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Converting CO 2 to highly demanded fuels or chemicals is able to achieve substantial economic and environmental benefits. Herein, a series of Pd/P–CeO 2 –Al 2 O 3 coatings on foam ceramics with particular morphologies including mesh, rod, plate, as well as mixed mesh and plate, are successfully prepared. The mesh Pd/P–CeO 2 –Al 2 O 3 coatings (MC) supported on ceramic displayed much higher catalytic activity and better selectivity than those of catalysts with other morphological Pd/P–CeO 2 –Al 2 O 3 coatings. The CO 2 conversion and CH 4 selectivity of MC were up to 85.9% and 100%, respectively. The superior catalytic performance was ascribed to the strong MSI effect, high hydrogen storage capacity, abundant oxygen vacancies, and metal sites, as well as moderately basic sites, which were characterized by TEM, XPS, CO 2 -TPD, and H 2 -TPD. More importantly, the intermediates and possible reaction pathways were systematically investigated by in situ FTIR. And the high performance of MC mainly comes from the accelerated conversion of carbonate and the hydrogenation of the generated monodentate formate. Overall, the catalytic performance of Pd/P–CeO 2 –Al 2 O 3 coatings supported on ceramic can be facilely regulated and optimized by accurately devising the morphology of the Pd/P–CeO 2 –Al 2 O 3 coatings, which offers a novel perspective for high-performance CO 2 methanation. [ABSTRACT FROM AUTHOR]

Ce–P/γ-Al 2 O 3 coatings applied with the freeze-drying technique were deposited on foam ceramics before being further prepared as Pd catalysts. According to the research, phosphoric acid replaced the hydroxyl on the surface of γ-Al 2 O 3 to produce polyhydroxy P-containing sites that readily attracted cerium oxide. The palladium oxide was then embedded into the cerium oxide vacancy. The impacts of the drying technique on the catalysts were investigated, and the results indicated that freeze drying created a special coating with a large specific surface area and uniform mesoporous structure by inhibiting nanoparticle agglomeration. H 3 PO 4 's altering action was augmented to boost the number of active sites and the percentage of weakly acidic sites. Due to better P–Ce interactions, more Ce3+ was added into CeO 2 , which created numerous oxygen vacancies. By adjusting the P-containing sites, the dispersion of cerium oxide and the active phase could be controlled, which aided the activation and spillover of hydrogen. Furthermore, the capacity for oxygen adsorption and desorption was enhanced, and the amount of adsorbed oxygen species increased. As a result, the freeze-drying technique improved the advantages of the Ce–P/γ-Al 2 O 3 coating, increasing the conversion and selectivity of CO 2 methanation to 81% and 94%, respectively, and lowering the complete conversion temperature of CO oxidation to 116 °C. This research has a guiding influence on the development of foam ceramic-loaded palladium catalysts in the fields of energy and the environment. [ABSTRACT FROM AUTHOR]