关键词: S型异质结, 硫化镉, 二氧化锰, 光热协同催化, 甲苯氧化

Abstract:

The targeted partial oxidation of toluene to valuable products continues to present a significant hurdle in catalytic science. To address the low efficiency of conventional photocatalysis, we developed a photothermal synergistic strategy by constructing a novel S-scheme CdS/MnO₂ heterojunction catalyst. CdS nanoparticles were anchored onto MnO₂, a material with intrinsic photothermal activity, forming a compact S-scheme heterojunction. This architecture generates an intrinsic electric field that markedly accelerates the segregation of light-induced charge carriers and inhibits their recombination. Moreover, CdS incorporation modulates the electronic band structure of MnO₂, thereby improving product selectivity. Owing to these synergistic effects, the optimized 25% CdS/MnO₂ catalyst demonstrated excellent catalytic performance, attaining a toluene oxidation rate of 14.1 mmol g⁻¹ h⁻¹ with an impressive 90% selectivity toward benzyl alcohol and benzaldehyde under an oxygen atmosphere at 150 ℃. Mechanistic investigations via Electron Paramagnetic Resonance and Fourier Transform Infrared Spectroscopy analyses revealed the pivotal role of photothermal synergy in promoting the oxidation process. This work not only provides an effective strategy for designing advanced photothermal heterojunctions but also presents new insights into the selective oxidation of toluene under mild conditions.

Key words: S-scheme heterojunction, CdS, MnO₂, Photothermal synergistic catalysis, Toluene oxidation