Solar-Driven Metal Halide Perovskite Photocatalysis: Design, Stability, and Performance

The development of green, sustainable, and economical chemical processes represents a cornerstone challenge within chemistry today. Semiconductor heterogeneous photocatalysis is currently utilized within a wide variety of societally impactful processes, spanning reactions such as hydrogen production and CO2 conversion, to the organic transformation of raw materials for value-added chemicals. Metal halide perovskites (MHPs) have recently emerged as a new promising class of cheap and easy to make photocatalytic semiconductors, though their unstable ionically bound crystal structure has thus far restricted widespread application. In this Review, we examine the issues hampering MHP-based photocatalysis and highlight the general approaches being taken to achieve promising and stable photocatalytic reaction environments. Specifically, we outline the adoption of (1) halogen acid solutions (i.e., HX; X = I or Br) for hydrogen evolution reactions, (2) relatively low-polarity solvents for CO2 photoreduction and organic transformations, and (3) the encapsulation of perovskites for CO2 reduction and water splitting. Further, we detail the measures being taken to arrive at intrinsically stable photocatalytic materials, removing the need for atypical environments. With each technology offering unique sets of benefits and challenges, we conclude by outlining potentially promising opportunities and directions for metal halide perovskite-based photocatalysis research moving forward.