Solid-State Electrochemical Carbon Dioxide Capture by Conductive Metal–Organic Framework Incorporating Nickel Bis(diimine) Units
Jinxin Liu, Mingyu Yang, Xinyi Zhou, Zheng Meng
Abstract
This paper presents the first implementation of electrically conductive metal–organic framework (MOF) Ni 3 (2,3,6,7,10,11-hexaiminotriphenylene) 2 (Ni 3 (HITP) 2 ) integrated with nickel bis(diimine) (Ni-BDI) units for efficient solid-state electrochemical carbon dioxide (CO 2 ) capture. The electrochemical cell assembled using Ni 3 (HITP) 2 as working electrodes can reversibly capture and release CO 2 through potential control. A high-capacity utilization of 96% and a Faraday efficiency of 98% have been achieved. The material also exhibits excellent electrochemical stability with its capacity maintained during 50 capture–release cycles and resistance to general interferences, including O 2, H 2 O, NO 2, and SO 2 . Capacity utilization of up to 35% is obtained at CO 2 concentrations as low as 1%. The capture of CO 2 at concentrations ranging from 1% to 100% requires exceptionally low energy consumption of only 30.5–72.4 kJ mol –1 . Studies combining spectroscopic experiments and computational approaches reveal that the CO 2 capture and release mechanism involves reversible carbamate formation on the N atom of the Ni-BDI unit in the MOF upon its one-electron redox reaction.