Ewha Womans University · エネルギー
Professor Youngmi Lee's research lab specializes in the development of advanced electrochemical and optical microsensor technologies for real-time, in situ detection of biologically and environmentally relevant species such as nitric oxide, carbon monoxide, and hydrogen. The lab focuses on designing novel nanomaterials—particularly platinum-based and hybrid nanocomposites—to enhance sensor sensitivity, selectivity, and stability. A key research direction involves integrating scanning electrochemical microscopy (SECM) with optical microscopy (OM) to enable correlative electrochemical and topographical imaging at the micro- and nanoscale. The lab also explores electrocatalysts for sustainable energy applications, such as hydrogen evolution reaction (HER) catalysts based on iridium and iridium oxide nanostructures.
Figures are computed from collected data and may differ slightly.
A technique that combines scanning electrochemical microscopy (SECM) and scanning optical microscopy (OM) was developed. Simultaneous scanning electrochemical/optical microscopy (SECM/OM) was performed by a special probe tip, which consists of an optical fiber core for light passage, surrounded by a gold ring electrode, and an outermost electrophoretic insulating sheath, with the tip attached to a tuning fork. To regulate the tip-substrate distance, either the shear force or the SECM tip current
An improved miniature amperometric nitric oxide sensor design with a planar sensing tip (ranging from 150 microm to 2 mm in diameter) is reported. The sensor is fabricated using a platinized platinum anode and a Ag/AgCl cathode housed behind a microporous poly(tetrafluoroethylene) (PTFE; Gore-tex) gas-permeable membrane. Platinization of the working platinum electrode surface dramatically improves the analytical performance of the sensor by providing approximately 10-fold higher sensitivity (0.8
A planar-type amperometric dual microsensor for simultaneous detection of nitric oxide and carbon monoxide is presented. The sensor consists of a dual platinum microdisk-based working electrode (WE) and a Ag/AgCl counter/reference electrode covered with an expanded poly(tetrafluoroethylene) (Tetra-tex) gas-permeable membrane. The dual WE possesses two different platinized platinum disks (WE1 and WE2, 250 and 25 microm in diameter, respectively). The larger WE1 is further modified with electroche
A technique that combines scanning electrochemical microscopy (SECM) and optical microscopy (OM) was implemented with a new probe tip. The tip for scanning electrochemicaVoptical microscopy (SECM/OM) was constructed by insulating a typical gold-coated near-field scanning optical microscopy tip using electrophoretic anodic paint. Once fabricated, the tip was characterized by steady-state cyclic voltammetry, as well as optical and electrochemical approach experiments. This tip generated a stable s
Mesoporous nanocomposites of Pt-reduced graphene oxide (RGO)-layered titanate are synthesized by the reaction of a mixture of exfoliated layered titanate nanosheets, graphene oxide nanosheets, and H2PtCl6 with NaBH4 to investigate the effect of layered metal oxide nanosheets on the electrocatalyst performance of Pt–RGO nanocomposites. The obtained ternary nanocomposites are composed of a porous stacking assembly of layered titanate/RGO nanosheets with well-dispersed Pt nanocrystals whose particl
Nanocomposites of gold (Au) and iridium (Ir) oxide with various compositions (denoted as Au <sub>x</sub>Ir<sub>1- x</sub>O <sub>y</sub>, x = 0.05, 0.10, or 0.33, Au precursor molar ratio to Ir precursor) were synthesized via electrospinning and subsequent calcination method with two different solvent composition ratios of ethanol to N, N-dimethylformamide (DMF) in the electrospinning solution (ethanol/DMF = 70:30 or 50:50% v/v). Simple single-step electrospinning successfully fabricated a hierar
Hydrogen evolution reaction (HER) is of importance in energy conversion processes. This paper reports the facile synthesis of iridium/iridium oxide nanofibers (Ir/IrO2NFs) with diverse Ir and IrO2 relative composition ratios and their electrocatalytic HER activities. Highly porous Ir/IrO2NFs are simply synthesized via electrospinning and the following calcination at various temperatures (300–900 °C). Different calcination temperature alters the actual composition of Ir/IrO2NFs: The higher the te
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