SOOHYUN GO

JEONG-HEON KIM

DAEWON BAE

SEOLHA LIM

YUJIN LEE

JUNGSU EO

DONG-HYUN SHIN

HYEON-IL JEONG

YEON-A CHA

JINOH JUNG

SEO-JUNE PARK

GEON-WOO KIM

The Electrocatalytic Materials Laboratory (EML) at Korea University focuses on developing electrocatalysts for renewable energy conversion and energy storage. Research areas include electrochemical carbon dioxide reduction (CO2RR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER), carbon upgrading, and biomass conversion to produce value-added chemicals. The lab aims to address energy and environmental issues through multidisciplinary research in materials science & engineering and chemistry.

고려대학교 전기촉매 소재 연구실(Electrocatalytic Materials Laboratory, EML)은 재생 에너지 전환 및 에너지 저장을 위한 전기 촉매 개발에 중점을 둔다. 주요 연구 분야는 전기화학적 이산화탄소 환원 (CO2RR), 수소 발생 반응 (HER), 산소 발생 반응 (OER), 탄소 개질 및 바이오매스 전환을 통한 고에너지 밀도 화학 물질 생산이다. 재료 과학 및 공학, 화학 분야의 학제 간 연구를 통해 에너지 및 환경 문제 해결을 목표로 한다.

Advances in reactive carbon capture via carbonate/bicarbonate electrolysis for efficient CO 2 utilization

Controlling the Product Selectivity of CO2 Electroreduction via Gas Diffusion Electrode Design

Thermodynamic phase control of Cu–Sn alloy electrocatalysts for selective CO 2 reduction

Advancements in Understanding Catalyst Reconstruction During Electrochemical CO2 Reduction

CO 2 electrolysis to multicarbon products at activities greater than 1 A cm −2

Enhanced nitrate-to-ammonia activity on copper–nickel alloys via tuning of intermediate adsorption

Molecular tuning of CO2-to-ethylene conversion

Molecular enhancement of heterogeneous CO 2 reduction

Cooperative CO2-to-ethanol conversion via enriched intermediates at molecule–metal catalyst interfaces

Efficient electrically powered CO 2 -to-ethanol via suppression of deoxygenation

Binding site diversity promotes CO2 electroreduction to ethanol

Copper nanocavities confine intermediates for efficient electrosynthesis of C3 alcohol fuels from carbon monoxide

Metal-Organic Frameworks Mediate Cu Coordination for Selective CO2 Electroreduction

Chloride-mediated selective electrosynthesis of ethylene and propylene oxides at high current density

Hydroxide promotes carbon dioxide electroreduction to ethanol on copper via tuning of adsorbed hydrogen

Cascade surface modification of colloidal quantum dot inks enables efficient bulk homojunction photovoltaics

Electrochemical upgrade of CO 2 from amine capture solution

CO2 Electroreduction from Carbonate Electrolyte

Efficient Methane Electrosynthesis Enabled by Tuning Local CO 2 Availability

Defining a materials database for the design of copper binary alloy catalysts for electrochemical CO2 conversion

Quasi-graphitic carbon shell-induced Cu confinement promotes electrocatalytic CO 2 reduction toward C 2+ products

Tuning OH binding energy enables selective electrochemical oxidation of ethylene to ethylene glycol

A unifying mechanism for cation effect modulating C1 and C2 productions from CO 2 electroreduction

Copper/alkaline earth metal oxide interfaces for electrochemical CO 2 -to-alcohol conversion by selective hydrogenation

DAE-HYUN NAM

Electrolysis offers an attractive route to upgrade greenhouse gases such as carbon dioxide (CO 2 ) to valuable fuels and feedstocks; however, productivity is often limited by gas diffusion through a liquid electrolyte to the surface of the catalyst. Here, we present a catalyst:ionomer bulk heterojunction (CIBH) architecture that decouples gas, ion, and electron transport. The CIBH comprises a metal and a superfine ionomer layer with hydrophobic and hydrophilic functionalities that extend gas and ion transport from tens of nanometers to the micrometer scale. By applying this design strategy, we achieved CO 2 electroreduction on copper in 7 M potassium hydroxide electrolyte (pH ≈ 15) with an ethylene partial current density of 1.3 amperes per square centimeter at 45% cathodic energy efficiency.

