Crucial Effect of Surface Oxygen Species on CO2 Electroreduction Performance in Ti@Cu Single Atom Alloys

22 December 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Here, we theoretically screened and explored the catalytic mechanism of electrocatalytic CO2 reduction reaction (eCO2RR) on Ti@Cu single atom alloy (SAA) and its oxidized variants (O-Ti@Cu and OH-Ti@Cu), focuseing on the effect of surface oxygen species on catalytical activity and selectivity under varying acidity and applied potential. Thermodynamically, Ti@Cu can be easily synthesized and oxidized in an aqueous solvent, as indicated by its low formation energy (-1.60 eV) and free energy (-0.92 eV) for oxidation. Catalytically, the introduction of bystander oxygen species facilitates the hydrogenation of residual *O after the generation of C2 products in eCO2RR on the Ti@Cu surface. This results in an inclination for eCO2RR on Ti@Cu to predominantly produce C1 product CH4 (ΔGRDS = 0.51 eV), while on the O-Ti@Cu and OH-Ti@Cu surfaces, there is a respective tendency towards the production of C2 products CH2CH2 (ΔGRDS = 0.51 eV) and CH3COOH (ΔGRDS=0.45 eV). Importantly, the potential required for eCO2RR on pure Ti@Cu is 0.70 V, notably lower than the 0.86 V needed for the *O hydrogenation. This confirms the stability of oxygen species (*O and *OH) on Ti@Cu under electrochemical conditions. Furthermore, the catalytic mechanism under varying electrochemical conditions (different potential and acidity) revealed that Ti@Cu favored CH4 production at pH = 1, 7, and 13, whereas both O-Ti@Cu and OH-Ti@Cu surfaces tended to produce CH2CH2 and CH3COOH at pH 1 and CH4 at pH = 7 and 13. This study contributes to our understanding of the catalytic mechanism of eCO2RR under realistic electrochemical conditions.


Density functional theory calculation
Electrocatalytic CO2 reduction
Single Atom Alloy
Oxygen Species

Supplementary materials

Supporting Information files
The Supporting Information contains detailed supported Figure and data about information on geometry, DOS analysis, electronic structure, calculated energies as a function of the applied potential and free energy profile, the changes of Gibbs free energy, pH-dependent and potential-dependent contour plot of adsorption energies and difference of adsorption energies and so on.


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.