Ultrathin Co₃O₄ Layers Realizing Optimized CO₂ Electroreduction to Formate

Abstract

Abstract Electroreduction of CO 2 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 Co 3 O 4 layers were synthesized through a fast‐heating strategy. The atomic thickness endowed Co 3 O 4 with abundant active sites, ensuring a large CO 2 adsorption amount. The increased and more dispersed charge density near Fermi level allowed for enhanced electronic conductivity. The 1.72 nm thick Co 3 O 4 layers showed over 1.5 and 20 times higher electrocatalytic activity than 3.51 nm thick Co 3 O 4 layers and bulk counterpart, respectively. Also, 1.72 nm thick Co 3 O 4 layers showed formate Faradaic efficiency of over 60 % in 20 h.