Activating Inert Perovskite Oxides for CO₂ Electroreduction via Slight Cu²⁺ Doping in B-Sites

Perovskite oxides are proven as a striking platform for developing high-performance electrocatalysts. Nonetheless, a significant portion of them show CO₂ electroreduction (CO₂RR) inertness. Here a simple but effective strategy is reported to activate inert perovskite oxides (e.g., SrTiO₃) for CO₂RR through slight Cu²⁺ doping in B-sites. For the proof-of-concept catalysts of SrTi_1-xCu_xO₃ (x = 0.025, 0.05, and 0.1), Cu²⁺ doping (even in trace amount, e.g., x = 0.025) can not only create active, stable CuO₆ octahedra, increase electrochemical active surface area, and accelerate charge transfer, but also significantly regulate the electronic structure (e.g., up-shifted band center) to promote activation/adsorption of reaction intermediates. Benefiting from these merits, the stable SrTi_1-xCu_xO₃ catalysts feature great improvements (at least an order of magnitude) in CO₂RR activity and selectivity for high-order products (i.e., CH₄ and C₂₊), compared to the SrTiO₃ parent. This work provides a new avenue for the conversion of inert perovskite oxides into high-performance electrocatalysts toward CO₂RR.