Electrochemical conversion of nitrate (NO 3 – ) into ammonia (NH 3 ) recycles nitrogen and offers a route to the production of NH 3 , which is more valuable than dinitrogen gas. However, today’s development of NO 3 – electroreduction remains hindered by the lack of a mechanistic picture of how catalyst structure may be tuned to enhance catalytic activity. Here we demonstrate enhanced NO 3 – reduction reaction (NO 3 – RR) performance on Cu 50 Ni 50 alloy catalysts, including a 0.12 V upshift in the half-wave potential and a 6-fold increase in activity compared to those obtained with pure Cu at 0 V vs reversible hydrogen electrode (RHE). Ni alloying enables tuning of the Cu d- band center and modulates the adsorption energies of intermediates such as *NO 3 – , *NO 2 , and *NH 2 . Using density functional theory calculations, we identify a NO 3 – RR-to-NH 3 pathway and offer an adsorption energy–activity relationship for the …

The electrocatalytic reduction of carbon dioxide, powered by renewable electricity, to produce valuable fuels and feedstocks provides a sustainable and carbon-neutral approach to the storage of energy produced by intermittent renewable sources. However, the highly selective generation of economically desirable products such as ethylene from the carbon dioxide reduction reaction (CO 2 RR) remains a challenge. Tuning the stabilities of intermediates to favour a desired reaction pathway can improve selectivity , – , and this has recently been explored for the reaction on copper by controlling morphology, grain boundaries, facets, oxidation state and dopants. Unfortunately, the Faradaic efficiency for ethylene is still low in neutral media (60 per cent at a partial current density of 7 milliamperes per square centimetre in the best catalyst reported so far), resulting in a low energy efficiency. Here we present a molecular …

The electrocatalytic carbon dioxide reduction reaction (CO 2 RR) addresses the need for storage of renewable energy in valuable carbon-based fuels and feedstocks, yet challenges remain in the improvement of electrosynthesis pathways for highly selective hydrocarbon production. To improve catalysis further, it is of increasing interest to lever synergies between heterogeneous and homogeneous approaches. Organic molecules or metal complexes adjacent to heterogeneous active sites provide additional binding interactions that may tune the stability of intermediates, improving catalytic performance by increasing Faradaic efficiency (product selectivity), as well as decreasing overpotential. We offer a forward-looking perspective on molecularly enhanced heterogeneous catalysis for CO 2 RR. We discuss four categories of molecularly enhanced strategies: molecular-additive-modified heterogeneous catalysts …

Electrochemical conversion of CO 2 into liquid fuels, powered by renewable electricity, offers one means to address the need for the storage of intermittent renewable energy. Here we present a cooperative catalyst design of molecule–metal catalyst interfaces with the goal of producing a reaction-intermediate-rich local environment, which improves the electrosynthesis of ethanol from CO 2 and H 2 O. We implement the strategy by functionalizing the copper surface with a family of porphyrin-based metallic complexes that catalyse CO 2 to CO. Using density functional theory calculations, and in situ Raman and operando X-ray absorption spectroscopies, we find that the high concentration of local CO facilitates carbon–carbon coupling and steers the reaction pathway towards ethanol. We report a CO 2 -to-ethanol Faradaic efficiency of 41% and a partial current density of 124 mA cm −2 at −0.82 V versus the reversible …

The carbon dioxide electroreduction reaction (CO 2 RR) provides ways to produce ethanol but its Faradaic efficiency could be further improved, especially in CO 2 RR studies reported at a total current density exceeding 10 mA cm −2 . Here we report a class of catalysts that achieve an ethanol Faradaic efficiency of (52 ± 1)% and an ethanol cathodic energy efficiency of 31%. We exploit the fact that suppression of the deoxygenation of the intermediate HOCCH* to ethylene promotes ethanol production, and hence that confinement using capping layers having strong electron-donating ability on active catalysts promotes C–C coupling and increases the reaction energy of HOCCH* deoxygenation. Thus, we have developed an electrocatalyst with confined reaction volume by coating Cu catalysts with nitrogen-doped carbon. Spectroscopy suggests that the strong electron-donating ability and confinement of the …

