Encapsulated Co-Ni alloy boosts high-temperature CO electroreduction.

Electrochemical CO reduction into chemicals and fuels holds great promise for renewable energy storage and carbon recycling. Although high-temperature CO electroreduction in solid oxide electrolysis cells is industrially relevant, current catalysts have modest energy efficiency and a limited lifetime at high current densities, generally below 70% and 200 h, respectively, at 1 A cm and temperatures of 800 °C or higher. Here we develop an encapsulated Co-Ni alloy catalyst using SmO-doped CeO that exhibits an energy efficiency of 90% and a lifetime of more than 2,000 h at 1 A cm for high-temperature CO-to-CO conversion at 800 °C. Its selectivity towards CO is about 100%, and its single-pass yield reaches 90%. We show that the efficacy of our catalyst arises from its unique encapsulated structure and optimized alloy composition, which simultaneously enable enhanced CO adsorption, moderate CO adsorption and suppressed metal agglomeration. This work provides an efficient strategy for the design of catalysts for high-temperature reactions that overcomes the typical trade-off between activity and stability and has potential industrial applications.