Perovskite Nanocomposite: A Step Toward Photocatalytic Degradation of Organic Dyes

Metal halide perovskites offer a promising opportunity for transforming solar energy into chemical energy, thereby addressing pressing environmental challenges. While their excellent optoelectronic properties have been successfully applied in photovoltaics, their potential in photocatalysis remains relatively unexplored. Herein, we report a novel humidity‐driven approach for the in situ synthesis of MAPbI 3 nanocrystals (NCs) within a nickel acetate matrix, forming a nanocomposite thin film that enhances the system's stability and enables its use in photochemical reactions. UV‐Vis spectroscopy and X‐ray diffraction confirm the rapid and effective synthesis of NCs within the matrix after 1 min at 80% relative humidity (RH). Optimal photoconversion conditions are attained after 60 min of exposure at 80% RH, due to the increased porosity and nanocrystal size over time as revealed by electron microscopy. The MAPbI 3 ‐Ni(AcO) 2 nanocomposite exhibits superior photocatalytic activity compared to standard polycrystalline MAPbI 3 films for the decomposition of Sudan III under simulated sunlight. Furthermore, the nanocomposite demonstrates good recyclability over multiple cycles. Overall, this work highlights the potential of MHP‐based nanocomposites for solar‐driven catalytic systems in pollution mitigation.