The electrochemical reduction of CO 2 has seen many record-setting advances in C 2 productivity in recent years. However, the selectivity for ethanol, a globally significant commodity chemical, is still low compared to the selectivity for products such as ethylene. Here we introduce diverse binding sites to a Cu catalyst, an approach that destabilizes the ethylene reaction intermediates and thereby promotes ethanol production. We develop a bimetallic Ag/Cu catalyst that implements the proposed design toward an improved ethanol catalyst. It achieves a record Faradaic efficiency of 41% toward ethanol at 250 mA/cm 2 and −0.67 V vs RHE, leading to a cathodic-side (half-cell) energy efficiency of 24.7%. The new catalysts exhibit an in situ Raman spectrum, in the region associated with CO stretching, that is much broader than that of pure Cu controls, a finding we account for via the diversity of binding configurations …

The electrosynthesis of higher-order alcohols from carbon dioxide and carbon monoxide addresses the need for the long-term storage of renewable electricity; unfortunately, the present-day performance remains below what is needed for practical applications. Here we report a catalyst design strategy that promotes C3 formation via the nanoconfinement of C2 intermediates, and thereby promotes C2:C1 coupling inside a reactive nanocavity. We first employed finite-element method simulations to assess the potential for the retention and binding of C2 intermediates as a function of cavity structure. We then developed a method of synthesizing open Cu nanocavity structures with a tunable geometry via the electroreduction of Cu 2 O cavities formed through acidic etching. The nanocavities showed a morphology-driven shift in selectivity from C2 to C3 products during the carbon monoxide electroreduction, to reach a …

The electrochemical carbon dioxide reduction reaction (CO 2 RR) produces diverse chemical species. Cu clusters with a judiciously controlled surface coordination number (CN) provide active sites that simultaneously optimize selectivity, activity, and efficiency for CO 2 RR. Here we report a strategy involving metal–organic framework (MOF)-regulated Cu cluster formation that shifts CO 2 electroreduction toward multiple-carbon product generation. Specifically, we promoted undercoordinated sites during the formation of Cu clusters by controlling the structure of the Cu dimer, the precursor for Cu clusters. We distorted the symmetric paddle-wheel Cu dimer secondary building block of HKUST-1 to an asymmetric motif by separating adjacent benzene tricarboxylate moieties using thermal treatment. By varying materials processing conditions, we modulated the asymmetric local atomic structure, oxidation state and …

Chemicals manufacturing consumes large amounts of energy and is responsible for a substantial portion of global carbon emissions. Electrochemical systems that produce the desired compounds by using renewable electricity offer a route to lower carbon emissions in the chemicals sector. Ethylene oxide is among the world’s most abundantly produced commodity chemicals because of its importance in the plastics industry, notably for manufacturing polyesters and polyethylene terephthalates. We applied an extended heterogeneous:homogeneous interface, using chloride as a redox mediator at the anode, to facilitate the selective partial oxidation of ethylene to ethylene oxide. We achieved current densities of 1 ampere per square centimeter, Faradaic efficiencies of ~70%, and product specificities of ~97%. When run at 300 milliamperes per square centimeter for 100 hours, the system maintained a 71(±1 …

Producing liquid fuels such as ethanol from CO 2 , H 2 O, and renewable electricity offers a route to store sustainable energy. The search for efficient electrocatalysts for the CO 2 reduction reaction relies on tuning the adsorption strength of carbonaceous intermediates. Here, we report a complementary approach in which we utilize hydroxide and oxide doping of a catalyst surface to tune the adsorbed hydrogen on Cu. Density functional theory studies indicate that this doping accelerates water dissociation and changes the hydrogen adsorption energy on Cu. We synthesize and investigate a suite of metal-hydroxide-interface-doped-Cu catalysts, and find that the most efficient, Ce(OH) x -doped-Cu, exhibits an ethanol Faradaic efficiency of 43% and a partial current density of 128 mA cm −2 . Mechanistic studies, wherein we combine investigation of hydrogen evolution performance with the results of operando Raman …

