CO2 electroreduction under high current density conditions - an operando electrolyzer approach

A novel dendritic Bi2O3 catalyst for the electrochemical reduction of CO2 into formate is produced on a gas diffusion electrode (GDE). Our working hypothesis is that the (post) transition metal oxide precursor undergoes under CO2RR conditions a rapid transformation into a subcarbonate phase that is thermodynamically unstable at the applied potentials but kinetically stabilized through the continuous CO2 supply in the lectrolyzer. One goal of this project is to study the formation and spatio-temporal evolution of the active subcarbonate phase under operando conditions and its reduction into metallic Bi, e.g. when the CO2 supply is stopped under potential control. A further goal is to probe by tomography means the penetration of the aqueous electrolyte into the GDE and in particular into the ca. 25 micro meter thick porous catalyst film (water management).