Enhanced CO2 electrolysis with a SrTiO3 cathode through a dual doping strategy

Abstract

The significant role of perovskite defect chemistry through A-site doping of strontium titanate with lanthanum for CO₂ electrolysis properties is demonstrated. Here we present a dual strategy of A-site deficiency and promoting adsorption/activation by making use of redox active dopants such as Mn/Cr linked to oxygen vacancies to facilitate CO₂ reduction at perovskite titanate cathode surfaces. Solid oxide electrolysers based on oxygen-excess La_0.2Sr_0.8Ti_0.9Mn(Cr)_0.1O_3+δ, A-site deficient (La_0.2Sr_0.8)_0.9Ti_0.9Mn(Cr)_0.1O_3−δ and undoped La_0.2Sr_0.8Ti_1.0O_3+δ cathodes are evaluated. In situ infrared spectroscopy reveals that the adsorbed and activated CO₂ adopts an intermediate chemical state between a carbon dioxide molecule and a carbonate ion. The double strategy leads to optimal performance being observed after 100 h of high-temperature operation and 3 redox cycles, suggesting a promising cathode material for CO₂ electrolysis.