Magda Barecka1,Mikhail Kovalev2,Marsha Zakir Muhamad2,Hangjuan Ren2,3,Joel Ager4,5,6,Alexei Lapkin2
Northeastern University1,Cambridge Centre for Advanced Research and Education in Singapore2,University of Oxford3,Lawrence Berkeley National Laboratory4,University of California, Berkeley5,Berkeley Education Alliance for Research in Singapore6
Magda Barecka1,Mikhail Kovalev2,Marsha Zakir Muhamad2,Hangjuan Ren2,3,Joel Ager4,5,6,Alexei Lapkin2
Northeastern University1,Cambridge Centre for Advanced Research and Education in Singapore2,University of Oxford3,Lawrence Berkeley National Laboratory4,University of California, Berkeley5,Berkeley Education Alliance for Research in Singapore6
Isotopes of carbon and kinteic effects related to the reactivity of carbon 12 vs carbon 13 have been widely explored to elucidate reaction mechanisms and metabolic pathways. We discovered that under the conditions of carbon dioxide (CO<sub>2</sub>) electroreduction in gas-diffusion electrodes, the kinetic isotope effect is much higher than expected based on known carbon kinetic isotope effect during CO<sub>2</sub> absorption in oceans or phosynthetic conversion of CO<sub>2</sub> to reduced forms of carbon. Our experiments demonstarte that CO<sub>2</sub> electroreduction strongly favours the conversion of the dominant isotope of carbon (<sup>12</sup>C) and discriminates against the less abundant, stable carbon <sup>13</sup>C isotope during all steps of the electrochemical process, and mostly at the triple phase interface created in gas-diffusion electrode based reactors. Using a natural abundance CO<sub>2</sub> feed, we experimentally demonstrate enriching of the <sup>13</sup>C fraction to ~1.3% (+18%) in a single pass reactor, being an unprecendently fast isotope separation. This talk will provide insights into the interfacial phenomena, being a part of a complex istope discrimination mechanism, which we anticipate to be applicable across a wide range of electrochemical systems.