The facilitated cathodic elementary reactions of solid oxide electrolysis cells for CO2 conversion over a Ce decorated La0.43Ca0.37Ti0.94Ni0.06O3−δ electrocatalyst

Abstract

A high temperature solid oxide electrolysis cell is recognized as a promising technology for CO₂ conversion (CO₂-SOEC). The development of alternative cathode materials substituting conventional Ni/YSZ is a great challenge for SOECs, on which multi-step elementary reactions (e.g., adsorption of CO₂, conversion of reaction intermediates, and desorption of CO) occur in succession. Herein, the Ce decorated La_0.43Ca_0.37Ti_0.94Ni_0.06O_3−δ perovskite (denoted as LCTNi-Ce) is synthesized and applied as a potential cathode electrocatalyst for a CO₂-SOEC. The in situ exsolution strategy and A-site deficiency enable the surface decoration of plenty of Ni nanoparticles (NPs) serving as efficient reactive sites. Furthermore, the Ce decoration leads to increased oxygen vacancy concentration, accelerated oxygen exchange rate and improved CO desorption capacity. The symmetrical half-cell measurement confirmed the boosted electrolysis performance in both CO₂/CO and CO₂/H₂ atmospheres. DRT analysis further evidences the facilitated oxygen ion transportation and gas adsorption/dissociation upon Ce decoration. Compared to a LCTNi cell, the LCTNi-Ce cell exhibits a significantly promoted current density of −0.557 A cm⁻² in 50% CO₂/50% H₂ at 800 °C and 1.3 V, and a reduced R_p value of 0.514 Ω cm⁻² under OCV condition.