Comparing interfacial cation hydration at catalytic active sites and spectator sites on gold electrodes: understanding structure sensitive CO₂ reduction kinetics

Abstract

Site-specific vibrational probes were used to elucidate the interfacial solvation structure between catalytic active sites and inactive sites on a Au electrode to reveal a unique, opposing cation-dependent double layer structure at active sites.

A unifying mechanism for cation effect modulating C1 and C2 productions from CO2 electroreduction

“…Also, using the scanning electrochemical microscopic technique, the Koper group demonstrated an absence of CO 2 RR activity for CO formation without M + , which led them to propose a mechanism based on a M + -complexation (or coupling) to the CO 2 − intermediate in conjunction with their ab initio molecular dynamics (AIMD) simulation results 13 . Moreover, cation-dependent interfacial water structure has been exploited to understand the cation effect on the CO 2 RR, which yields different electric field strengths 25 , 26 , adsorption rate 27 , or surface-dependent solvation structure 28 . There further exist other general discussions on the cation effect to the electrocatalytic activity 29 , e.g ., site-blocking of reactants on the electrode or surface reconstruction, albeit it has not been directly linked with the cation effect on the CO 2 RR.…”

Probing Cation Effects on *CO Intermediates from Electroreduction of CO2 through Operando Raman Spectroscopy

“…The interfacial hydration structure of the cation can be influenced by the adsorption sites. 46 This finding contributes to our understanding of the complex interplay between cations and surface intermediates in the electrochemical systems. Relative FE tendency can be interpreted according to the cation changes (Figures S6 and S7).…”

Direct observation of bicarbonate and water reduction on gold: understanding the potential dependent proton source during hydrogen evolution

“…Due to the repulsive Coulomb force, OHis repelled by the negatively charged Au electrode and is expected to diffuse rapidly into the electric double layer. Based on our previous works, the electric field for 0.1 M NaHCO3 at the electrode surface at -1.0 V is as high as ~4×10 7 V/cm 40,65 . The intense electric field represents a strong driving force for free OHto desorb and diffuse away from the surface.…”

“…Based on our previous works, the electric eld for 0.1 M NaHCO 3 at the electrode surface at −1.0 V is as high as ∼4 × 10 7 V cm −1 . 40,65 The intense electric eld represents a strong driving force for free OH − to desorb and diffuse away from the surface. Outside of the outer Helmholtz plane (OHP), OH − will form H-bond with surrounding water, and we can no longer observe the characteristic stretch of free OH − at 3650 cm −1 .…”