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 metalhalide 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 O-2. Comprehensive characterizations disclose a multistep reaction mechanism, demonstrating that the molecular oxygen, photogenerated carriers, center dot O-2(-) and O-1(2) 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.

Automated summary

Severe poisonousness and prolonged instability are major challenges for the future application of organic-inorganic lead-based perovskite in photocatalysis. In this study, a stable lead-free perovskite Cs2SnBr6 decorated with reduced graphene oxide (rGO) was successfully synthesized and applied in photocatalytic organic conversion. The Cs2SnBr6/rGO composite exhibited excellent photocatalytic activity for the photo-driven oxidation of 5-hydroxymethylfurfural (HMF) to high value enclosed 2,5-diformylfuran (DFF). The comprehensive characterizations revealed a multistep reaction mechanism involving molecular oxygen, photogenerated carriers, center dot O-2(-), and O-1(2). This work expands the material options for selective organic conversion and provides an environmentally friendly perovskite for photocatalytic applications.