Promoting effects of pretreatment on Pd/CeO2 catalysts for CO oxidation

Unravelling Phosphorus-Induced Deactivation of Pd-SSZ-13 for Passive NOx Adsorption and CO Oxidation

“…The EDX mapping visualized the presence of certain areas with an enriching of both P and Pd elements (Figure S5 in the Supporting Information), while other elements (Si, Al, O) are distributed uniformly, confirming a close association between P and Pd species in the P-poisoned Pd-SSZ-13. P-induced Pd aggregation was also confirmed by CO pulse adsorption experiments, 28 which indicate that P-loaded Pd-SSZ-13 demonstrated a lower Pd dispersion and larger Pd particle size than the P-free counterpart (Figure S6 and Table S1 in the Supporting Information).…”

The upgrading role of Al at T1/T2 sites in stabilizing Pd ions over Pd-beta passive NOx adsorbers under a reducing atmosphere

“…Signals of CO 2 and H 2 were monitored using mass spectra. Typically, the reduction below 250 °C should be assigned to PdO reduction, 51,52 and the CO 2 formation is attributed to the reduction of Pd II ions accompanied by H 2 generation (due to the WGS reaction between CO and the hydroxyl groups). 53–55 This indicates the existence of PdOH species in Pd/beta.…”

Strong Metal–Support Interaction in Pd/CeO2 Promotes the Catalytic Activity of Ethyl Acetate Oxidation

“…A series of noble-metal-supported catalysts have been reported in the catalytic oxidation of ethyl acetate, such as Ru/SnO 2 , Ag/LaCoO 3 , Ag/CeO 2 , Au/CeO 2 , Pd/Cr 2 O 3 -ZrO 2 , and Pd/Al 2 O 3 , − and the performance of noble-metal-supported catalysts is significantly improved compared with that of certain supports because the strong metal–support interactions (SMSIs) enhance the surface oxygen vacancies, surface reactive oxygen species, and low-temperature redox ability. Among these noble metals, Pd has more abundant reserves and lower cost than other noble metals and can have a strong interaction with supports, showing high catalytic activity, so it is a critical material for the catalysis of VOCs. − As a stable, richly abundant, and cheap rare earth material, CeO 2 has become a hotspot of support material because of its excellent oxygen storage and release capacity, conversion capacity between valence states, and abundant oxygen vacancy, thus providing surface and pore structure for noble metal dispersions. − Moreover, CeO 2 has morphological diversity, and studies have shown that the morphology of CeO 2 has a significant impact on catalytic activity. − For example, Feng et al prepared three kinds of CeO 2 with different morphologies and found that the concentration of surface oxygen vacancies was affected by the morphology, which led to the difference in catalytic activity. At present, it has been found that the SMSIs on the interface of noble-metal-supported catalysts would significantly influence the activity and stability of the catalysts, , while the effect of support morphology on SMSI needs further research.…”