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

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 delta+ sites could donate electrons to activate CH4 into CH4- by virtue of the excited-state carbon atoms; meanwhile, they could convert H2O2 into center dot 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 gFe(-1) h(-1), higher than those of most previously reported supported catalysts under similar conditions.