Lead‐Free Perovskite Cs2SnBr6/rGO Composite for Photocatalytic Selective Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Diformylfuran.

Severe poisonousness and prolonged instability existing in organic‐inorganic lead‐based perovskite are two matters seriously hindering its potential future application in photocatalysis. Therefore, it is particularly important to explore ecology‐friendly, air‐stable and highly active metal‐halide perovskites. Herein, a new and stable lead‐free perovskite Cs2SnBr6 decorated with reduced graphene oxide (rGO), is synthesized and employed in the photocatalytic organic conversion. The as‐prepared Cs2SnBr6 is ultrastable, exhibiting no clear changes after being placed in the air for six months. The Cs2SnBr6/rGO composite shows excellent photocatalytic activity in photo‐driven‐oxidation of 5‐hydroxymethylfurfural (HMF) to high value enclosed 2,5‐diformylfuran (DFF), achieving>99.5 % conversion of HMF and 88 % DFF selectivity in the presence of green oxidant O2. Comprehensive characterizations disclose a multistep reaction mechanism, demonstrating that the molecular oxygen, photogenerated carriers, ⋅O2− and 1O2 altogether synergistically participate in the effective photo‐driven conversion of HMF to DFF. This work expands the material gallery towards selective organic conversion and environmentally friendly perovskite options for photocatalytic application. [ABSTRACT FROM AUTHOR]