Control over carrier type and doping levels in semiconductor materials is key for optoelectronic applications. In colloidal quantum dots (CQDs), these properties can be tuned by surface chemistry modification, but this has so far been accomplished at the expense of reduced surface passivation and compromised colloidal solubility; this has precluded the realization of advanced architectures such as CQD bulk homojunction solids. Here we introduce a cascade surface modification scheme that overcomes these limitations. This strategy provides control over doping and solubility and enables n -type and p -type CQD inks that are fully miscible in the same solvent with complete surface passivation. This enables the realization of homogeneous CQD bulk homojunction films that exhibit a 1.5 times increase in carrier diffusion length compared with the previous best CQD films. As a result, we demonstrate the highest power …

CO 2 capture technologies based on chemisorption present the potential to lower net emissions of CO 2 into the atmosphere. The electrochemical upgrade of captured CO 2 to value-added products would be particularly convenient. Here we find that this goal is curtailed when the adduct of the capture molecule with CO 2 fails to place the CO 2 sufficiently close to the site of the heterogeneous reaction. We investigate tailoring the electrochemical double layer to achieve the valorization of chemisorbed CO 2 in an aqueous monoethanolamine electrolyte. We reveal, using electrochemical studies and in situ surface-enhanced Raman spectroscopy, that a smaller double layer distance correlates with improved activity for CO 2 to CO from amine solutions. With the aid of an alkali cation and accelerated mass transport by system design—temperature and concentration—we demonstrate amine–CO 2 conversion to CO with 72 …

The process of CO 2 valorization—from capture of CO 2 to its electrochemical upgrade—requires significant inputs in each of the capture, upgrade, and separation steps. Here we report an electrolyzer that upgrades carbonate electrolyte from CO 2 capture solution to syngas, achieving 100% carbon utilization across the system. A bipolar membrane is used to produce proton in situ to facilitate CO 2 release at the membrane:catalyst interface from the carbonate solution. Using a Ag catalyst, we generate syngas at a 3:1 H 2 :CO ratio, and the product is not diluted by CO 2 at the gas outlet; we generate this pure syngas product stream at a current density of 150 mA/cm 2 and an energy efficiency of 35%. The carbonate-to-syngas system is stable under a continuous 145 h of catalytic operation. The work demonstrates the benefits of coupling CO 2 electrolysis with a CO 2 capture electrolyte on the path to practicable CO 2 …

The electroreduction of carbon dioxide (CO 2 RR) to valuable chemicals is a promising avenue for the storage of intermittent renewable electricity. Renewable methane, obtained via CO 2 RR using renewable electricity as energy input, has the potential to serve as a carbon-neutral fuel or chemical feedstock, and it is of particular interest in view of the well-established infrastructure for its storage, distribution, and utilization. However, CO 2 RR to methane still suffers from low selectivity at commercially relevant current densities (>100 mA cm –2 ). Density functional theory calculations herein reveal that lowering *CO 2 coverage on the Cu surface decreases the coverage of the *CO intermediate, and then this favors the protonation of *CO to *CHO, a key intermediate for methane generation, compared to the competing step, C–C coupling. We therefore pursue an experimental strategy wherein we control local CO 2 …

While Cu electrodes are a versatile material in the electrochemical production of desired hydrocarbon fuels, Cu binary alloy electrodes are recently proposed to further tune reaction directionality and, more importantly, overcome the intrinsic limitation of scaling relations. Despite encouraging empirical demonstrations of various Cu‐based metal alloy systems, the underlying principles of their outstanding performance are not fully addressed. In particular, possible phase segregation with concurrent composition changes, which is widely observed in the field of metallurgy, is not at all considered. Moreover, surface‐exposed metals can easily form oxide species, which is another pivotal factor that determines overall catalytic properties. Here, the understanding of Cu binary alloy catalysts for CO 2 reduction and recent progress in this field are discussed. From the viewpoint of the thermodynamic stability of the alloy …

