Air pollution is one of the most substantial challenges of our era. It is a major contributor to climate change and a significant health hazard contributing to increased mortality or severe illness. Environmental catalysis is one of the most sustainable and effective solutions for reducing the emissions of undesirable pollutants in the atmosphere. Nonetheless, the effectiveness of pollutant removal greatly hinges upon the catalyst employed, necessitating the urgent development of exceptionally efficient catalysts. In comparison to the commonly employed precious metal catalysts, there has been a notable surge of interest in non-noble transition metal catalysts, such as copper and nickel-based catalysts. This interest is primarily due to their abundant availability, lower cost, and their considerable activities in environmental related reactions that are comparable to those of noble metal catalysts. However, there is still a pressing need to significantly enhance their low-temperature activity to meet application requirements. Increasing the metal dispersion to create more active sites and establishing a strong interaction between metals and supports are effective strategies to improve the catalytic performance of supported metal catalysts. However, achieving these improvements using simple and scalable preparation methods has posed a considerable challenge in the material science and environmental catalysis field. In this work, using hydroxyl-rich (OH-rich) CeO2 and ZrO2 as supports and a facile incipient wetness impregnation (IWI) method, we report the successful preparation of three sets of catalysts, including CuO/CeO2, CuO/ZrO2, and Ni/CeO2, with high metal dispersion and enhanced metal-support interactions. Our findings show that these catalysts prepared using OH-rich supports exhibited superior catalytic performance in environmental-related reactions, including CO oxidation, NO reduction by CO, selective catalytic oxidation of NH3 (NH3-SCO), and dry reforming of methane (DRM), respectively. Using various experimental techniques, including X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), N2 physisorption, X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), the effect of hydroxyls on Ce(OH)x and Zr(OH)x supports on the physicochemical properties of the catalysts was characterized in detail. Additionally, the structure-activity relationship and reaction mechanism on these newly developed catalysts were revealed. This study showcases the utilization of OH-rich supports to improve metal dispersion and strengthen the metal-support interaction, thereby improving the catalytic performance of supported transition metal catalysts. This research suggests that utilizing OH-rich supports holds great promise as an approach to designing highly efficient catalysts for important environmental catalysis applications.
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Doctor of Philosophy (Ph.D.)
College of Engineering and Computer Science
Civil, Environmental, and Construction Engineering
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
Almousawi, Murtadha, "Highly Dispersed Transition Metal Oxide Catalysts Achieved on Hydroxyl-Rich Supports for Environmental Catalysis" (2023). Electronic Theses and Dissertations, 2020-. 1867.
Restricted to the UCF community until August 2028; it will then be open access.