Yanming Cai1, Jiaju Fu1, Yang Zhou2, Yu-Chung Chang2, Qianhao Min3, Jun-Jie Zhu1, Yuehe Lin4, Wenlei Zhu5. 1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, People's Republic of China. 2. School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, 99164, USA. 3. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, People's Republic of China. minqianhao@nju.edu.cn. 4. School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, 99164, USA. yuehe.lin@wsu.edu. 5. School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, 99164, USA. wenlei.zhu@wsu.edu.
Abstract
Single-atom catalysts (SACs) are promising candidates to catalyze electrochemical CO2 reduction (ECR) due to maximized atomic utilization. However, products are usually limited to CO instead of hydrocarbons or oxygenates due to unfavorable high energy barrier for further electron transfer on synthesized single atom catalytic sites. Here we report a novel partial-carbonization strategy to modify the electronic structures of center atoms on SACs for lowering the overall endothermic energy of key intermediates. A carbon-dots-based SAC margined with unique CuN2O2 sites was synthesized for the first time. The introduction of oxygen ligands brings remarkably high Faradaic efficiency (78%) and selectivity (99% of ECR products) for electrochemical converting CO2 to CH4 with current density of 40 mA·cm-2 in aqueous electrolytes, surpassing most reported SACs which stop at two-electron reduction. Theoretical calculations further revealed that the high selectivity and activity on CuN2O2 active sites are due to the proper elevated CH4 and H2 energy barrier and fine-tuned electronic structure of Cu active sites.
Single-atom catalysts (SACs) are promising candidates to catalyze electrochemical n class="Chemical">CO2 reduction (ECR) due to maximized atomic utilization. However, products are usually limited to CO instead of hydrocarbons or oxygenates due to unfavorable high energy barrier for further electron transfer on synthesized single atom catalytic sites. Here we report a novel partial-carbonization strategy to modify the electronic structures of center atoms on SACs for lowering the overall endothermic energy of key intermediates. A carbon-dots-based SAC margined with unique CuN2O2 sites was synthesized for the first time. The introduction of oxygen ligands brings remarkably high Faradaic efficiency (78%) and selectivity (99% of ECR products) for electrochemical converting CO2 to CH4 with current density of 40 mA·cm-2 in aqueous electrolytes, surpassing most reported SACs which stop at two-electron reduction. Theoretical calculations further revealed that the high selectivity and activity on CuN2O2 active sites are due to the proper elevated CH4 and H2 energy barrier and fine-tuned electronic structure of Cu active sites.
Authors: Zhe Weng; Jianbing Jiang; Yueshen Wu; Zishan Wu; Xiaoting Guo; Kelly L Materna; Wen Liu; Victor S Batista; Gary W Brudvig; Hailiang Wang Journal: J Am Chem Soc Date: 2016-06-23 Impact factor: 15.419