Ceria morphologies as Pd nanoparticles support for heterogeneous catalysis

Thesis

Ceria is well known for its unique properties in fast oxygen mobility and formation of oxygen vacancies which makes ceria an excellent catalyst support for metal nanoparticles. Promotional effect of ceria has been well established in a number of reactions including three-way catalyst and CO oxidation. These unique properties of ceria are dependent on the surface facets it exposes, where they can be enhanced by the exposure of high energy surfaces such as (100) and (110).

The work presented in this thesis involves controlling the surface exposed by the ceria support by making them into cube and rod morphology, which predominantly expose the (100) and (110) surface, respectively. Hence, the effect of these surfaces on the ceria support can be investigated. The ceria morphologies were deposited with Pd nanoparticles and their catalytic properties were tested on methane combustion and gas-phase formic acid decomposition reactions. In both of the catalyst test reactions, the Pd deposited on the ceria cubes support had shown superior catalytic properties compared to the Pd deposited on the ceria rods support, indicated by the former's higher activity, TOF and resistance to poisoning. Based on the characterisation techniques performed in this study such as TPR, ambient pressure XPS, STEM-EELS and pulse isotopic oxygen exchange, the enhanced catalytic properties of Pd/ceria cubes were attributed to the high energy ceria (100) surface which led to more favourable formation of oxygen vacancies and faster oxygen mobility.

Authors: Mahadi, A

• DOI: 10.5287/ora-kz8drxkpr
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: Nanoparticles; Morphologies; Ceria; Heterogeneous Catalysis
• Subjects: Chemistry, Inorganic