Development of Powder Atomic Layer Deposition Strategies for Precision-Engineered Metal Oxide Catalysts for Renewable Feedstocks

Batliwala, Shagufta (2026) Development of Powder Atomic Layer Deposition Strategies for Precision-Engineered Metal Oxide Catalysts for Renewable Feedstocks PhD thesis, University of Liverpool.

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Abstract

Replacing the unsustainable virgin petrochemical-derived feedstock chemicals with ones derived from waste or renewable sources is necessary for a sustainable, cleaner future. Conventional catalysts used in industrial petrochemical processes are often incompatible with renewable feedstocks, as they exhibit poor selectivity and are prone to deactivation under the operating conditions required for bio-based processes. Atomic layer deposition (ALD), which enables atomic-scale, precise deposition, was explored in this thesis to nanoengineer advanced yet cost-effective catalysts for renewable feedstock applications. Depositions were conducted on low-cost, earth-abundant, sustainable support particles using a bespoke pulsed fluidised bed-style powder adapter in an OpAL reactor. Investigations revealed that back-streaming from the pump, a shift in the reactor configuration, extended outgassing from the powder, and inadequate fluidisation caused non-uniform and non-ALD depositions on the powders. Mitigation strategies ensured atomic-scale, precise deposition on powders by maintaining unidirectional flow, operating within the ALD temperature window, suppressing gaseous outgassing from powders, and ensuring uniform gas exposure of all particles. A series of engineered, supported mixed metal oxide catalysts (Mo-V-Al oxide) was prepared and evaluated for the green production of maleic anhydride from bio-derived furfural. Catalytic activity in light of the mechanistic insights gained using ICP-OES, LEIS, and STEM-EDX revealed that a 93.7% furfural conversion was achieved when the surface was V-rich, contained a high number density of nucleation clusters (2 nm), exhibited an elemental mass ratio of 37:1 for V:Mo, and was loaded with only 0.26 wt% V, 0.007 wt% Mo and 0.22 wt% Al. These results demonstrated ALD’s unprecedented engineering precision and metal utilisation capability. Advanced catalytic supports for Fischer-Tropsch catalysis were prepared by incorporating shells of Al₂O₃ and TiO₂ onto high-surface-area coconut-shell-derived washed activated carbon (WAC) cores using ALD. The incorporation of Al₂O₃ shell enhanced the thermal stability of WAC without altering its morphology. TiO₂ shell was incorporated to facilitate strong metal -support interactions, ensuring dispersion of the active metals on the support and preventing sintering during high-temperature reduction. TiO₂ shells were uniformly deposited with the number of ALD cycles, even in mesopores, but substantial pore blocking occurred after 150 TiO₂ ALD cycles. Investigations using XRD, Raman, and STEM-EDX revealed deposition of crystalline anatase and brookite TiO₂ nanorods on Al₂O₃-modified WAC, a noteworthy outcome achieved at low deposition temperature of 120 °C. These results confirm the development of an easily transferable powder ALD process which enables precisely controlled deposition even on complex, porous structures. The methodologies and insights developed in this thesis lay the groundwork for nanoengineering next-generation, advanced catalysts with tunable properties for a circular chemical economy.

Item Type:	Thesis (PhD)
Uncontrolled Keywords:	atomic layer deposition, powder ALD, atomic-scale precision, advanced catalysts, renewable feedstocks
Divisions:	Faculty of Science & Engineering > School of Engineering > Materials, Design and Manufacturing Eng
Depositing User:	Symplectic Admin
Date Deposited:	30 Jun 2026 08:07
Last Modified:	30 Jun 2026 08:08
DOI:	10.17638/03198883
Supervisors:	Potter, Richard Chalker, Paul Manning, Troy Rosseinsky, Matthew
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3198883
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