Hybridization of CuO with Bi₂MoO₆ Nanosheets as a Surface Multifunctional Photocatalyst for Toluene Oxidation under Solar Irradiation

Abstract

Herein, CuO/Bi₂MoO₆ hybrid nanosheets were prepared as a surface multifunctional photocatalyst for gas-phase toluene oxidation with high conversion (>99%). Aberration-corrected scanning transmission electron microscopy suggested that CuO species were highly dispersed on the nanosheets. X-ray absorption fine structure spectra indicated that the distorted and stretched Cu-O coordination structures in CuO/Bi₂MoO₆ nanosheets would provide open active sites. In situ Fourier transform infrared and density functional theory results showed that toluene molecules could be chemisorbed and activated on the active sites of CuO/Bi₂MoO₆ nanosheets by the C-H group forming CuO/Bi₂MoO₆···Ph-CH₃ surface complex compounds. These would induce electron-hole transfer and initiate photocatalytic reactions under visible light irradiation. The corresponding intermediates of benzaldehyde and benzoic acid would be detected by in situ diffuse reflectance infrared Fourier transform spectroscopy. Furthermore, the synergistic effect of CuO and Bi₂MoO₆ nanosheets could monitor charge dynamics to facilitate their respective transmission from photoexcitation sites to active centers. This work provides new insights into the essence of visible-light-driven surface photocatalysis and is expected to promote the design of novel and more effective photocatalysts at the molecular level.