Sub‐Second Time‐Resolved Surface‐Enhanced Raman Spectroscopy Reveals Dynamic CO Intermediates during Electrochemical CO₂ Reduction on Copper

Abstract

The electrocatalytic carbon dioxide (CO 2 )reduction reaction (CO 2 RR) into hydrocarbons is apromising approach for greenhouse gas mitigation, but many details of this dynamic reaction remain elusive.Here,time-resolved surface-enhanced Raman spectroscopy( TR-SERS) is employed to successfully monitor the dynamics of CO 2 RR intermediates and Cu surfaces with sub-second time resolution. Anodic treatment at 1.55 Vvs. RHE and subsequent surface oxide reduction (below À0.4 Vv s. RHE) induced roughening of the Cu electrode surface,w hich resulted in hotspots for TR-SERS,e nhanced time resolution (down to % 0.7 s) and fourfold improved CO 2 RR efficiency toward ethylene.W ithT R-SERS,t he initial restructuring of the Cu surface was followed (< 7s), after which astable surface surrounded by increased local alkalinity was formed. Our measurements revealed that ahighly dynamic CO intermediate,w ith ac haracteristic vibration below 2060 cm À1 ,isrelated to CÀCcoupling and ethylene production (À0.9 Vv s. RHE), whereas lower cathodic bias (À0.7 Vv s. RHE) resulted in gaseous CO production from isolated and static CO surface species with adistinct vibration at 2092 cm À1 .

Three-dimensional porphyrinic covalent organic frameworks for highly efficient electroreduction of carbon dioxide

“…1,2 The adsorption and catalytic conversion of CO 2 to valuable chemicals and fuels would be an ideal solution to decrease the CO 2 concentration in the atmosphere and alleviate the energy shortage. 3,4 Compared with other catalytic conversion methods, the CO 2 electroreduction reaction (CO 2 RR) using renewable energy resources for electricity can convert CO 2 to various value-added chemicals under mild and clean conditions. 5–11 Compared with other products, the two-electron involved product CO that has been widely used to produce synthetic liquid fuels by the Fischer–Tropsch process may be more easily produced via the CO 2 RR.…”

Interface regulation promoting carbon monoxide gas diffusion electrolysis towards C2+ products

“…15,16 Various studies have managed to verify the importance of the catalyst hydrophobicity, such as building a hydrophobic hierarchical structure, 16 and combining catalysts with a hydrophobe, creating a hydrophobic catalyst microenvironment. 7,14,17–20 These studies demonstrated the significant role of the balanced triple-phase in gas-involving electrochemical reactions. Nevertheless, much remains to be explored towards the optimal design with integrated efficient mass transfer and high ion conductivity.…”

“…Another peak located at B 536 cm À1 appeared at potentials below À0.3 V, which was assigned to CuO x /(OH) y mixed phase. 19,23 Raman signals emerged at B301 cm À1 (P1) and B394 cm À1 (P2), corresponding to the restricted rotation of adsorbed CO, Cu-CO stretching, respectively, and the intensity ratio of P2/P1 is a valid indicator of surface coverage of CO (Fig. 4a).…”

“…4a). 18,19 For Cu@8%PMMA-MS, the P2/P1 ratio increases as the potential becomes more negative, indicating a facilitated CO accessibility and fast CO adsorption. To further explore the role of gas availability, finite element analysis was used to simulate the reaction scenario (see ESI † and Fig.…”

Electrochemical Oxidative Dehydrogenation of Ethane to Ethylene in a Solid Oxide Electrolyzer

“…Consequently, a more energy-efficient and environmentally friendly process is desired. [3] Non-oxidative dehydrogenation of ethane is thermodynamically limited and generally carried out at high temperatures to achieve high conversion rates accompanied by undesirable coke production. [4] Oxidative dehydrogenation of ethane can overcome thermodynamic limitations and proceed at a lower temper-ature.…”