(Invited) Electrocatalytic Carbon Dioxide Conversion on Cu Catalyst

The efficient electrochemical conversion of CO2 to fuels or stock chemicals with high-energy density would be a major step forward in the introduction of a carbon neutral energy cycle, as it would allow for the direct low-temperature conversion of (photo)-generated electrical current to stored chemical energy, in a manner very similar to the way nature stores solar energy. The high activity and selectivity towards electrocatalytic conversion of CO2 can be achieved with careful selection of catalyst and electrolyte. Major progress in electrochemical CO2 reduction has been limited to two-electron involved products such as CO and formate. It has been known that Cu is prone to produce hydrocarbons, mainly C1 product such as methane and the formation of multi-carbon products via C-C coupling remains as one of the biggest scientific challenges to be resolved. The product selectivity of such conversion can be affected by the electrolyte composition and catalyst structure. Anion such as halides in the electrolyte nanostructures copper surface via electrochemical cycling which allows for a suppression of methane and an enhancement of ethylene and ethanol formation. On the other hands, cations have direct influence on CO2RR in which increasing the size of mono-valent cations can increase the selectivity and activity to C-C coupled products by lowering the pK a of the hydrated cations at the cathode. In addition, a new principle of catalyst design which controls an atomic-level catalyst structure to accelerate electrocatalytic activity and selectivity toward the formation of C-C bonds will be discussed.