Synergistic effects of Fe-substitutional-doping and a surface close-contact Fe 2 O 3 /CeO 2 heterojunction in Fe/CeO 2 for enhanced CH 4 photocatalytic conversion

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2023-05, Vol.11 (21), p.11364-11376
• Main Authors: Tang, Hailong, Wang, Meiling, Ma, Yongqing, Sun, Xiao, Wang, Min, Zheng, Ganhong
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/D3TA00720K

The cleavage of the first C–H bond is a great challenge in achieving CH 4 conversion. Herein, we designed Fe/CeO 2 composite catalysts with efforts to reduce the activation energy of the C–H bond and improve CH 4 conversion. Both X-ray diffraction spectra and high-resolution transmission electron microscopy images confirmed the coexistence of an Fe/CeO 2 solid-solution phase and the surface close-contact Fe 2 O 3 /CeO 2 heterostructure. Density functional theory calculations validate distinct charge accumulations on the substitutional-doped Fe sites, which effectively lowered the reaction energy of CH 4 cleavage to form *CH 3 through induced CH 4 asymmetric polarization. Moreover, the existed surface close-contact Fe 2 O 3 /CeO 2 heterojunction effectively, which was comprehensively studied by using the band structure and in situ X-ray photoelectron spectra, improved carrier separation efficiency and further improved photocatalytic performance. In situ Fourier transform infrared spectra indicated the steady stream of CH 4 adsorption and quick dissociation on the catalyst surface. For the optimized sample, a high C1 product yield of 10.56 mmol g cat. −1 h −1 was achieved with the presence of H 2 O 2 , outperforming almost all previous reports as we know. This work elaborates the different roles of varied Fe sites in Fe/CeO 2 during the photocatalytic conversion of CH 4 , which has guiding significance for the development direction of composite catalysts in the future.