
Si Young LeeUniversity of Michigan | U-M · Department of Mechanical Engineering
Si Young Lee
Doctor of Philosophy
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28
Publications
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Introduction
Additional affiliations
March 2021 - June 2022
September 2015 - February 2021
Education
September 2015 - February 2021
March 2008 - February 2015
Publications
Publications (28)
Synthesis of bimetallic electrocatalysts for CO 2 reduction using atomic layer deposition results in changes in chemical state and product selectivity.
Transition-metal-based solid-state electrocatalysts undergo dynamic phase transformation governed by the local electrochemical environment during operation, e.g., oxygen evolution/reduction( 1,2 ), hydrogen evolution( 3 ), and carbon dioxide reduction( 4 ). Electrochemical active species, often hidden before operation, can become evolved due to the...
Electrochemical CO 2 conversion is gaining attention as an important process for carbon fixation through the use of renewable electricity to address the climate change crisis. Copper is a unique single-element catalyst that can induce C-C coupling reactions to generate high-value-added compounds. The triple phase boundary has been successfully cont...
Back Cover In article number 2200074, Yun Jeong Hwang, Heejin Kim, Kwangyeol Lee, and co‐workers use a microfluidic system to synthesize hierarchical Cu2O nanocrystals with multiple steps (h‐Cu2O ONSs) by kinetics‐manipulated crystal growth. Due to the surface reconstruction of h‐Cu2O ONSs under electrochemical CO2 reduction, h‐Cu2O ONS catalysts e...
Electrochemical conversion of CO2 to fuels and chemicals as a sustainable solution for waste transformation has garnered tremendous interest to combat the fervent issue of the prevailing high atmospheric CO2 concentration while contributing to the generation of sustainable energy. Monometallic palladium (Pd) has been shown promising in electrochemi...
Copper‐based catalysts have attracted enormous attention due to their high selectivity for C2+ products during the electrochemical reduction of CO2 (CO2RR). In particular, grain boundaries on the catalysts contribute to the generation of various Cu coordination environments, which have been found essential for C—C coupling. However, smooth‐surfaced...
The direct electroconversion of captured CO2 is attracting attention as an alternative to the current energy-demanding CO2 separation processes. In conventional capturing media, the reaction inevitably takes place in the presence of bulky ammonium, leading to steric hindrance and low CO selectivity. Here, for the first time, we present a single ato...
The direct electroconversion of captured CO2 is attracting attention as the streamlined manner for the carbon capture and utilization, omitting energy-demanding CO2 separation processes. In amine-based conventional capturing media, however,...
Pd is one of the most effective catalysts for the electrochemical reduction of CO2 to formate, a valuable liquid product, at low overpotential. However, the intrinsically high CO affinity of Pd makes the surface vulnerable to CO poisoning, resulting in rapid catalyst deactivation during CO2 electroreduction. Herein, we utilize the interaction betwe...
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...
The electrochemical reduction of CO2 stores intermittent renewable energy in valuable raw materials, such as chemicals and transportation fuels, while minimizing carbon emissions and promoting carbon-neutral cycles. Recent technoeconomic reports suggested economically feasible target products of CO2 electroreduction and the relative influence of ke...
The direct electroreduction of CO2 to pure CO streams has attracted much attention for both academic research and industrial polymer synthesis development. Here, we explore catalytically very active, coral-structured Ag catalyst for the generation of pure CO from CO2-feeds in lab-bench scale zero-gap CO2 electrolyzer. Coral-shaped Ag electrodes ach...
Cu catalysts prepared by modifying bulk Cu foils have achieved high performance for value-added C2+ componds from electrochemical CO2 reduction (CO2RR), but active sites transformation can be affected by the bulk substrate which make it complex to design catalyst. Here, we newly introduce a simple electrospray pyrolysis synthesis to take advantage...
Electrochemical CO2 reduction is always accompanied by a competitive hydrogen evolution reaction as water is used as a hydrogen source. In addition to intrinsic activity control, geometrical factors of electrocatalysts such as porous structure have been demonstrated to affect the reaction selectivity, but understanding its origin is still important...
Solar-chemical production is one of the most promising options for producing valuable chemicals from greenhouse gases. An economically attractive and industrially applicable solar-chemical production device not only requires the catalyst and/or reactor design, but also the auxiliary unit process design, process integration, and optimization. Herein...
Metal-oxide interfaces provide a new opportunity to improve catalytic activity based on electronic and chemical interactions at the interface. Constructing high density of interfaces is essential in maximizing synergistic interactions. Here, we demonstrate that Cu/ceria interfaces made by sintering nanocrystals facilitate C-C coupling reactions in...
Recently, the electrochemical CO 2 reduction has been intensively researched for high selectivities and stabilities. The performance of electrochemical CO 2 reduction can be restricted by mass transfer limitation from the low concentration of CO 2(aq) . Therefore, CO 2 reduction systems with gas diffusion electrodes (GDE) have been suggested. CO 2...
In this study, we demonstrate the initial morphology of nanoparticles can be transformed into small fragmented na-noparticles, which were densely contacted to each other, during electrochemical CO2 reduction reaction (CO2RR). Cu-based nanoparticles were directly grown on a carbon support by using cysteamine immobilization agent, and the syn-thesize...
Catalytic activities of transition metal-doped IrO2 nanoparticles (TM-IrO2 NPs; TM = Cr, Mn, Fe, Co, or Ni) are compared for various oxidation reactions such as electrochemical oxygen evolution reaction (OER), gas-phase photo-oxidation of thiol function group, and CO oxidative conversion. Here, we discovered a series of TM-IrO2 catalysts have a com...
Oxygen-Cu (O-Cu) combination catalysts have recently achieved highly improved selectivity for ethylene production from the electrochemical CO2 reduction reaction (CO2RR). In this study, we developed anodized copper (AN-Cu) Cu(OH)2 catalysts by a simple electrochemical synthesis method and achieved ~40% Faradaic efficiency for ethylene production, a...
Water splitting is a clean and renewable way to produce hydrogen, and developing an efficient water oxidation electrocatalyst is crucial to overcome the slow kinetics and large overpotential of the oxygen evolution reaction (OER) in water electrolysis. In this work, we demonstrate that OER activity of an electrodeposited Ni catalyst can be influenc...
Modified carbon powders by doping are attractive electrocatalysts for chemical conversion due to its low cost and high activity. Here, we demonstrate that electrochemical CO2 to CO conversion activities in the aqueous media are enhanced by the transition metal incorporation in nitrogen-doped carbon (M-N/C; M=Fe, Co, Cu), and the type of the metals...
Here, we successfully synthesize Ta3N5 thin film using a simple metal-organic-precursor decomposition process followed by conversion to nitride and study its photoelectrochemical (PEC) properties to understand the charge separation on the surface. Newly synthesized Ta3N5 photoanodes showed a significant difference in the PEC activity in relation to...
An electron-mediated CO2-to-chemical conversion system is regarded as one of the effective solutions for the depletion of fossil fuels and the accumulation of atmospheric CO2. In this process, the protons and electrons generated from the water-oxidation reaction at an anode are used during reduction of CO2 at a cathode, in order to produce high-val...