Composite Cathode Based on Redox‐Reversible NbTi 0.5 Ni 0.5 O 4 Decorated with In Situ Grown Ni Particles for Direct Carbon Dioxide Electrolysis

In this work, ceramic NbTi 0.5 Ni 0.5 O 4 is reversibly transformed to nickel‐anchored electronic‐conducting Nb 1.33 Ti 0.67 O 4 composite for the use of direct carbon dioxide electrolysis at intermediate temperatures. The reduced composites Nb 1.33 Ti 0.67 O 4  + Ni demonstrate excellent electrical properties, which have been accordingly correlated to electrochemical performance of the composite cathode. The direct electrolysis of 100% CO 2 is then performed and the maximum Faraday current efficiency reaches as high as 65%. It is found that adding 3% H 2 O to CO 2 remarkably improves the electrolysis performances and the current efficiency is accordingly enhanced by approximately 20%. The reversible transformation between NbTi 0.5 Ni 0.5 O 4 and Nb 1.33 Ti 0.67 O 4  + Ni sample significantly contributes to the promising thermal and redox cycling performance while the anchored interface between Ni and Nb 1.33 Ti 0.67 O 4 improves cathode stability.