Selective CH4 Partial Photooxidation by Positively Charged Metal Clusters Anchored on Carbon Aerogel under Mild Conditions

Kai Zheng; Yang Wu; Zexun Hu; Xingchen Jiao; Li Li; Yuan Zhao; Shumin Wang; Shan Zhu; Wenxiu Liu; Wensheng Yan; Yongfu Sun; Yi Xie

doi:10.1021/acs.nanolett.1c03682

Selective CH₄ Partial Photooxidation by Positively Charged Metal Clusters Anchored on Carbon Aerogel under Mild Conditions

Nano Lett. 2021 Dec 22;21(24):10368-10376. doi: 10.1021/acs.nanolett.1c03682. Epub 2021 Dec 13.

Authors

Kai Zheng¹, Yang Wu¹, Zexun Hu¹, Xingchen Jiao¹, Li Li¹, Yuan Zhao¹, Shumin Wang¹, Shan Zhu¹, Wenxiu Liu¹, Wensheng Yan¹, Yongfu Sun^{1

2}, Yi Xie^{1

2}

Affiliations

¹ Hefei National Laboratory for Physical Sciences at Microscale, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, People's Republic of China.
² Institute of Energy, Hefei Comprehensive National Science Center, Hefei, Anhui 230031, People's Republic of China.

PMID: 34898228
DOI: 10.1021/acs.nanolett.1c03682

Abstract

Selective partial photooxidation of CH₄ into value-added chemicals under mild conditions still remains a huge bottleneck. Herein, we design positively charged metal clusters anchored on a three-dimensional porous carbon aerogel. With 0.75FeCA800-4 as an example, X-ray photoelectron spectra and Raman spectra disclose that the iron sites are positively charged. In situ electron paramagnetic resonance spectra show that the Fe^δ+ sites could donate electrons to activate CH₄ into CH₄^- by virtue of the excited-state carbon atoms; meanwhile, they could convert H₂O₂ into ^•OH radicals under irradiation. In addition, in situ diffuse Fourier-transform infrared spectra suggest the CH₃OOH obtained is derived from CH₄ oxidation by the hydroxylation of *CH₃ and *CH₃O intermediates. Consequently, 0.75FeCA800-4 displays a CH₃OOH selectivity of near 100% and a CH₃OOH evolution rate of 13.2 mmol g_Fe^-1 h^-1, higher than those of most previously reported supported catalysts under similar conditions.

Keywords: carbon aerogel; metal clusters; methane partial photooxidation; mild conditions.