Oxygen vacancies in Ce-Gd-O promoter boost the electrochemical oxidation of methanol on Pt/C

Oxygen vacancy-rich metal oxides are often added as promoters to Pt-based electrocatalysts to scavenge the adsorbed CO on Pt surface efficiently and increase the rate of methanol oxidation reaction (MOR). In the present work, oxygen vacancy-rich gadolinium doped ceria (Ce-Gd-O) is investigated as a promoter for MOR. This study shows that 0.1 mol Gd-doped CeO₂ promotes MOR activity of Pt/C by about 4.8 times. The first principles based DFT calculations on electron density and partial density of states reveal that Gd-doped CeO₂ exhibits superior catalytic activity. Further, the residual charge on Gd substituted at one Ce site in CeO₂ lattice aids in producing -OH ions and enhances MOR. The electrocatalytic activity of Pt-Ce_{1 − y}Gd_yO_{2 − δ}/C electrocatalyst is boosted due to the large number of oxyphilic species generated on the oxygen defect sites of Ce-Gd-O. The -OH groups can eliminate the adsorbed CO on Pt as CO₂ and help maintain the MOR activity.