Kwangjin An

Abstract A nanoparticle with well‐defined surfaces, prepared through colloidal chemistry, enables it to be studied as a model heterogeneous catalyst. The colloidal synthetic approach provides versatile tools to control the size and shape of nanoparticles. Traditional nucleation and growth mechanisms have been utilized to understand how nanoparticles can be uniformly synthesized and unprecedented shapes can be controlled. Now, the size of metal particles can be controlled to cluster regimes by us

The interaction of the metal and support in oxide-supported transition-metal catalysts has been proven to have extremely favorable effects on catalytic performance. Herein, mesoporous Co3O4, NiO, MnO2, Fe2O3, and CeO2 were synthesized and utilized in CO oxidation reactions to compare the catalytic activities before and after loading of 2.5 nm Pt nanoparticles. Turnover frequencies (TOFs) of pure mesoporous oxides were 0.0002–0.015 s(–1), while mesoporous silica was catalytically inactive in CO o

Recycling CO2 as a renewable carbon source for the production of high-value fuels and chemicals has drawn global attention lately as a promising method to mitigate climate change and lessen dependence on fossil fuels. Among the available CO2-recycling options, catalytic CO2 hydrogenation is the most realistic and attractive choice if the hydrogen is produced using a renewable energy source. Depending on the nature of the catalyst, CO2 hydrogenation has distinct reaction pathways, and various val

Gold nanoparticles (NPs) have attracted attention due to their superior catalytic performance in CO oxidation at low temperatures. Along with the size and shape of Au NPs, the catalytic function of Au-catalyzed CO oxidation can be further optimized by controlling the physicochemical properties of oxide-supporting materials. We applied a combinatorial approach of experimental analyses and theoretical interpretations to study the effect of a surface structure of supporting oxides and the correspon

We synthesized various hollow oxide nanoparticles from as-prepared MnO and iron oxide nanocrystals. Heating metal oxide nanocrystals dispersed in technical grade trioctylphosphine oxide (TOPO) at 300 degrees C for hours yielded hollow nanoparticles retaining the size and shape uniformity of the original nanocrystals. The method was highly reproducible and could be generalized to synthesize hollow oxide nanoparticles of various sizes, shapes, and compositions. Control experiments revealed that th

We synthesized uniformly sized, pencil-shaped CoO nanorods by the thermal decomposition of a cobalt-oleate complex, which was prepared from the reaction of cobalt chloride and sodium oleate. The diameters and lengths of the CoO nanorods were easily controlled by varying the experimental conditions, such as the heating rate and the amount of Co-oleate complex. The X-ray diffraction pattern revealed that the CoO nanorods have an extraordinary wurtzite ZnO crystal structure. These uniformly sized n

Monodisperse nanoparticles (NPs) of CoFe2O4 were synthesized as efficient catalyst precursors for CO2 hydrogenation to produce high value-added C2–C4 olefin products, which are important building blocks for the chemical industry. The resulting Na-promoted CoFe2O4 catalysts supported on carbon nanotubes (Na–CoFe2O4/CNT) exhibited high CO2 conversion (∼34%) and light olefin selectivity (∼39%), outperforming other reported Fe-based catalysts under similar reaction conditions. Their performance was

Selective isomerization toward branched hydrocarbons is an important catalytic process in oil refining to obtain high-octane gasoline with minimal content of aromatic compounds. Colloidal Pt nanoparticles with controlled sizes of 1.7, 2.7, and 5.5 nm were deposited onto ordered macroporous oxides of SiO2, Al2O3, TiO2, Nb2O5, Ta2O5, and ZrO2 to investigate Pt size- and support-dependent catalytic selectivity in n-hexane isomerization. Among the macroporous oxides, Nb2O5 and Ta2O5 exhibited the hi