Recently, Xiao Jianping, a researcher at Dalian Institute of Chemical Physics, Chinese Academy of Sciences, and Xia Chuan, a professor at University of Electronic Science and Technology of China, and Zeng Jie, a professor at China University of Science and Technology, have made new progress in the research of carbon dioxide (CO2) conversion, and developed a copper-based catalyst (Pb1Cu) with single atom alloying of lead, which realized the high activity and high selectivity reduction of CO2 to prepare formate, and explored the theoretical mechanism of this process.

Electro-reduction of CO2 with renewable energy is one of the means to achieve the goal of "double carbon". Formic acid is an energy carrier and can also be used as a liquid fuel for fuel cells. The preparation of formic acid by electro-reduction of CO2 is an important research direction of its resource utilization.

In the study, Xia Chuan and Zeng Jie prepared a copper-based catalyst Pb1Cu with monoatomic alloying of lead, which realized efficient electroreduction of CO2 to prepare formate, while ensuring the high selectivity and stability of the copper-based catalyst. Xiao Jianping's team further determined the catalytic mechanism and active sites of Pb1Cu, revealing the fundamental reasons for the high catalytic activity and selectivity of Pb1Cu.

Xiao Jianping's team established a "double channel" two-dimensional reaction phase diagram to simulate the trend change of CO2 reduction activity on different catalyst surfaces. It was found that, different from the activity trend established by the traditional single catalytic reaction channel, there were carboxylate (COOH*) mechanism and formate (HCOO*) mechanism in the process of preparing formate by electro-reduction of CO2, forming a "double channel" of catalytic reaction.

Therefore, the activity trend in the process of preparing formate by electro-reduction of CO2 reflects the nature of double active peaks. The study on the activity trend of the reaction phase diagram shows that the Pb1Cu catalyst mainly conforms to the HCOO* mechanism in the preparation of formate by electro-reduction of CO2, indicating that the better adsorption energy of HCOO* is the reason why the Pb1Cu catalyst shows high electro-reduction activity of CO2.

In addition, the copper site was proved to be the active site of Pb1Cu to catalyze the electro-reduction of CO2 to prepare formate. This study provides a new idea for designing electrocatalytic materials with high activity and specific selectivity.

Two-vertex one-dimensional (a) and two-dimensional (b) "reaction phase diagram" of formate prepared by electro-reduction of CO2. Comparison of theoretical and experimental activity trends based on dual channels (C). CO2 electroreduction free energy change diagram is used to study the selectivity (d)

of Pb1Cu monoatomic alloy. The related research results were published in Nature Nanotechnology recently with the topic of copper-catalysis d exclusive CO2 to pure formative acid conversion via single-atom alloying. The research work is supported by the Cooperation Fund of Clean Energy Innovation Research Institute of Chinese Academy of Sciences, the National Natural Science Foundation of China, and the strategic pilot science and technology project of Chinese Academy of Sciences (Class B) "Precise Construction Principle and Measurement of Functional Nanosystems".