Lanyaqian group of Nanjing Normal University has made a breakthrough in the field of electrocatalytic CO2 reduction

Recently, Professor LAN Yaqian's research group of Nanjing Normal University has made an important breakthrough in the study of the mechanism of electrocatalytic CO 2 reduction Relevant achievements were published in matter (DOI: 10.1016 / j.mat 2019.07.003) under the title of "disclosing CO 2 activation mechanism by hydroxyl − induced crystal structure transformation in electronic process" Electrocatalytic reduction of CO 2 is an effective way to convert CO 2 into energy products In this process, the first step requires a lot of energy to adsorb and activate the linear CO2 molecule, which is also the most critical step Secondly, in the three-phase system, it is difficult to monitor the participation of specific molecules, even electrolyte ions Because it is difficult to capture the dynamic process of the specific molecular change, the exploration of its mechanism has remained at the level of theoretical research, lack of direct structural evidence at the molecular level, which has also become a barrier difficult to overcome in the electrocatalytic reduction of CO2 It is of great significance to study the reaction mechanism of different reduction products, develop efficient catalysts and improve the performance of electrocatalytic CO 2 reduction A stable Oh coordinated metal organic framework compound (nnu-15) was designed and synthesized by the lanyaqian group of Nanjing Normal University as a catalyst model to simulate the surface state of the catalyst in alkaline environment and further explore the activation mechanism of CO 2 in the process of electrocatalysis The Faraday efficiency of nnu-15 is as high as 99.2% at - 0.6 V, and the catalytic time is over 110 h, and the selectivity is still over 96% in a wide potential range In the process of electrocatalysis, nnu-15 can capture CO 2 through Oh - coordinated by catalytic site, and then generate nnu-15-co 2 (intermediate nnu-15-co 2 with clear crystal structure) chelated by HCO 3 This shows that the catalytic center can capture and activate CO2 molecules in coordination with OH - The transition from single crystal to single crystal between nnu-15 and nnu-15-co2 provides solid evidence for revealing the activation mechanism of CO2 DFT calculation further shows that the initial geometry of O adsorption and C adsorption tends to form HCO3 - due to the participation of OH - ions This work proves that the coordination Oh - on the metal active center is of great significance for the chemisorption and activation of CO2 The formation of HCO3 - may be the necessary way for the mechanism of Electroreduction of CO2 in alkaline condition This important discovery may adjust the focus of future research, including the participation of OH - ions in the catalytic mechanism of various catalytic materials, and greatly promote the progress of Electroreduction of CO2 Huang Qing, a Ph.D student in the school of Chemical Sciences, is the first author of the article, and Professor LAN Yaqian is the corresponding author.