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).

本研究在气体扩散电极（GDE）上制备了一种用于二氧化碳电化学还原制甲酸的新型树枝状氧化铋（Bi₂O₃）催化剂。本研究的工作假说为：（后）过渡金属氧化物前驱体在二氧化碳还原反应（CO2RR）条件下，会快速转化为亚碳酸盐相；该亚碳酸盐相在施加的工作电位下热力学不稳定，但可通过电解池中持续通入的CO₂实现动力学稳定。本项目的目标之一是研究原位（operando）条件下活性亚碳酸盐相的形成与时空演化过程，以及其在电位控制下停止通入CO₂时还原为金属铋（Bi）的过程。本项目的另一目标是通过断层成像技术，探究水性电解质在气体扩散电极（GDE）内的渗透行为，尤其是在厚度约25微米的多孔催化剂层中的渗透情况（水管理）。