Promoting Electrocatalytic Reduction of CO₂ to C₂H₄ Production by Inhibiting C₂H₅OH Desorption from Cu₂O/C Composite

Abstract

CO 2 RR) is regarded as one of the most attractive, which can not only convert CO 2 to high value hydrocarbon as fuels or chemical raw materials with high yields, but also be easily compatible to renewable energies. [2][3][4] Various hydrocarbons, that is, CO, HCOOH, CH 4 , C 2 H 4 , C 2 H 5 OH, etc., can be obtained during the CO 2 RR process. Among these products, multicarbon products (C 2+ ) are more attractive because of their higher economic values and higher energies densities with comparison to mono-carbon products (C 1 ). As one the most important products among C 2+ during CO 2 RR process, C 2 H 4 has attracted increasing interests owing to its wide applications as an important raw material for global chemical industries. However, as the conversion from CO 2 to C 2 H 4 involves CC coupling and diverse reaction pathways, it is more complex and difficult to produce C 2 H 4 than C 1 products during CO 2 RR process. As a result, the selectivity and activity for C 2 H 4 production is usually much lower than that for C 1 products. [5][6][7][8] In terms of the materials for C 2 H 4 production, Cu based materials are the most suitable candidates owing to the moderate adsorption of CO intermediates and the subsequent promotion for CC coupling. [9][10][11] Recently, great efforts have been made and various strategies have been developed to improve the C 2 H 4 selectivity and activity of Cu based materials, such as crystallinity [12] and size control [13] to enhance the CO 2 adsorption and activation barrier, facet engineering, [14][15][16] doping and defect engineering, [17,18] grain boundary, [19,20] oxidation state, [21][22][23][24][25][26] and surface molecule engineering [27,28] to enhance the CO stability and promote CC coupling, etc. Although, the C 2 H 4 selectivity and activity has been greatly improved, the maximum value for C 2 H 4 faradaic efficiency (FE C2H4 ) is still not high enough to meet the criteria for practical applications. Therefore, from the aspect for practical applications, it is still necessary and a great challenge to further improve the selectivity and activity for C 2 H 4 production.Comparing to the relatively low selectivity of C 2 H 4 , the selectivity for C 2 products could be much higher (80-90%), as other C 2 products, such as C 2 H 5 OH, CH 3 CHO, CH 3 COOH, could be inevitably produced besides C 2 H 4 during CO 2 RR process. [9,17,29] The electrochemical CO 2 reduction reaction (CO 2 RR) has great potential in realizing carbon recycling while storing sustainable electricity as hydrocarbon fuels. However, it is still a challenge to enhance the selectivity of the CO 2 RR to single multi-carbon (C 2+ ) product, such as C 2 H 4 . Here, an effective method is proposed to improve C 2 H 4 selectivity by inhibiting the production of the other competitive C 2 products, namely C 2 H 5 OH, from Cu 2 O/C composite. Density functional theory indicates that the heterogeneous structure between Cu 2 O and carbon is expected to inhibit C 2 H 5 OH production and promote CC coupling, which fac...

Cu2O Nanoparticles Wrapped by N-Doped Carbon Nanotubes for Efficient Electroreduction of CO2 to C2 Products

“…These suggest that the Cu 2 O component did not undergo repeated oxidation processes, which is consistent with the results reported in other studies. 12,35 By comparing the XPS spectra and current− voltage curves, we observed a gradual decrease in Cu I (Figure 4d) accompanied by a decline in current density (Figure 4a). Obviously, Cu I species play a more crucial role in the formation of C 2 products.…”

“…Cu 2 O NPs were synthesized by chemical reduction . CuCl 2 (1.2 mmol) was dissolved in 398 mL of water.…”

“…Cu 2 O NPs were synthesized by chemical reduction. 12 CuCl 2 (1.2 mmol) was dissolved in 398 mL of water. After stirring for 30 min, 1 mL of NaOH (4.8 mmol) solution was added dropwise to the above solution and stirred for 5 min.…”

Metal functionalization of two-dimensional nanomaterials for electrochemical carbon dioxide reduction

“…2). [54][55][56][57][58] The core step is to form the C-C bond, which always becomes the RDS. 59 Different bonding processes lead to different products, overpotentials, and FEs.…”

Microstructure Design Strategy for Molecularly Dispersed Cobalt Phthalocyanine and Efficient Mass Transport in CO2 Electroreduction

“…Electrochemical CO 2 reduction is an attractive route for converting CO 2 to value-added chemicals (e.g., CO, [1][2][3][4] HCOOH, [5,6] C 2 H 4 , [7,8] and C 2 H 5 OH [9] ) using renewable energy (e.g., wind and solar energy). [10] CO, one of the most fundamental chemical feedstock and intermediate, is a potentially reduced product due to its high production rate and selectivity, especially for operations at industrial current densities (>200 mA cm −2 ).…”