Calculations of Product Selectivity in Electrochemical CO2 Reduction

• Published in: ACS Catalysis
• Main Authors: Hussain, Javed, Jónsson, Hannes, Skulason, Egill
• Other Authors: Faculty of Physical Sciences (UI), Raunvísindadeild (HÍ), School of Engineering and Natural Sciences (UI), Verkfræði- og náttúruvísindasvið (HÍ), Háskóli Íslands (HÍ), University of Iceland (UI)
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Chemical Society (ACS) 2018
• Subjects: density functional theory calculations; electrocatalysis; electrochemical CO2 reduction reaction; reaction mechanism; selectivity; Koltvíoxíð; Raffræði; Vetni; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/1478; https://doi.org/10.1021/acscatal.7b03308

Publisher's version (útgefin grein). CO2 can be reduced electrochemically to form valuable chemicals such as hydrocarbons and alcohols using copper electrodes, whereas the other metal electrodes tested so far mainly form CO or formate, or only the side product, H2. Accurate modeling of electrochemical reaction rates including the complex environment of an electrical double layer in the presence of an applied electrical potential is challenging. We show here that calculated rates, obtained using a combination of density functional and rate theory, are in close agreement with available experimental data on the formation of the various products on several metal electrodes and over a range in applied potential, thus demonstrating the applicability of the theoretical methodology. The results explain why copper electrodes give a significant yield of hydrocarbons and alcohols, and why methane, ethylene, and ethanol are formed in electroreduction rather than methanol, which is the main product when H2 gas reacts with CO2 on copper catalyst. The insight obtained from the calculations is used to develop criteria for identifying new and improved catalysts for electrochemical CO2 reduction. We thank Marc Koper, Jens K. Nørskov, Andrew Peterson, Jan Rossmeisl and Anna Garden for helpful discussions. This work was supported by Nordic Energy Research through the “Nordic Initiative for Solar Fuel Development”, the Icelandic Research Fund, the University of Iceland Doctoral Scholarship Fund, and the Academy of Finland FiDiPro program (grant 263294). Peer Reviewed