(Invited) Electrochemical Reduction of Carbon Dioxide: Controlling Selectivity to Formic Acid and Methanol

Abstract

Currently, more than 80% of the world’s energy needs are met by burning fossil fuels. Supplies of these fuels are intrinsically limited and will eventually run out. Combustion of fossil fuels also generates carbon dioxide, whose rapidly increasing atmospheric concentration is suspected to be an accelerant of global warming. One solution for mitigating atmospheric concentrations of CO 2 is to electrochemically reduce these molecules into chemical fuels. If the energy used for these processes is generated from renewable sources such as solar and wind, we can envisage a chemical production cycle that is closed-loop with net zero carbon emission. In this talk, we share our works related to the development of catalysts for the selective electroreduction of CO 2 . We shall discuss our work on how copper catalysts, by a simple sulfur doping procedure, can be made almost exclusively selective for the reduction of CO 2 to formic acid. We shall also discuss a new class of catalysts based on zinc, for the selective formation of methanol. Through a series of control experiments and density functional theory calculations, we pinpoint strained undercoordinated Zn sites as the catalytically-active sites for methanol formation, in a reaction pathway mediated by adsorbed carbon monoxide and formaldehyde.