high catalytic activity and stability, and easy surface modification, etc., which make them widely used in various fields, especially in tumor therapy and disease treatment. Consequently, there is a great requirement to make a systematic discussion on CAT‐like nanozymes. In this review, some key aspects of CAT‐like nanozymes are deeply summarized as: 1) Typical CAT‐like nanozymes classified by different nanomaterials; 2) The catalytic mechanisms proposed by experimental and theoretical studies; 3) Extensive applications in regard to tumor therapy, cytoprotection and sensing. Therefore, it is prospected that this review will contribute to the further design of CAT‐like nanozymes and optimize their applications with much higher efficiency than before.

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