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

The significant role of perovskite defect chemistry through A-site doping of strontium titanate with lanthanum for CO ₂ 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 CO ₂ reduction at perovskite titanate cathode surfaces. Solid oxide electrolysers based on oxygen-excess La _0.2 Sr _0.8 Ti _0.9 Mn(Cr) _0.1 O _3+δ , A-site deficient (La _0.2 Sr _0.8 ) _0.9 Ti _0.9 Mn(Cr) _0.1 O _3-δ and undoped La _0.2 Sr _0.8 Ti _1.0 O _3+δ cathodes are evaluated. In situ infrared spectroscopy reveals that the adsorbed and activated CO ₂ 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 CO ₂ electrolysis.