Lead-free metal halide perovskites as the rising star in photocatalysis: The past, present, and prospective

Lead-based perovskite materials (LBPMs) have sparked tremendous research interest in photocatalysis applications; however, the commercialization of LBPM photocatalysts has been hampered due to structural instability and lead (Pb2+) ion toxicity. In this regard, it is vital to produce ecologically acceptable and highly stable perovskite photocatalysts. A complete substitution of Pb2+ was adopted to fabricate lead-free perovskite material quantum dots (LFPMs QDs) to tackle the challenge. We present an in-depth investigation for the scientific advancement of LFPMs in the photocatalysis application. Due to their suitable bandgap, greater light absorptivity efficiency, and green technology, LFPMs showed promising performance in various photocatalysis applications, including water splitting, CO2 reduction, pollutant degradation, and organic synthesis. The performance of LFPMs-based photocatalysts in the application above was comprehensively summarized. The formation of heterojunction nanocomposite using LFPMs and co-catalysts or hole-transporting materials could accelerate photogenerated electrons and holes while suppressing recombination rate, thereby boosting LFPMs photocatalytic performance, especially in CO2 reduction and water splitting reactions. Furthermore, the benefits and drawbacks of utilizing LFPMs photocatalysts were discussed in terms of performance, stability, and long-term utilization. The review concludes with an underlying discussion and proposed future research initiatives. LFPMs QDs might become the next generation photocatalyst by outshining concurrently used photocatalysts materials.