Stable MAPbBr3@PbBr(OH) composites with high photoluminescence quantum yield: Synthesis, optical properties, formation mechanism, and catalytic application

•MAPbBr3@PbBr(OH) fabrication was designed without the risk of decomposing perovskites.•MOF-triggered transformation of PbBr(OH) occurs simultaneously with MAPbBr3 formation.•MAPbBr3@PbBr(OH) showed high PLQY of 74.4–90.6% and outstanding solvent stability.•Composite could be employed as photocatalysts for organic dye degradation in water.