Atomic Layer Deposition Prepared Nanostructured Materials For Various Catalytic Reactions

"Atomic layer deposition (ALD) has been widely used for thin film coating and metal nanoparticles (NPs) preparation. In this report, the applications of ALD prepared nanostructured materials in catalysis were examined. Highly dispersed Pt monometallic catalysts with different substrates and multi-walled carbon nanotubes (MWCNTs) supported Pt-Co bimetallic catalysts were synthesized by ALD for selective hydrogenation of [alpha], [beta]-unsaturated aldehydes to unsaturated alcohols (UA). Pt/MWCNTs showed the highest selectivity of UA in selective hydrogenation of citral, as compared to Pt/SiO2, Pt/ALD-Al2O3, and Pt/[gamma]-Al2O3. After adding Co, the highest selectivity was achieved with high conversion in hydrogenation of both cinnamaldehyde and citral over an optimized Pt-Co/MWCNTs catalyst. Highly dispersed Pt-Co/MWCNTs bimetallic catalysts were also used for hydrogenolysis of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) reaction. High yield of DMF (> 90%) was achieved in hydrogenolysis of HMF over an optimized Pt-Co/MWCNTs catalyst after 8 hr of reaction time under mild conditions. Fe NPs and single atoms were deposited on various substrates via ALD. Fe/SiO2 NPs showed a high activity in CO oxidation reaction with a long-term stability at high temperature. The TiO2 NPs deposited with Fe single atoms showed the highest activity and had an up to six-fold photocatalytic activity enhancement over pure TiO2. CeO2 ALD and ZrO2 ALD were also applied on TiO2 to boost the photocatalytic activity of TiO2, and both two methods improved the photocatalytic efficiency of TiO2 significantly"--Abstract, page iv.