Fig. 9: Correlation of equilibrium reaction rates during electrolysis. | Communications Chemistry

Fig. 9: Correlation of equilibrium reaction rates during electrolysis.

From: In operando NMR investigations of the aqueous electrolyte chemistry during electrolytic CO2 reduction

Fig. 9

Evolution and correlation of the CO2/\({{{{{{{{{\rm{HCO}}}}}}}}}_{3}}^{-}\) equilibrium reaction rate (\({k}_{{{{{{{{\rm{exc}}}}}}}}}^{{{{{{{{{\rm{CO}}}}}}}}}_{2}/{{{{{{{{{\rm{HCO}}}}}}}}}_{3}}^{-}}\)) and the exchange rate between free electrolyte ions and xSIPs (\({k}_{{{{{{{{\rm{exc}}}}}}}}}^{{{{{{{{\rm{FI}}}}}}}}/{{{{{{{\rm{IP}}}}}}}}}\)) as a function of potential. With increasingly negative potential, it was found that \({k}_{{{{{{{{\rm{exc}}}}}}}}}^{{{{{{{{\rm{FI}}}}}}}}/{{{{{{{\rm{IP}}}}}}}}}\) decreases, while \({k}_{{{{{{{{\rm{exc}}}}}}}}}^{{{{{{{{{\rm{CO}}}}}}}}}_{2}/{{{{{{{{{\rm{HCO}}}}}}}}}_{3}}^{-}}\) increases simultaneously. Using T1 relaxation time experiments, it was shown that CO2 preferably is formed from \({{{{{{{{{\rm{HCO}}}}}}}}}_{3}}^{-}\) that is composing a xSIP, which suggests a catalytic activity of the electrolyte cation, e.g. Na+. The term xSIP represents ion pairs with one (x = 1) or two (x = 2) solvent layers between anion and cation.

Back to article page