Enhancing CO2 electrolysis performance in solid oxide electrolysis cell using La-doped SrTiO3-δ composites

Abstract

Electrochemically reducing carbon dioxide by solid oxide electrolysis cells (SOECs) is a promising approach to minimize greenhouse gas emissions and generate high added value chemicals and fuels using renewable energy. However, the practical use of CO₂ electrolysis in SOECs faces challenges because of the scarcity of effective and stable cathode materials. This study explores La-doped SrTiO_3-δ composites as cathode materials for CO₂ electrolysis. By judiciously adjusting the La/Sr ratio, the perovskite structure's oxygen vacancies, lattice oxygen formation, and the content of Sr on the surface, a high CO₂ reduction activity is achieved. These adjustments enhance CO₂ adsorption and dissociation, leading to an improvement of catalytic activity and operational stability. La_0.4Sr_0.5TiO_3-δ shows a significantly enhanced CO₂ electrolysis performance with a high Faraday efficiency, a current density of 0.64 A cm⁻² at 850 °C and over 140 h of stability. The evaluation of various La-doped SrTiO_3-δ composites highlights their potential as efficient cathode materials for CO₂ electrolysis in SOECs.