Publications by authors named "Seung Yeop Yi"

High-entropy alloy (HEA) nanoparticles possess finely tunable and multifunctional catalytic activity due to their extremely diverse adsorption sites. Their unique properties enable HEA nanoparticles to mimic the complex interactions of the redox homeostasis system, which is composed of cascade and multiple enzymatic reactions. The application of HEAs in mimicking complex enzymatic systems remains relatively unexplored, despite the importance of regulating biological redox reactions.

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Practical utilization of zinc-iodine (Zn-I) batteries is hindered by significant challenges, primarily stemming from the polyiodide shuttle effect on the cathode and dendrite growth on the anode. Herein, a feasible redox-active electrolyte has been introduced with tetraethylammonium iodide as an additive that simultaneously addresses the above mentioned challenges via polyiodide solidification on the cathode and the electrostatic shielding effect on the anode. The tetraethylammonium (TEA) captures water-soluble polyiodide intermediates (I , I ), forming a solid complex at the cathode, thereby suppressing capacity loss during charge/discharge.

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Single-atom nanozymes (SAzymes) constitute a promising category of enzyme-mimicking materials with outstanding catalytic performance. The performance of SAzymes improves through modification of the coordination environments around the metal center. However, the catalytic turnover rates of SAzymes, which are key measures of the effectiveness of active site modifications, remain lower than those of natural enzymes, especially in peroxidase-reactions.

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The sluggish kinetics of the hydrogen oxidation reaction (HOR) in alkaline conditions continue to pose a significant challenge for the practical implementation of anion-exchange membrane fuel cells. Developing single-atom catalysts can accelerate the pace of new HOR catalyst discovery for highly cost-effective and active HOR performance. However, single-atom catalysts (SACs) for the alkaline HOR have rarely been reported, and fundamental studies on the rational design of SACs are still required.

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Article Synopsis
  • Atomically dispersed iron catalysts (Fe-NCs) are promising alternatives to platinum-group metals for oxygen reduction reactions but perform poorly in practical fuel cell applications.
  • The researchers improved the performance of Fe-NCs by engineering their local environment using nitrogen-doped carbon and controlling the number of defects in the material.
  • These optimized defect-engineered Fe-NCs showed exceptional fuel cell performance, achieving power densities of 1.1 W/cm² in hydrogen/oxygen and 0.67 W/cm² in hydrogen/air systems, making them highly effective catalyst materials.
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Article Synopsis
  • The research focuses on enhancing gas sensor performance through morphological changes and preferred orientations in W-decorated NiO nanoigloos.
  • The morphological evolution led to a rough pyramidal surface and alignment of the (111) plane, which was explained by the van der Drift competitive growth model related to oxygen transport and chemical strain.
  • The sensor demonstrated excellent response and selectivity for NO detection, along with strong stability against interference from other gases and humidity.
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