Quantifying Interface-Dependent Active Sites Induced by Topotactic Exsolution for CO<sub>2</sub> Electrolysis
Yuxiang Shen, Shuo Wang, Xiaoqin Chen, Houfu Lv, Yige Guo, Haolin Liu, Hongwu Zhao, Na Ta, Mingrun Li, Xiaomin Zhang, Yuefeng Song, Guoxiong Wang, Xinhe Bao
Abstract
Supported metal nanoparticles via in situ exsolution hold great promise for many fields including CO 2 electrolysis in solid oxide electrolysis cells. However, identifying and quantifying such in situ formed interfacial sites remain a challenge. Herein, we present a quantitative analysis of the inherent exsolution process and normalize the interfacial sites to the intrinsic activity of CO 2 electrolysis. CoFe/La 0.6 Sr 0.4 Cr 0.9 Co 0.1 O 3−δ (LSCC) interfaces are architecturally tailored by modulating the concentration of guest Fe cations, enabling precise control over the coverage of exsolved CoFe nanoparticles through a topotactic ion exchange strategy. The promotional role of Fe in facilitating Co cation exsolution is quantitatively investigated via X-ray absorption spectroscopy and Mössbauer spectroscopy. A quantitative correlation between the interfacial parameters of CoFe/LSCC and their intrinsic catalytic performance is well disclosed. CO 2 electrolysis performance is linearly positively correlated with the perimeter of the CoFe/LSCC interface, reaching a peak performance of 1.73 A cm –2 at an optimal interfacial perimeter of 29.3 μm μm –2 . This study offers valuable insights into quantitative research on metal/oxide catalysts for CO 2 electrolysis.