Effect of bicarbonate on CO_(2) electroreduction over cathode catalysts  

作　　者：Wanyu Deng Tenghui Yuan Sai Chen Huimin Li Congling Hu Hao Dong Bo Wu Tuo Wang Jingkun Li Geoffrey A.Ozin Jinlong Gong 

机构地区：[1]Key Laboratory for Green Chemical Technology of Ministry of Education,School of Chemical Engineering and Technology,Tianjin University,300072,China [2]Collaborative Innovation Center of Chemical Science and Engineering(Tianjin),Tianjin 300072,China [3]Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Binhai New City,Fuzhou 350207,China [4]Department of Chemistry,University of Toronto,Toronto,Canada

出　　处：《Fundamental Research》2021年第4期432-438,共7页自然科学基础研究（英文版）

基　　金：This work is supported by the National Key Research and Development Program of China(2016YFB0600901);the National Natural Science Foundation of China(21525626,22038009,51861125104);the Program of Introducing Talents of Discipline to Universities(No.BP0618007)for financial support.

摘　　要：CO_(2) electroreduction (CO_(2) ER) using renewable energy is ideal for mitigating the greenhouse effect and closing the carbon cycle. Bicarbonate (HCO_(3)−) is most commonly employed as the electrolyte anion because it is known to facilitate CO_(2) ER. However, its dynamics in the electric double layer remains obscure and requires more in-depth investigation. Herein, we investigate the refined reduction process of bicarbonate by employing in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy. By comparing the product distributions in Ar-saturated KCl and KHCO_(3) electrolytes, we confirmed CO production from HCO_(3)^(−) in the absence of an external CO_(2) source. Notably, in contrast to an electric compulsion, negatively charged HCO_(3)− anions were found to accumulate near the electrode surface. A reduction mechanism of HCO3− is proposed in that HCO3− is not adsorbed over a catalyst, but may be enriched near the electrode surface and converted to CO_(2) and react over Au and Cu electrodes. The dependence of the CO_(2) ER activity on the local HCO3− concentration was subsequently discovered, which was in turn dependent on the bulk HCO3− concentration and cathodic potential. In particular, the local HCO3− concentration was limited by the cathodic potential, leading to a plateau in the CO_(2) ER activity. The proposed mechanism provides insights into the interaction between the catalyst and the electrolyte in CO_(2) ER.

关 键 词：Electrochemical reduction of CO_(2) ATR-SEIRAS BICARBONATE Catalyst-electrolyte interface 

分 类 号：O646[理学—物理化学]