Rapid Acidic Media Growth of Cs₃Bi₂Br₉ Halide Perovskite Platelets for Photocatalytic Toluene Oxidation

Abstract

Organic ligands with long carbon chains have been widely utilized to mediate the growth of halide perovskite crystals with tunable morphologies. However, the presence of these surfactants on the surface of halide perovskites limits their performance in photocatalytic conversion applications. Herein, a rapid synthetic protocol to prepare Cs3Bi2Br9 platelets with clean surfaces and controllable thickness in a dilute H2SO4 solution after a quick cooling process in liquid nitrogen or mixtures of dry ice is reported. Electron microscopy and X‐ray diffraction reveal the preferential exposure of (00l) facets in Cs3Bi2Br9 platelets with variable thickness from 100 to 500 nm. Infrared spectroscopy hints that the selective chemisorption of ethyl acetoacetate on (00l) facets of bismuth perovskites regulates the growth of the crystals. These novel lead‐free halide perovskite platelets can drive the photo‐oxidation of toluene to benzaldehyde with high selectivity (≥88%) and stability over 36 h.

Growth and Optical Properties of Lead‐Free Cs3Bi2Br9 Perovskite Microplatelets

“…The restriction of crystal growth by a strong surface interaction between the halide perovskites and the capping agent is the key to modify the morphologies of the micro-crystals. [28][29][30] For the growth of Cs 3 Bi 2 Br 9 MPs, bismuth atoms on the crystal surface serve as Lewis acid sites, [28] thus, EA was used as the capping agent to direct the growth of Cs 3 Bi 2 Br 9 . The selective interaction between bismuth atoms and two carbonyl groups of the EA leads to formation of regular shape of Cs 3 Bi 2 Br 9 in an acidic solution.…”

Enhanced Selective Photooxidation of Toluene to Benzaldehyde over Co3O4‐Modified BiOBr/AgBr S‐Scheme Heterojunction

“…[43][44][45] Herein, a ternary nanostructure of Co 3 O 4 /BiOBr/AgBr was fabricated through an in situ growth process together with a DOI: 10.1002/solr.202200279 Herein, photocatalytic selective oxidation of hydrocarbons through O 2 represents a promising way for fine chemical industry on account of its mild reaction condition. In this work, Co 3 O 4 -modified BiOBr/AgBr S-scheme heterojunction can effectively oxidize sp 3 C─H bonds at benzylic position to its corresponding aldehydes, with a toluene to benzaldehyde selectivity of 94%, which is much higher than that of pure BiOBr (21.7%) and AgBr (58.9%). A unique S-scheme charge-transfer mode is confirmed for the ternary composites by the X-ray photoelectron spectroscopy and reactive species quenching measurement.…”

“…Selective oxidation of C(sp 3 )─H bonds in aromatic alkanes into value-added chemicals (aldehydes, ketones, epoxides, etc.) is of vital importance for organic synthesis and transformation among the field of manufacturing industry.…”

“…is of vital importance for organic synthesis and transformation among the field of manufacturing industry. [1][2][3] However, because of the strong bond dissociation energy of sp 3 C─H in toluene (85.5 kcal mol À1 ), [4] the thermal activation and oxidation of C─H process is tough and energy consuming. [5][6][7][8][9] In a typical thermal catalytic procedure, harsh conditions, including high temperature and pressure, as well as the addition of toxic and aggressive oxidation reagents, are required, thus causing poor product selectivity.…”

“…The remaining photogenerated electrons in AgBr with powerful reduction ability can react with O 2 to generate •O 2 À species, which can further oxidize the benzyl radical formed on the Co 3 O 4 surface to peroxyl radicals and then thermodynamically decompose to benzaldehyde. Herein, this work has important guiding significance for the structure regulation of photocatalysts and application in selective oxidation of sp 3 C─H bond of hydrocarbons.…”