For steady electroconversion to value-added chemical products with high efficiency, electrocatalyst reconstruction during electrochemical reactions is a critical issue in catalyst design strategies. Here, we report a reconstruction-immunized catalyst system in which Cu nanoparticles are protected by a quasi-graphitic C shell. This C shell epitaxially grew on Cu with quasi-graphitic bonding via a gas–solid reaction governed by the CO (g) - CO 2 (g) - C (s) equilibrium. The quasi-graphitic C shell-coated Cu was stable during the CO 2 reduction reaction and provided a platform for rational material design. C 2+ product selectivity could be additionally improved by doping p -block elements. These elements modulated the electronic structure of the Cu surface and its binding properties, which can affect the intermediate binding and CO dimerization barrier. B-modified Cu attained a 68.1% Faradaic efficiency for C 2 H 4 at −0.55 …

There is significant interest in developing efficient electrochemical processes for commodity chemical manufacturing, all directly powered by renewable electricity. A vital chemical is ethylene glycol, with an annual consumption of around 20 million tonnes due to its use as antifreeze and as a polymer precursor. Here we report a one-step electrochemical route at ambient temperature and pressure in aqueous media to the selective partial oxidation of ethylene to ethylene glycol. Tuning of the catalyst OH binding energy was hypothesized to be crucial for facilitating the transfer of OH to *C 2 H 4 OH to form ethylene glycol. Computational studies suggested that a gold-doped palladium catalyst could perform this step efficiently, and experimentally we found it to exhibit an approximate 80% Faradaic efficiency to ethylene glycol, retaining its performance for 100 hours of continuous operation. These findings represent a …

Electrocatalysis, whose reaction venue locates at the catalyst–electrolyte interface, is controlled by the electron transfer across the electric double layer, envisaging a mechanistic link between the electron transfer rate and the electric double layer structure. A fine example is in the CO 2 reduction reaction, of which rate shows a strong dependence on the alkali metal cation (M + ) identity, but there is yet to be a unified molecular picture for that. Using quantum-mechanics-based atom-scale simulation, we herein scrutinize the M + -coupling capability to possible intermediates, and establish H + - and M + -associated ET mechanisms for CH 4 and CO/C 2 H 4 formations, respectively. These theoretical scenarios are successfully underpinned by Nernstian shifts of polarization curves with the H + or M + concentrations and the first-order kinetics of CO/C 2 H 4 formation on the electrode surface charge density. Our finding further …

Multicarbon alcohols produced by electrochemical CO 2 reduction (CO 2 RR) are attractive alternatives to fossil fuels; however, the selectivity towards alcohols in CO 2 RR remains low, a result of competing hydrocarbon (that is, ethylene) production. Here we report on Cu catalysts decorated with different alkaline earth metal oxides (MOs). We found that BaO delivers a Faradaic efficiency of 61% towards C 2+ alcohols. At an industry-relevant current density of 400 mA cm −2 , the ratio of alcohols to hydrocarbon reached 3:1. Mechanistic studies, including in operando X-ray absorption spectroscopy, in situ Raman spectroscopy and density functional theory calculations, suggested that the increased selectivity towards alcohols originates from sites at the MO/Cu interface. Furthermore, computational studies indicated that the incorporation of MOs favours a hydroxy-containing C 2 intermediate (*HCCHOH) over the …

Dae-Hyun Nam Group

교수님 소개

남대현

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Advances in reactive carbon capture via carbonate/bicarbonate electrolysis for efficient CO 2 utilization

Controlling the Product Selectivity of CO2 Electroreduction via Gas Diffusion Electrode Design

Advancements in Understanding Catalyst Reconstruction During Electrochemical CO2 Reduction

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

남대현

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Advances in reactive carbon capture via carbonate/bicarbonate electrolysis for efficient CO 2 utilization

Controlling the Product Selectivity of CO2 Electroreduction via Gas Diffusion Electrode Design

Advancements in Understanding Catalyst Reconstruction During Electrochemical CO2 Reduction

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집