Work

Operando X-Ray Diffraction Analysis and DFT Calculations of Ni Cathode Oxidation during Electrochemical CO2 Reduction

Year: 2025

Type: article

Abstract: In this study, Ni cathode oxidation during electrochemical CO2 reduction (CO2 electrolysis) in a solid oxide electrolysis cell was studied via ex situ and operando X-ray diffraction (XRD) analyses as well as first-principles density functional theory (DFT) calculations. The XRD NiO-Ni peak ratio was used to compare the degree of Ni oxidation. Ex situ XRD analysis was performed to study a Ni/yttria-stabilized zirconia (YSZ) cathode surface after CO2 electrolysis at 1073 K, revealing that Ni oxidation was inhibited with increasing current density. Operando XRD analysis was performed to characterize the Ni/YSZ cathode surface during CO2 electrolysis at 873 K, revealing that the NiO(200)-Ni(111) peak ratio was low (<0.05) during CO2 electrolysis and rapidly increased to 0.7 without electrolysis after 10 min CO2 exposure. These findings indicated that electrolysis enhanced the oxidation tolerance of the Ni cathode immediately after electrolysis initiation. DFT calculations showed that CO2 reduction (CO2 → CO + O (O was filled into a electrolyte vacancy)) at the triple-phase boundary was more favorable than Ni oxidation (Ni + CO2 → NiO + CO) at the Ni (100) surface, suggesting that an increase in the CO2 reduction rate improved oxidation tolerance.

Source: Journal of The Electrochemical Society

DOI: 10.1149/1945-7111/add299

Authors: Ikkei Ban, Sho Higashidani, Hirotatsu Watanabe, Teppei Ogura, Yasuhiro Inada

Institutions: Ritsumeikan University, Kwansei Gakuin University

Language: English

Topic: Advancements in Solid Oxide Fuel Cells

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $1,950