Enhancement of Methanol Oxidation Performance Over Pd/CeO2 Derived from MOF and Mechanism Investigation via In Situ Studies

A Pd/CeO2-M with high methanol oxidation performance was prepared from metal–organic framework (MOF). The reaction results indicate that the Pd/CeO2-M could achieve 100% methanol oxidation at 200 °C over the traditional Pd/CeO2-C at 350 °C. The high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Raman show that the Pd was uniformly distributed over the CeO2 that was rich in oxygen vacancies. The methanol temperature program surface reaction (MeOH-TPSR) demonstrates that the Pd/CeO2-M could effectively decompose methanol at a lower temperature with the assistance of oxygen vacancies compared with Pd/CeO2-C. Methanol oxidation was conducted with in-situ Raman, CO diffuse reflectance infrared Fourier transformed spectroscopy (CO-DRIFTS) and in-situ DRIFTS to elucidate the reaction mechanism and establish the structure–activity relationship. The oxygen vacancies have participated in the assistance of methanol oxidation, which was revealed via in-situ Raman. The CO-DRIFTS indicates that the chemisorbed CO was more in linear form, which demonstrates that the Pd particles were over CeO2-M with a smaller size. The in-situ DRIFTS experiments show the methanol could be further effectively oxidized to bidentate formate over Pd/CeO2-M with the assistance of oxygen vacancies. The Pd/CeO2-M catalysis and its enhancement mechanism studies provided a potential strategy in the VOC removal catalysis development. Graphical Abstract