报告题目：Electrochemical reduction of CO₂ on immobilized Cobalt protoporphyrin

报告人：沈静，荷兰莱顿大学博士，湖南工程学院 副教授

邀请人：申燕教授

时 间：2016年10月21日下午14:30-15:30

地 点：武汉光电国家实验室（筹）A202

摘要：

CO₂ is the most notorious greenhouse gas, which has caused and will continue to cause climate change. The abundance of the CO₂ resulting from the excessive combustion of fossil fuels makes it a perfect raw material to produce valuable fuels. Among diverse methods, electrocatalytic reduction of CO₂ using renewable energies seems to be a promising long-term objective.

Herein, we report on electrochemical reduction of CO₂ on a simple, cheap and commonly available molecular catalyst to 8-electron transferred product methane. The catalytic system is a pyrolytic graphite (PG) electrode coated with cobalt protoporphyrin (Co-PP), turning over CO₂ to methane in an aqueous acidic solution (pH=1-3) with a moderate overpotential (~ 0.5-1V). In the absence of buffer anions, the catalytic system shows higher activity and different selectivity. At pH=1, methane and H₂, which is a competing product, are the only gas products. The CO formation is observed at pH=2 together with the methane and H₂ as products. The most important aspect of the pH effect is that there is a potential range at which the CO and methane is formed while there is no sign of the formation of H₂. This means that we can control the selectivity of the electrochemical reduction of CO₂ by tuning the experimental conditions. The role of proton is understood by comparing the voltammetry of H₂ evolution reaction on Co-PP at different pH (1-3). Besides, in order to get an insight of the mechanism, electrochemical reduction of potential intermediates was also conducted.