Metal halide perovskite photocatalysts: recent progress, challenges, and future directions

Metal halide perovskite photocatalysts (MHPPs) exhibit unique electronic and optical properties, making them attractive for diverse photocatalytic applications. Their exceptional properties can be tuned by adjusting the halide ion or cation size. MHPPs have shown promise in solar energy conversion, water splitting, and air purification. However, synthesis and stability challenges hinder practical applications. This comprehensive review presents the properties, applications, and challenges of MHPPs, proposing future research directions. Although dogged by many issues, MHPPs demonstrate remarkable charge separation capabilities, rendering them advantageous in many photocatalytic applications. They offer flexibility through the manipulation of elements, crystal structures, surface chemistry, and morphologies. The review also discusses Type-II, Z-scheme heterojunction, as well as the emerging S-scheme heterojunction, which is a recent, improved alternative. Consolidating current knowledge, this review serves as a valuable resource, providing insights into MHPPs' potential and guiding further advancements. MHPPs have significant applications in water splitting, air purification, pollutant degradation, and energy conversion. Their unique properties and versatility enable tailored optimization. This overview is a crucial reference for researchers, engineers, scholars, and students, inspiring innovative and sustainable photocatalytic solutions.