A Supported Bismuth Halide Perovskite Photocatalyst for Selective Aliphatic and Aromatic C–H Bond Activation

Abstract

Direct selective oxidation of hydrocarbons to oxygenates by O2 is challenging. Catalysts are limited by the low activity and narrow application scope, and the main focus is on active C−H bonds at benzylic positions. In this work, stable, lead‐free, Cs3Bi2Br9 halide perovskites are integrated within the pore channels of mesoporous SBA‐15 silica and demonstrate their photocatalytic potentials for C−H bond activation. The composite photocatalysts can effectively oxidize hydrocarbons (C5 to C16 including aromatic and aliphatic alkanes) with a conversion rate up to 32900 μmol gcat−1 h−1 and excellent selectivity (>99 %) towards aldehydes and ketones under visible‐light irradiation. Isotopic labeling, in situ spectroscopic studies, and DFT calculations reveal that well‐dispersed small perovskite nanoparticles (2–5 nm) possess enhanced electron–hole separation and a close contact with hydrocarbons that facilitates C(sp3)−H bond activation by photoinduced charges.

Well‐Defined, Molecular Bismuth Compounds: Catalysts in Photochemically Induced Radical Dehydrocoupling Reactions

“…Indeed, a range of inorganic bismuth compounds such as (nanostructured) oxides (Bi 2 O 3 ), [8] titanates (Bi 4 Ti 3 O 12 ), [9] vanadates (BiVO 4 ), [10] halide perovskites (Cs 3 Bi 2 Br 9 ), [11] and an oxybromide (Bi 24 O 31 Br 10 (OH) δ ) [12] have been exploited in photocatalytic transformations. Catalysed types of reactions include the degradation of organic dyes such as methyl orange, [9] antibiotics such as tetracycline, [10] and biocides such as triclosan, [8b] as well as CH activation of aliphatic and aromatic hydrocarbons, [11] transfer (de)hydrogenation of alcohols/ketones, [12] and olefin polymerisation [8a] . These applications of bismuth compounds in heterogeneous catalysis suggest that photochemical strategies might also be applicable for well‐defined, molecular bismuth compounds under homogeneous conditions.…”

Photoredox Organic Synthesis Employing Heterogeneous Photocatalysts with Emphasis on Halide Perovskite

“…Selective CÀHb ondoxidation catalyzedbyu sing supported bismuthhalide perovskite photocatalysts. [102] Entry . [103] They demonstrated that combining the merits of photovoltaics in the photocatalyst architecture improvest he overall performance of such as ystem.…”

“…Owing to the heterogeneous nature of the catalysis, the conversion rate might be still of great synthetic significance, unlike the traditional homogeneous reactions, if the separation of product from the reactant can be resolved. In their most recent publication, the Tüysüz group reported that the hybrid halide perovskite discussed previously can also be used for the selective oxidation of both long‐chain hydrocarbons and certain aromatic compounds to produce both aldehydes and ketones. They are able to accomplish such transformations by impregnating the aforementioned Cs 3 Bi 2 Br 9 nanoparticles within the pores of mesoporous SBA‐15 silica.…”

Recent Progress in Engineering Metal Halide Perovskites for Efficient Visible‐Light‐Driven Photocatalysis

“…Recently, Tüysüz et al. demonstrated lead‐free Cs 3 Bi 2 Br 9 NCs (2–5 nm) confined in SBA‐15 (Cs 3 Bi 2 Br 9 ‐SBA‐15; Figure f) for the photocatalytic oxidation of C(sp 3 )−H bonds in hydrocarbons to their corresponding oxygenates . Under light irradiation, the electrons reduce the electron acceptors and holes from the VB (VBM, +2.17 eV vs. SHE) to promote the oxidation of C(sp 3 )−H bonds to form an alkyl radical, R .…”