Converting hydrocarbons into aldehydes in a green and environmentally benign way is of great significance in fine chemistry. In this work, all-inorganic Cs₃Bi₂Br₉ perovskite nanoparticles were uniformly loaded on BiOBr nanosheets via an in-situ growth method, which can selectivity photoactivate aromatic C(sp³)−H bond of toluene to generate benzaldehyde. According to the in-situ X-ray photoelectron spectroscopy characterization, the photogenerated electrons of BiOBr transfer to Cs₃Bi₂Br₉ enforced by the internal electric field under light irradiation, resulting in S-scheme heterojunction. Furthermore, theoretical calculations indicate that toluene molecules are inclined to adsorb on the BiOBr surface, subsequently involving the oxidation reaction to generate benzyl radical (PhCH₂•) by using the energetic holes of BiOBr, while the remaining photoinduced electrons in the conduction band (CB) of Cs₃Bi₂Br₉ with powerful reduction ability reduce O₂ into •O₂⁻, which is the vital oxidative active species working on toluene selective oxidation process. Such an unexceptionable charge carrier utilization mode and tendentious adsorption behavior of reactants contribute to the optimized Cs₃Bi₂Br₉/BiOBr heterojunction with excellent photocatalytic performance, achieving a maximum of 22.5% toluene conversion and 96.2% selectivity towards benzaldehyde formation. This work provides a rational photocatalyst heterojunction construction protocol for the selective oxidation of saturated aromatic C−H bonds.

以绿色和环境友好的方式将碳氢化合物转化为醛在精细化学中具有重要意义。在这项工作中，全无机Cs ₃ Bi ₂ Br ₉钙钛矿纳米粒子通过原位生长方法均匀负载在BiOBr纳米片上，可以选择性光活化甲苯的芳族C(sp ³ )−H键生成苯甲醛。根据原位X射线光电子能谱表征，BiOBr的光生电子转移到Cs ₃ Bi ₂ Br ₉在光照射下由内部电场强制执行，导致 S 型异质结。此外，理论计算表明，甲苯分子倾向于吸附在BiOBr表面，随后利用BiOBr的高能空穴进行氧化反应生成苄基自由基（PhCH ₂ •），而导带中剩余的光生电子（CB )的Cs ₃ Bi ₂ Br ₉具有强大的还原能力，可将O ₂还原为•O ₂ ⁻, 是参与甲苯选择性氧化过程的重要氧化活性物质。这种无可挑剔的载流子利用模式和反应物的倾向性吸附行为有助于优化 Cs ₃ Bi ₂ Br ₉ /BiOBr 异质结，使其具有出色的光催化性能，实现最高 22.5% 的甲苯转化率和 96.2% 的苯甲醛形成选择性。这项工作为饱和芳族 C-H 键的选择性氧化提供了一种合理的光催化剂异质结构建方案。