Passivating Lattice Oxygen in ZnO Nanocrystals to Reduce its Interactions with the Key Intermediates for a Selective Photocatalytic Methane Oxidation to Methanol

Abstract An inevitable overoxidation process is considered as one of the most challenging problems in the direct conversion of methane (CH 4 ) to methanol (CH 3 OH), which is limited by the uncontrollable cracking of key intermediates. Herein, we have successfully constructed a photocatalyst, the Fe‐doped ZnO hollow polyhedron (Fe/ZnOHP), for the highly selective photoconversion of CH 4 to CH 3 OH under mild conditions. In situ experiments and density functional theory calculations confirmed that the introduction of Fe was able to decrease the energy level of the O 2 p orbital, which passivated the activity of lattice oxygen in ZnO nanocrystals. This passivation effect greatly weakened the interaction between *CH 3 and lattice oxygen, thus facilitating the conversion of *CH 3 O to *CH 3 intermediate rather than the direct desorption of *CH 3 O. As a result, Fe/ZnOHP exhibited excellent CH 3 OH generation rate (ca. 1009 μmol g cat −1 h −1 ) and selectivity (ca. 96 %) in the photocatalytic conversion of CH 4 at room temperature and low pressure.