Interfacial modification of Zn foil electrode with cationic surfactants enables efficient and selective CO production from CO₂ electroreduction

Abstract

The dynamic CTAB-modified electrode/electrolyte interface on Zn foil is effective to promote CO2 electroreduction to CO with enhanced Faradaic efficiency and current density.

Boosting CO2 electroreduction on a Zn electrode via concurrent surface reconstruction and interfacial surfactant modification

“…These values are consistent with the previously measured activity for the polycrystalline Zn electrode in KHCO 3 electrolytes. 11,15 In contrast to the pristine Zn foil electrode, all the OD-Zn electrodes exhibit much enhanced FE CO and j CO , and the OD-Zn electrode prepared by electrochemically reducing the 600 °C-annealed Zn electrode demonstrates the highest FE CO of 77.6% and a j CO value of 5.0 mA cm −2 , which are 2 and 10 times higher than those obtained with the pristine Zn foil electrode.…”

“…To rationalize the activity improvement of the OD-Zn electrodes, we compare the intrinsic activity of the pristine Zn foil with that of the OD-Zn electrodes by normalizing j CO to the electrochemical surface area (ECSA) (see the experimental details in the ESI†). 15,23 As shown in Fig. S3 and Table S1,† the ECSA of the OD-Zn electrodes is much higher than that of the pristine Zn foil, indicating the increased number of active sites, which is a result of the surface reconstruction induced by the in situ electrochemical reduction of grown ZnO nanostructures.…”

“…In recent years, various strategies including surface reconstruction, 10 surface modification/doping with heteroatoms, 11 the formation of alloys with other metals, 12,13 facet enginerring, 14 and interfacial modification 15–21 have been exploited to further improve the CO 2 RR performance of Zn electrocatalysts. Among them, surface reconstruction induced by successive oxidation and in situ electroreduction during the CO 2 RR is the most effective yet simple strategy to greatly improve the activity and selectivity of CO 2 RR due to the formation of more active sites with favorable reaction kinetics on reconstructed Zn electrocatalysts.…”

“…22 Apart from the surface reconstruction, it has also been proposed recently that constructing a modified electrode/electrolyte ( E / E ) interface via dynamic adsorption of organic molecules such as surfactants on the surface of polarized Zn electrocatalysts can efficiently modulate the interfacial microenvironment and thus largely enhance the CO 2 RR performance. 15–17 Thus, it would be expected that if the surface reconstruction can be properly synergized with interfacial modification, the CO 2 RR performance of Zn-based electrocatalysts could be further improved through synergistically engineering the surface microstructure for providing ample active sites and the E / E interfacial reaction environment for inhibiting the competitive HER while facilitating CO 2 adsorption and activation.…”

“…S5, ESI†), which indicates that the CTAB is physically adsorbed on the surfaces of the OD-Zn-CTAB electrode when it is unpolarized, consistent with the previous observation in the literature. 15…”