Publications by authors named "Umair Sultan"

Article Synopsis
  • The study focuses on how immobilizing GaPt liquid metal alloy droplets on specially designed supports can enhance catalytic performance by preventing droplet merging and losing active surface area.
  • Researchers used supraparticle (SP) supports with varying pore sizes to investigate how these sizes influence the stability of GaPt droplets during propane dehydrogenation reactions.
  • Results showed that larger pore sizes led to better stability of the GaPt droplets, reducing deactivation rates and confirming successful immobilization without changes before and after the reaction, highlighting the importance of pore size in catalyst support design.*
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Colloidal supraparticles are micrometer-scale assemblies of primary particles. These supraparticles have potential application in photonic materials, catalysis, gas adsorption, and drug delivery. Thus, the synthesis of colloidal supraparticles with a narrow size distribution and high yield has become essential.

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Supported catalytically active liquid metal solution (SCALMS) materials represent a recently developed class of heterogeneous catalysts, where the catalytic reaction takes place at the highly dynamic interface of supported liquid alloys. Ga nuggets were dispersed into nano-droplets in propan-2-ol using ultrasonication followed by the addition of Pt in a galvanic displacement reaction - either directly into the Ga/propan-2-ol dispersion () or consecutively onto the supported Ga droplets (). The galvanic displacement reaction between Ga and Pt was studied in three different reaction media, namely propan-2-ol, water, and 20 vol% water containing propan-2-ol.

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Water emulsified heavy fuel oil (HFO) has been a promising alternative fuel for reducing oil consumption and preventing environmental pollution. However, the intrinsic challenges such as fuel formula, emulsion stability, and preparation process normally limit its further applications in energy-saving and emission reduction applications. In this study, the glucose obtained from biomass was added to a dispersed-phase aqueous solution of water emulsified HFO to prepare a novel alternative emulsified fuel.

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Hypothesis: The applicability of the dynamic light scattering method for the determination of particle diffusivity under confinement without applying refractive index matching was not adequately explored so far. The confinement effect on particle diffusion in a porous material which is relevant for particle chromatography has also not yet been fully characterized.

Experiments: Dynamic light scattering experiments were performed for unimodal dispersions of 11-mercaptoundecanoic acid-capped gold nanoparticles.

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A drying droplet containing colloidal particles can consolidate into a spherical assembly called a supraparticle. Such supraparticles are inherently porous due to the spaces between the constituent primary particles. Here, the emergent, hierarchical porosity in spray-dried supraparticles is tailored via three distinct strategies acting at different length scales.

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Colloidal supraparticles are micron-scale spherical assemblies of uniform primary particles, which exhibit emergent properties of a colloidal crystal, yet exist as a dispersible powder. A prerequisite to utilize these emergent functionalities is that the supraparticles maintain their mechanical integrity upon the mechanical impacts that are likely to occur during processing. Understanding how the internal structure relates to the resultant mechanical properties of a supraparticle is therefore of general interest.

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