Lead-Free Perovskite Cs₂ SnBr₆ /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 Cs₂ SnBr₆ decorated with reduced graphene oxide (rGO), is synthesized and employed in the photocatalytic organic conversion. The as-prepared Cs₂ SnBr₆ is ultrastable, exhibiting no clear changes after being placed in the air for six months. The Cs₂ SnBr₆ /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 ¹ O₂ 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.