Haimei Zheng1,2,Jiawei Wan1,2,Qiubo Zhang1,Sophia Betzler1,Junyi Shangguan1,2,Qi Zheng1,Xianhu Sun1,Xinxing Peng1,Xin Chen1,2,Rohan Dhall1,Karen Bustillo1
Lawrence Berkeley National Laboratory1,University of California, Berkeley2
Haimei Zheng1,2,Jiawei Wan1,2,Qiubo Zhang1,Sophia Betzler1,Junyi Shangguan1,2,Qi Zheng1,Xianhu Sun1,Xinxing Peng1,Xin Chen1,2,Rohan Dhall1,Karen Bustillo1
Lawrence Berkeley National Laboratory1,University of California, Berkeley2
The catalyst-electrolyte interfaces provide active sites which are fundamental for electrocatalysis. However, measuring structural dynamics of these delicate interfaces at atomic level remains challenging due to the limited experimental capabilities. Here, we report in situ electrochemical transmission electron microscopy (TEM) imaging of the interfacial evolutions of Cu-Cu<sub>2</sub>O core-shell nanowires during electrochemical carbon dioxide reduction reaction (CO<sub>2</sub>RR) using our newly developed polymer liquid cell. Our direct observations reveal that the catalyst-electrolyte interfacial interaction leads to several structural scenarios during CO<sub>2</sub>RR, including Cu mass loss, Cu<sub>2</sub>O shell fragmentation, and reshaping and growth of Cu nanoparticles. We find the competitive advantage of Cu-electrolyte interface is responsible for stabilizing Cu<sup>I</sup> species, and the abundant grain boundaries with disordered intermediate structures contribute to high catalytic efficiency. Our study offers insights into catalyst-electrolyte interfacial evolutions during CO<sub>2</sub> electroreduction, and it suggests opportunity to study diverse electrochemical processes at the atomic resolution.