Jae Jeong Kim

Bio: Jae Jeong Kim is an academic researcher from Seoul National University. The author has contributed to research in topics: Catalysis & Chemical-mechanical planarization. The author has an hindex of 31, co-authored 238 publications receiving 3655 citations.

Electrodeposited Ni dendrites with high activity and durability for hydrogen evolution reaction in alkaline water electrolysis

Abstract: Different shapes of various nickel structures, including dendrite, particle and film are fabricated by electrodeposition under various conditions. The shape of nickel structures is definitely dependent on the deposition potential, leading to different electrochemical surface area and edge facets. The nickel particle which has a polycrystalline center and edge is obtained at high negative potential. On the other hand, the nickel dendrite deposited by relatively low negative potential exhibits large electrochemical surface area and a particularly active facet for hydrogen evolution reaction (HER) in alkaline water electrolysis. In fact the nickel dendrite shows the highest catalytic activity and stability for HER among the various nickel structures.

Electrodeposited Ag catalysts for the electrochemical reduction of CO2 to CO

Abstract: For the electrochemical reduction of CO2 to CO, a dendrite-type Ag catalyst was fabricated via an electrodeposition method in an ammonia-based Ag deposition solution containing ethylenediamine (EN) as an additive. The influence of electrodeposition parameters on the properties of this catalyst was examined and further correlated with CO production efficiency. The addition of EN changed the intensity ratio of (220) vs. (111) planes in the Ag catalyst, which was shown to be proportional to the CO production activity. Furthermore, EN modified the chemical shift of Ag3d5/2 in the negative direction, increasing the CO production efficiency. Under optimized deposition conditions (–0.45 V vs. Ag/AgCl, 40 mM EN), which were a compromise between intensity ratio and chemical shift, the fabricated Ag catalysts exhibited the highest Faradaic efficiency and mass activity for CO during CO2 electrolysis in 0.5 M KHCO3. The experimental correlation between CO production efficiency and the crystalline/electronic structures of the catalyst suggested guidelines for further improving the Ag catalyst activity.

Enhanced catalytic activity of electrodeposited Ni-Cu-P toward oxygen evolution reaction

Abstract: The slow kinetics of the oxygen evolution reaction (OER) and the high cost of the precious metal catalysts for the OER limit the efficiency and cost-effectiveness of water splitting. In this study, we introduce electrodeposited nickel-copper-phosphorous (NiCuP) as an efficient OER electrocatalyst in alkaline medium. The addition of Cu into the NiP electrocatalyst significantly enhanced the OER activity. Optimization of the electrodeposition conditions revealed that Ni59Cu19P9 in terms of atomic percent exhibited the best activity with a reduced Tafel slope and charge transfer resistance for the OER, compared to NiP. The Ni59Cu19P9 catalyst successfully endured the OER operation at 10 mA/cm2 for up to 30 h while maintaining a Faradaic efficiency of over 99%. The X-ray photoelectron spectroscopy showed that the amount of active Ni hydroxide (NiOOH) species increased with the addition of Cu, which likely contributed to the enhanced of catalytic activity.

Progress and Perspectives of Electrochemical CO2 Reduction on Copper in Aqueous Electrolyte

Abstract: To date, copper is the only heterogeneous catalyst that has shown a propensity to produce valuable hydrocarbons and alcohols, such as ethylene and ethanol, from electrochemical CO2 reduction (CO2R). There are variety of factors that impact CO2R activity and selectivity, including the catalyst surface structure, morphology, composition, the choice of electrolyte ions and pH, and the electrochemical cell design. Many of these factors are often intertwined, which can complicate catalyst discovery and design efforts. Here we take a broad and historical view of these different aspects and their complex interplay in CO2R catalysis on Cu, with the purpose of providing new insights, critical evaluations, and guidance to the field with regard to research directions and best practices. First, we describe the various experimental probes and complementary theoretical methods that have been used to discern the mechanisms by which products are formed, and next we present our current understanding of the complex reaction networks for CO2R on Cu. We then analyze two key methods that have been used in attempts to alter the activity and selectivity of Cu: nanostructuring and the formation of bimetallic electrodes. Finally, we offer some perspectives on the future outlook for electrochemical CO2R.

Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles.

Abstract: Hydrogen fuel is considered as the cleanest renewable resource and the primary alternative to fossil fuels for future energy supply. Sustainable hydrogen generation is the major prerequisite to realize future hydrogen economy. The electrocatalytic hydrogen evolution reaction (HER), as the vital step of water electrolysis to H2 production, has been the subject of extensive study over the past decades. In this comprehensive review, we first summarize the fundamentals of HER and review the recent state-of-the-art advances in the low-cost and high-performance catalysts based on noble and non-noble metals, as well as metal-free HER electrocatalysts. We systemically discuss the insights into the relationship among the catalytic activity, morphology, structure, composition, and synthetic method. Strategies for developing an effective catalyst, including increasing the intrinsic activity of active sites and/or increasing the number of active sites, are summarized and highlighted. Finally, the challenges, perspectives, and research directions of HER electrocatalysis are featured.

Cocatalysts for Selective Photoreduction of CO2 into Solar Fuels.

Abstract: Photoreduction of CO2 into sustainable and green solar fuels is generally believed to be an appealing solution to simultaneously overcome both environmental problems and energy crisis. The low selectivity of challenging multi-electron CO2 photoreduction reactions makes it one of the holy grails in heterogeneous photocatalysis. This Review highlights the important roles of cocatalysts in selective photocatalytic CO2 reduction into solar fuels using semiconductor catalysts. A special emphasis in this review is placed on the key role, design considerations and modification strategies of cocatalysts for CO2 photoreduction. Various cocatalysts, such as the biomimetic, metal-based, metal-free, and multifunctional ones, and their selectivity for CO2 photoreduction are summarized and discussed, along with the recent advances in this area. This Review provides useful information for the design of highly selective cocatalysts for photo(electro)reduction and electroreduction of CO2 and complements the existing reviews on various semiconductor photocatalysts.

Damascene copper electroplating for chip interconnections

Abstract: Damascene copper electroplating for on-chip interconnections, a process that we conceived and developed in the early 1990s, makes it possible to fill submicron trenches and vias with copper without creating a void or a seam and has thus proven superior to other technologies of copper deposition. We discuss here the relationship of additives in the plating bath to superfilling, the phenomenon that results in superconformal coverage, and we present a numerical model which accounts for the experimentally observed profile evolution of the plated metal.

Oleylamine in Nanoparticle Synthesis

Abstract: Wet chemistry in organic solvents has proven highly efficient for the preparation of several types of metallic, metal-oxide, and semiconductor nanostructures. This Short Review focuses on the use of oleylamine (OAm) as a versatile reagent for the synthesis of various nanoparticle systems. We describe the ability of OAm to act as a surfactant, solvent, and reducing agent, as a function of other synthesis parameters. We also discuss the specific role of OAm either alone or in combination with other reactants, to form nanostructures using a variety of organic or inorganic compounds as precursors. In certain cases OAm can form complex compounds with the metal ions of the corresponding precursor, leading to metastable compounds that can act as secondary precursors and thus be decomposed in a controlled way to yield nanoparticles. We also point out that OAm-stabilized particles can often be dispersed in different organic solvents yielding solutions with enhanced colloidal stability over long times and the poten...