Selective CH 4 Partial Photooxidation by Positively Charged Metal Clusters Anchored on Carbon Aerogel under Mild Conditions.

Selective partial photooxidation of CH 4 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 CH 4 into CH 4 - by virtue of the excited-state carbon atoms; meanwhile, they could convert H 2 O 2 into • OH radicals under irradiation. In addition, in situ diffuse Fourier-transform infrared spectra suggest the CH 3 OOH obtained is derived from CH 4 oxidation by the hydroxylation of *CH 3 and *CH 3 O intermediates. Consequently, 0.75FeCA800-4 displays a CH 3 OOH selectivity of near 100% and a CH 3 OOH evolution rate of 13.2 mmol g Fe -1 h -1 , higher than those of most previously reported supported catalysts under similar conditions.