Ultrathin Co₃O₄ Layers Realizing Optimized CO₂ Electroreduction to Formate

Abstract

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.

Laser Fragmentation‐Induced Defect‐Rich Cobalt Oxide Nanoparticles for Electrochemical Oxygen Evolution Reaction

“…Such effects can enhance the charge transport in semiconductors and lower the adsorption energy of water molecules, respectively, which contribute to a higher electrocatalytic activity . Furthermore, the structure distortion helps to decrease the surface energy and hence endow the defective Co 3 O 4 with better structural stability …”

Nanostructured Materials for Heterogeneous Electrocatalytic CO2 Reduction and their Related Reaction Mechanisms

“…Metal oxides are another type of catalyst for the formation of formate.U pt on ow,s everal types of metal oxide,s uch as Co 3 O 4 ,G a 2 O 3 ,a nd SnO 2 ,h ave be found to be effective catalysts for the conversion of CO 2 into formate. [147][148][149][150][151][152][153][154] Lee et al investigated the effects of pH and the potential effect on the performance of CO 2 reduction on the SnO 2 electrode.T he SnO 2 nanocatalysts gave their best performance at À0.6 V(vs.RHE). TheFaradaic efficiency for formate reached 67.6 %a nd the activity of the catalyst was still 90 %after 5hwhile maintaining the stability of the oxide structure.…”

“…Based on the preparation of the partially oxidized Co catalysts,1 .72 nm thick Co 3 O 4 layers were prepared through af ast-heating strategy,w hich were ideal models of transition-metal-oxide-based atomic layers for CO 2 reduction (Figure 12 e). [154] Theas-prepared nanosheets contained abundant active sites and had high electrical conductivity,h ence showing promise for substantially promoting the CO 2 electroreduction. In the CO 2 electroreduction test, the 1.72 nm thick Co 3 O 4 layers had ac urrent density of 0.68 mA cm À2 at À0.88 Vv ersus SCE, over 20 times higher than that of bulk Co 3 O 4 (Figure 12 f).…”

Rapid Thermal Treatment of Reactive Sputtering Grown Nanocrystalline Co3 O4 for Enhanced All-Oxide Photovoltaics

“…Metal oxide materials are attractive for fabricating all‐oxide photovoltaics to harvest energy from the sun, because of their low‐cost and reliability. Moreover, the metal oxide materials can be tuned easily by doping . All‐oxide photovoltaics devices employing CuO, Cu 2 O, Fe 2 O 3 , Co 3 O 4 , and BiFeO 3 in a heterojunction configuration have been examined, with Cu 2 O/Ga 2 O 3 and BiFeO 3 /ZnO heterojunction showing the maximum conversion efficiency of ≈3.9% .…”