Engineering Interfacial Low-Coordinated Mg<sub>3C</sub><sup>2+</sup>-O<sub>3C</sub><sup>2–</sup> Lewis Acid–Base Pairs on MgO for Cycloaddition of CO<sub>2</sub> with Epoxides
Juncong Yuan, Ranfei Fu, Sajid Mahmood, Xiuhui Zheng, Yichen Wang, Hao Yan, Yibin Liu, Yongquan Qu, Guang‐Yu Zhang, Bing Sun, Lin Wang, Wei Xu, Xiang Feng, De Chen, Chaohe Yang
Abstract
Activation of CO 2 faces great challenges due to its high chemical inertness. Herein, we constructed interfacial low-coordinated Mg 3C 2+ -O 3C 2– Lewis acid–base pairs on highly defective MgO by modulating the local coordination environment of the central Mg species for effective CO 2 activation. Through various in situ techniques, significantly enhanced CO 2 adsorption strength and capacity (∼80%) were detected qualitatively on the low-coordinated Mg 3C 2+ -O 3C 2– pairs, where O 3C 2– and Mg 3C 2+ function as Lewis base and acid sites, respectively. The MgO catalysts with rich Mg 3C 2+ -O 3C 2– Lewis acid–base pairs delivered 6.18 times higher activity compared to commercial MgO catalysts for propylene epoxide cycloaddition with CO 2 in the absence of solvent and cocatalyst. Also, the selectivity of propylene carbonate reached 99.3%. The MgO catalysts were also demonstrated successfully for cycloaddition between CO 2 and various epoxides. This work paves the way for the rational construction of active sites in oxide catalysts for CO 2 activation.