Photocatalytic CH 4 -to-Ethanol Conversion on Asymmetric Multishelled Interfaces.

The selective oxidation of methane (CH 4 ) features attractive potentials in both mitigating global warming and producing value-added chemicals. However, due to the short-life and unpaired concentrations of reactive intermediates (such as ·OH, ·CH 3 , and CO), the selective formation of multicarbon products like ethanol has remained challenging. In this work, we developed a hollow multishelled CeO 2 @PdO@FeO x nanosphere catalyst with two asymmetric and closely connected interfaces, featuring efficient in-tandem photo-oxidation of CH 4 into ethanol with O 2 as the oxidant. The outer FeO x surface promotes the photoreduction of the oxazole atoms in O 2 . In the meantime, the two asymmetric PdO/FeO x and CeO 2 /PdO catalytic interfaces enable selective photoactivation of CH 4 to ·CH 3 and then to CO, respectively, and the hollow multishelled structure further facilitates the directional transport and coupling of the as-generated ·CH 3 and CO to produce ethanol. Under 100 mW·cm -2 light intensity and ambient conditions, the hollow multishelled CeO 2 @PdO@FeO x nanosphere photocatalyst exhibited a peak CH 4 -to-ethanol yield of 728 μmol·g -1 ·h -1 without photosensitizers or sacrificial agents, almost three times higher than the previous best reports on photocatalytic CH 4 oxidation to ethanol, suggesting the attractive potential of the asymmetric multishelled catalytic interfaces.