Detection And Research Of CO₂^·- Radical Produced In The Electrocatalytic Reduction Of CO₂

With the shortage of energy and the problem of environmental pollution becoming more and more serious,the research on catalytic reduction of CO₂ has become a hot spot.In the process of electrocatalytic reduction of CO₂,a variety of free radicals are formed with the gradual transfer of protons（H⁺）and electrons（e-）,among which CO₂ electrons generate CO₂^·-radical is considered to reduce CO₂ at the first step.The kinetic information of CO₂^·-radical can help us understand the reaction mechanism of the reduction of CO₂,and has a guiding significance for the development of new catalyst materials.Therefore,the research on CO₂^·-radical kinetics is very important to understand the catalytic performance of the catalyst.Due to the extremely short life of CO₂^·-radical,the detection of free radicals using traditional electrochemical methods is a challenge.Scanning electrochemical microscope has the advantages of thin-layer cells and ultra-micro electrodes,which can capture short-lived intermediates under steady-state conditions.We studied the generation kinetics of CO₂^·-by used the substrate generation/tip collection mode of the scanning electrochemical microscope.At the same time,we use the electromagnetic field to prove that the magnetic current effect of free radicals improves the catalytic activity of the catalyst.The main results are summarized as following.1.We studied the CO₂^·-radical generation kinetics based on the substrate generation/tip collection working mode of scanning electrochemical microscope.Through the current and time response curve on the ultra-micro probe electrode,the formation process of CO₂^·-radical on Cu metal catalyst and Cu-Sn was syste bimetallic catalyst matically studied.By comparing a series of reaction rates calculated and found,it is found that the stability of CO₂^·-radical on the Cu-Sn bimetallic catalyst is higher and the conversion rate is higher.This verifies that the stability of CO₂^·-radical is directly proportional to the catalytic capacity of the catalyst.2.By applying an external magnetic field,the magnetic field effect of CO₂^·-radical was studied.By analyzing the change trend of the magnetic current,it is found that applying a magnetic field to the eletrocatalytic reduction of CO₂ can promote the conversion of the CO₂^·-radical pair from the singlet state to the triplet state through spin mixing.The catalytic activity of the catalyst shows that the state of CO₂^·-radical plays an important role in the catalytic activity of the catalyst.