Pd/CeO₂ Interface with Abundant Oxygen Vacancies for Alkaline Hydrogen Evolution/Oxidation Reaction

Hydrogen evolution reaction and hydrogen oxidation reaction (HER/HOR) are two key reactions in the electrolysis of water to produce green hydrogen and fuel cells, respectively. However, the slow kinetics of HER/HOR under alkaline conditions and lack of catalysts with good activity and durability limit their development and application. Here, Pd nanoparticles supported by CeO2/C with abundant oxygen vacancies were synthesized for alkaline HER/HOR. The results of physical characterizations and electrochemical measurements indicated that small-size Pd nanoparticles were in full contact with CeO2, and charge transfer occurred at the Pd–CeO2 interface. The rich Pd–CeO2 interface and the interaction between metal and metal oxide carriers greatly improved the electrocatalytic activity of HER and HOR under alkaline conditions. The optimal Pd/CeO2/C exhibited excellent HER/HOR activity with a higher HER exchange current density (1.963 mA cm–2) than commercial Pt/C. Furthermore, the HER and HOR mass activity of Pd/CeO2/C reached 33 times and 9.2 times that of Pd/C, respectively. Pd/CeO2/C exhibited enhanced electrocatalytic stability due to the anchoring of Pd via abundant oxygen vacancy defects in CeO2/C. This work provides a meaningful reference for the rational regulation of metal–support interfaces and the application of metal-oxide–support-based electrocatalysts in electrocatalytic reactions.