Sungkyunkwan University · Energy
Professor Woong Hee Lee's research lab specializes in the design and development of advanced electrocatalysts for sustainable energy conversion and environmental remediation. The lab focuses on understanding and manipulating the electronic and structural states of transition metal catalysts—particularly cobalt and iridium-based materials—under operational conditions to enhance their activity and stability in oxygen evolution and hydrogen reactions. A key emphasis is placed on in-situ characterization techniques, such as X-ray absorption and Raman spectroscopy, to probe dynamic phase and spin-state changes during electrocatalysis. The lab also pioneers innovative electrode architectures, including single-atom catalysts and stackable membrane electrode assemblies, for efficient CO2 reduction to valuable chemicals like ethylene.
Figures are computed from collected data and may differ slightly.
Computational calculations and experimental studies reveal that the CoOOH phase and the intermediate-spin (IS) state are the key factors for realizing efficient Co-based electrocatalysts for the oxygen evolution reaction (OER). However, according to thermodynamics, general cobalt oxide converts to the CoO<sub>2</sub> phase under OER condition, retarding the OER kinetics. Herein, we demonstrate a simple and scalable strategy to fabricate electrodes with maintaining Fe-CoOOH phase and an IS state
The voltage reversal of water electrolyzers and fuel cells induces a large positive potential on the hydrogen electrodes, followed by severe system degradation. Applying a reversible multifunctional electrocatalyst to the hydrogen electrode is a practical solution. Ir exhibits excellent catalytic activity for hydrogen evolution reactions (HER), and hydrogen oxidation reactions (HOR), yet irreversibly converts to amorphous IrO<sub>x</sub> at potentials > 0.8 V/RHE, which is an excellent catalyst
Single-atom catalysts (SACs) possess the potential to achieve unique catalytic properties and remarkable catalytic mass activity by utilizing low-coordination and unsaturated active sites. However, smaller particles tend to aggregate into clusters or particles owing to their high surface energy. In addition, support materials that have strong interactions with isolated metal atoms, extremely large surface areas, and electrochemical stability are required. Therefore, sufficient information about
The electrochemical reduction of CO2 to ethylene has the potential to reduce greenhouse gas emissions while producing commodity chemicals for plastics; however, a scalable and feasible system for this remains a challenge. Herein, we report an efficient and stackable electrode design for the electrolysis of CO2 to ethylene. Using KOH-incorporated Cu nanoparticle (Cu-KOH) as the cathode in a zero-gap electrolyzer, Faradaic efficiency of 78.7% for C2 products was achieved at a current density of 28
For a CO2 reduction reaction (CO2RR), cation-exchange membrane (CEM)-based membrane electrode assembly (MEA) electrolyzers are among the most commercially viable systems; however, the acidic environment in these electrolyzers lowers the CO2RR selectivity. Herein, we outline broad methods for enhancing the performance of CEM MEA electrolyzers by providing an alkaline environment for the cathode. An appropriate amount of anion exchange ionomer, high-alkali cation concentration, and thick catalyst
Microdialysis sampling is an essential tool for in vivo neurochemical monitoring. Conventional dialysis probes are over 220 μm in diameter and have limited flexibility in design because they are made by assembly using preformed membranes. The probe size constrains spatial resolution and governs the amount of tissue damaged caused by probe insertion. To overcome these limitations, we have developed a method to microfabricate probes in Si that are 45 μm thick × 180 μm wide. The probes contain a bu
Microfabricated fluidic systems have emerged as a powerful approach for chemical analysis. Relatively unexplored is the use of microfabrication to create sampling probes. We have developed a sampling probe microfabricated in Si by bulk micromachining and lithography. The probe is 70 μm wide by 85 μm thick by 11 mm long and incorporates two buried channels that are 20 μm in diameter. The tip of the probe has two 20 μm holes where fluid is ejected or collected for sampling. Utility of the probe wa
The demand for non-noble bifunctional electrocatalysts for overall water splitting was increased for simplifying water-splitting systems and accelerating commercialization. Herein, oxygen vacancy-rich nanoporous nickel foam (NF) electrodes decorated with nanosized NiFe layered double hydroxide are fabricated by a facile and scalable electrochemical treatment using FeCl3 solutions as OER and HER electrocatalysts in an alkaline medium. The roles of Cl– and Fe3+ ions are analyzed by electrochemical
Sulfurized NiFeCo OER electrocatalysts for water splitting in alkaline conditions.
The electrochemical conversion of CO2 into CO using solar energy is the most efficient technique for artificial photosynthesis. However, many challenges remain, including the realisation of large-scale systems with high current density and stability. Herein, we report a carbon-supported tungsten-seed-based 3D silver dendrite ([email protected]) catalyst with abundant nanograin boundaries that exhibit enhanced CO2 reduction (CO2R) performance and stability. In zero-gap CO2 electrolyzer, [email pr
Technoeconomic analysis (TEA) sensitivity results for a CO<sub>2</sub>RR system with porous membrane (PM).
Development of first-row transition-metal-based catalysts for oxygen evolution is a desirable goal due to the low cost and abundance of transition metals, relative to iridium. However, low stability of first-row transition metal catalysts in acidic electrolytes has impeded practical application. In this work, we proposed the role of Sb in metal oxide which enhance electrochemical stability in acid media. While a Co-Fe mixed oxide exhibited poor stability in acid, a FeCoSbOx electrode demonstrate
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