Yun Jeong Hwang

Selective electrochemical reduction of CO2 is one of the most sought-after processes because of the potential to convert a harmful greenhouse gas to a useful chemical. We have discovered that immobilized Ag nanoparticles supported on carbon exhibit enhanced Faradaic efficiency and a lower overpotential for selective reduction of CO2 to CO. These electrocatalysts were synthesized directly on the carbon support by a facile one-pot method using a cysteamine anchoring agent resulting in controlled m

In this study, we demonstrate that the initial morphology of nanoparticles can be transformed into small fragmented nanoparticles, 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 synthesized nanoparticle catalyst showed increasing activity during initial CO₂RR, doubling Faradaic efficiency of C<sub>2</

Oxygen–Cu (O–Cu) combination catalysts have recently achieved highly improved selectivity for ethylene production from the electrochemical CO 2 reduction reaction (CO 2 RR). 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, and high stability over 40 h. Notably, the initial reduction conditions applied to AN-Cu were critical to achieving selective and stable ethylene p

There are currently great needs to develop low-cost inorganic materials that can efficiently perform solar water splitting as photoelectrolysis of water into hydrogen and oxygen has significant potential to provide clean energy. We investigate the Si/TiO(2) nanowire heterostructures to determine their potential for the photooxidation of water. We observed that highly dense Si/TiO(2) core/shell nanowire arrays enhanced the photocurrent by 2.5 times compared to planar Si/TiO(2) structure due to th

In real-time measurements, CO dimerization occurred concurrently with CO adsorption (∼5 s), while proton-coupled reduction toward *CHO has slower kinetics (∼30 s).

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 key performance parameters such as faradaic efficiency (FE), current density, and overpotential in the practical industrial-scale applications. Furtherm

We report that the length and surface properties of TiO(2) nanowires can have a dramatic effect on their photoelectrochemical properties. To study the length dependence, rutile TiO(2) nanowires (0.28-1.8 μm) were grown on FTO substrates with different reaction times (50-180 min) using a hydrothermal method. Nanowires show an increase in photocurrent with length, and a maximum photocurrent of 0.73 mA/cm(2) was measured (1.5 V vs RHE) for 1.8 μm long nanowires under AM 1.5G simulated sunlight illu

Electrochemical CO 2 conversion to chemical products is a promising strategy for sustainable industrial development. However, the success of this approach requires an in-depth understanding of catalysis because it involves highly complex multistep reactions. Herein, we suggest a rational design of a hierarchical Bi dendrite catalyst for an efficient conversion of CO 2 to formate. A high selectivity (∼89% at −0.74 V RHE ) and, more importantly, a stable performance during long-term operation (∼12

Abstract Electrochemical reduction of carbon dioxide (CO 2 RR) product distribution has been identified to be dependent on various surface factors, including the Cu facet, morphology, chemical states, doping, etc., which can alter the binding strength of key intermediates such as *CO and *OCCO during reduction. Therefore, in‐depth knowledge of the Cu catalyst surface and identification of the active species under reaction conditions aid in designing efficient Cu‐based electrocatalysts. This prog

The electrochemical CO 2 reduction reaction to form valued hydrocarbon molecules is an attractive process, because it can be coupled with renewable energy resources for carbon recycling. For an efficient CO 2 conversion, designing a catalyst with high activity and selectivity is crucial, because the CO 2 reduction reaction in aqueous media competes with the hydrogen evolution reaction (HER) intensely. We have developed a strategy to tune CO 2 reduction activity by modulating the binding energies

Three-dimensional hierarchical nanostructures were synthesized by the halide chemical vapor deposition of InGaN nanowires on Si wire arrays. Single phase InGaN nanowires grew vertically on the sidewalls of Si wires and acted as a high surface area photoanode for solar water splitting. Electrochemical measurements showed that the photocurrent density with hierarchical Si/InGaN nanowire arrays increased by 5 times compared to the photocurrent density with InGaN nanowire arrays grown on planar Si (

Recently, the WO 3 /BiVO 4 heterojunction has shown promising photoelectrochemical (PEC) water splitting activity based on its charge transfer and light absorption capability, and notable enhancement of the photocurrent has been achieved via morphological modification of WO 3 . We developed a graft copolymer-assisted protocol for the synthesis of WO 3 mesoporous thin films on a transparent conducting electrode, wherein the particle size, particle shape, and thickness of the WO 3 layer were contr

Here, we have developed porous nanostructured Zn electrocatalysts for CO 2 reduction reaction (CO 2 RR), fabricated by reducing electrodeposited ZnO (RE-Zn) to activate the CO 2 RR electrocatalytic performance. We discovered that the electrochemical activation environment using CO 2 -bubbled electrolyte during reducing ZnO in a pretreatment step is important for highly selective CO production over H 2 production, while using Ar gas bubbling instead can lead to less CO product of the Zn-based cat

Abstract The conversion of carbon dioxide (CO 2 ) to valuable fuels and chemicals offers a new pathway for sustainable and clean carbon fixation. Recently, the focus has been on electrochemical CO 2 reduction on heterogeneous electrode catalysts, leading to remarkable achievements in the reaction performance. To date, CO 2 to carbon monoxide (CO) conversion is considered as the most promising candidate reaction for the industrial market, owing to its high efficiency and reasonable technoeconomic

The direct conversion of low concentrations of CO2 is an essential approach, considering the expensive gas conditioning process for pure CO2, but has not yet been intensely studied in a membrane electrode assembly (MEA) electrolyzer. Herein, we explored the CO2 reduction with various CO2 concentrations in a zero-gap MEA electrolyzer and found that suppressing the hydrogen evolution reaction (HER) became more critical at low concentrations of CO2. We demonstrate that a Ni single-atom (Ni-N/C) cat