Enhanced CO2 electrolysis with in situ exsolved nanoparticles in the perovskite cathode

Abstract

The solid oxide electrolysis cell (SOEC) is generally recognized as the optimal electrochemical conversion device for CO₂ reduction reaction due to its high efficiency. However, the development of SOECs is limited by the lack of cathode materials with high electrocatalytic activity and stability. Perovskite cathodes exhibit redox stability at high temperatures, but their electrocatalytic activity remains limited. In this study, both A-site defects and B-site doping are designed for the perovskite La_0.5Sr_0.5TiO_3−δ. This cathode material promotes B-site exsolution through A-site defects, resulting in high-density nanoparticles. The in situ exsolved nanoparticles and the oxide substrate form a metal–oxide interfacial structure that significantly enhances the electrocatalytic activity and stability of the SOEC cathodes. The La_0.45Sr_0.45Ti_0.9Mn_0.1Fe_0.1O_3−δ cathode exhibits exceptional electroreduction performance under the operating conditions of 850 °C, producing a CO yield of 5.3 mL min⁻¹ cm⁻² with a current efficiency of 97.1%. Even after 100 h of operation, the SOEC maintains excellent durability. This work provides new ideas for improving surface and interface engineering.