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

Abstract

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.

Lattice dynamics and self-trapped excitons in the Cs2SnBr6 double perovskites

“…The Self-trapped state emission from the isolated [SnBr 6 ] 2− octahedra may be responsible for these features [27]. Yin et al [28] have presented a comprehensive analysis of a distinct visible emission band centered at 660 nm, attributed to the significant recombination of electrons and holes. That finding is pivotal as it reveals PL average lifetimes of 5.8 ns, a crucial factor in promoting the migration and separation of photogenerated charges [29].…”

Sunlight-driven photocatalytic conversion of furfural and its derivatives

“…In light of that, Yin et al synthesized a stable Pb-free chalcogenide Cs 2 SnBr 6 modified with reduced graphene oxide (rGO). 75 The Cs 2 SnBr 6 /rGO composite exhibited excellent photocatalytic activity. Almost full conversion of HMF and 88% selectivity of DFF were obtained in acetonitrile.…”

Photocatalysis Based on Metal Halide Perovskites for Organic Chemical Transformations

“…Wang and co-workers carried out a similar reaction by employing a Schottky heterojunction consisting of lead-free Cs 2 SnBr 6 (bandgap 2.86 eV) and reduced graphene oxide (rGO), as shown in Figure 43 b [ 171 ], using a 300 W Xe lamp with a 400 nm cut-off filter. The outcome was a selective conversion of HMF to DFF (>99.5%), while a selectivity of 88% for DFF was obtained when using Cs 2 SnBr 6 /rGO heterostructures ( Figure 43 c).…”