Ultrafine Pd species anchored on porous CeO₂ nanobundles as a highly efficient catalyst for methane oxidation

The design and development of efficient catalyst is very important for the removal of air pollutants through catalytic oxidation technology. Here, the Pd/CeO₂ catalysts were synthesized via in-situ thermal pyrolysis of Pd²⁺ doped Ce-MOF. The prepared Pd/CeO₂-NB catalyst exhibits nanobundles structure and highly dispersed Pd species, which shows superior performance in CO oxidation and CH₄ combustion at low temperature (<400 °C). The Raman, XPS, TPR and CO-IR reveal that the Pd/CeO₂-NB sample has a certain surface concentration of Pd⁰ species, and the formed Pd/PdO species boost the generation of oxygen vacancies, facilitating the dissociation of gas oxygen and the diffusion of lattice oxygen. Besides, possible reaction mechanism is also clarified by in-situ DRIFTS spectra, and main surface intermediate species (carbonate and carbon oxygenates) were confirmed. This study paves a way for the design of MOFs-based catalytic materials.