Ultrathin Co3O4 Layers Realizing Optimized CO2 Electroreduction to Formate.

Electroreduction of CO₂ into hydrocarbons could contribute to alleviating energy crisis and global warming. However, conventional electrocatalysts usually suffer from low energetic efficiency and poor durability. Herein, atomic layers for transition-metal oxides are proposed to address these problems through offering an ultralarge fraction of active sites, high electronic conductivity, and superior structural stability. As a prototype, 1.72 and 3.51 nm thick Co₃O₄ layers were synthesized through a fast-heating strategy. The atomic thickness endowed Co₃O₄ with abundant active sites, ensuring a large CO₂ adsorption amount. The increased and more dispersed charge density near Fermi level allowed for enhanced electronic conductivity. The 1.72 nm thick Co₃O₄ layers showed over 1.5 and 20 times higher electrocatalytic activity than 3.51 nm thick Co₃O₄ layers and bulk counterpart, respectively. Also, 1.72 nm thick Co₃O₄ layers showed formate Faradaic efficiency of over 60% in 20 h. [ABSTRACT FROM AUTHOR]