Nanosized palladium loaded on porous ceria: A three-dimensional boosted electrocatalyst for electrooxidation of C1 compounds

The solution combustion synthesis was used for preparation of porous CeO₂ with two different fuels; glucose and citric acid, for combustion. The samples of porous CeO₂ are labeled as PCO_Glu and PCO_Cit. The surface area of PCO_Cit and PCO_Glu were estimated as 44.50 ± 0.12, and 47.72 ± 0.16 m² g⁻¹, respectively. The cavities acidity, OH groups on surface, and its bond strength to the active cerium sites are compared by measuring the pH of zero charges; that it was 11.95 ± 0.02, and 11.90 ± 0.03 for PCO_Cit and PCO_Glu, respectively. The nanosized palladium (NPd) was loaded on PCO_Glu and PCO_Cit via wetness incorporation. As-prepared nano-microstructure electrocatalysts are utilized in the electrooxidation of C1 compounds, including methanol, formaldehyde, and formic acid. The NPd-PCO_Glu presents higher electrocatalytic activity, stability and CO-tolerance ability for the electrooxidation of C1 compounds as compared to the NPd-PCO_Cit and NPd as non-supported palladium; So that, the performance of the modified electrodes increase in the order of NPd < NPd-PCO_Cit < NPd-PCO_Glu. The PCO with porous structural network affected on the electrochemical surface area, dispersion, and durability of NPd. It is effective the capability of removing the poisoning species of the electrooxidation of C1 compounds on NPd through the lattice oxygen, and the activation of an oxidation−reduction cycle between the high and low chemical valences of cerium, leading to improve the electrocatalytic efficiency of NPd. Lastly, the conversion of methanol to formaldehyde, and then to formic acid during electrooxidation is confirmed by using cyclic voltammetry.