Dual-Metal Single Atoms with Dual Coordination for the Domino Synthesis of Natural Flavones
Xin Zhao, Ruiqi Fang, Fengliang Wang, Xiangpeng Kong, Yingwei Li
Abstract
High Resolution Image Download MS PowerPoint Slide The regulation of coordination configurations of single-atom sites is highly desirable to boost the catalytic performances of SA catalysts. Here, we demonstrate a versatile complexation-deposition strategy for the synthesis of 13 kinds of dual-metal SA site pairs with uniform and exclusive coordination configurations. The preparation is specifically exemplified by the fabrication of Cu and Co single-atom pairs with the co-existence of N and P heteroatoms through etching and pyrolysis of a pre-synthesized metal–organic framework template. Systematic characterizations reveal the uniform and exclusive coordinative configuration of Cu and Co SA sites in CuN 4 /CoN 3 P 1 and CuN 4 /CoN 2 P 2, over which the electrons are unsymmetrically distributed. Impressively, the CuN 4 /CoN 2 P 2 site pairs exhibit significantly enhanced catalytic activity and selectivity in the synthesis of a variety of natural flavonoids in comparison with the CuN 4 /CoN 3 P 1 and CuN 4 /CoN 4 counterparts. Theoretical calculation results suggest that the unsymmetrical electron distribution over the CuN 4 /CoN 2 P 2 sites could facilitate the adsorption and disassociation of oxygen molecules via reducing the energy barriers of the generation of the key intermediates and thus kinetically accelerate the oxidative-coupling reaction process.