Exploring the role of PdO and oxygen vacancies of Pd/CeO2 in bicarbonate hydrogenation

Abstract

The hydrogenation of bicarbonates in aqueous solutions using a Pd-based catalyst is an effective method for the production of formate. Herein, we synthesized finely dispersed Pd/CeO₂ catalysts via a two-step calcination method and evaluated their catalytic activities before and after the reduction process. The unreduced Pd/CeO₂ catalyst exhibited significantly higher activity for bicarbonate hydrogenation than the reduced catalyst. Although the activity declined after multiple cycles, regeneration via calcination effectively restored activity by converting metallic Pd back to highly active PdO. In addition, Pd incorporation and reaction conditions increased Ce^3 + contents and oxygen vacancies in CeO₂, enhancing bicarbonate adsorption and catalytic performance. These findings highlight the roles of PdO and oxygen vacancies in the CeO₂ support in the catalytic activity of Pd/CeO₂ catalysts for bicarbonate hydrogenation.