Largely Promoted C–H Activation in Methane with O<sub>2</sub> via d-Orbital Hybridization Induced by CuO<sub><i>x</i></sub> Supported on ZnO
Yufei Cui, Wenhao Zhou, Hui Yang, Yongqing Ma, Ganhong Zheng, Chuhong Zhu, Meiling Wang, Bin Chen
Abstract
Efficiently converting methane (CH 4 ) to C1 products such as CH 3 OH, HCHO, and CH 3 OOH is considered a promising route for the chemical industry, while the huge challenge of low CH 4 activation rate still remains. Here, the promising Cu/ZnO composite catalyst with CuO x supported on ZnO is synthesized to modify the electronic structure and utilized for CH 4 conversion. The fast e – transfer channel of ZnO → Cu → O 2 facilitates O 2 dissociation to • OOH, which promotes charge separation and, in parallel, enables CH 4 oxidation to • CH 3 by h + left in ZnO with the acceleration effect of in situ generated • OOH. Mechanistic studies revealed that additional d-π*/d-σ-orbital hybridization between the catalyst and adsorbed O 2 /CH 4 molecules plays decisive roles in O 2 and CH 4 activation, which resulted in the highest • CH 3 signal, so far as we know, and ultimately a remarkably high C1 products yield of 21.25 mmol g –1 h –1 with 100% selectivity over the optimized 1 wt % Cu/ZnO photocatalyst. This work offers valuable guidance for catalyst designation in CH 4 conversion in the presence of O 2 .