Sung Jong Yoo

Edge-exposed MoS2 nano-assembled structures are designed for high hydrogen evolution reaction activity and long term stability. The number of sulfur edge sites of nano-assembled spheres and sheets is confirmed by Raman spectroscopy and EXAFS analysis. By controlling the MoS2 morphology with the formation of nano-assembled spheres with the assembly of small-size fragments of MoS2, the resulting assembled spheres have high electrocatalytic HER activity and high thermodynamic stability.

A novel design concept of a three-dimensional graphene shell encapsulated cobalt nanostructure as a new route to tune the work function of graphene for enhanced ORR.

Pt impregnated into the RuO 2 phase assisted by oxophilic Co suppresses the over-oxidation of Ru during water electrooxidation under acidic conditions.

Abstract Nonprecious metals are promising catalysts to avoid the sluggish oxygen reduction reaction (ORR) in next‐generation regenerative fuel cells or metal–air batteries. Therefore, development of nonprecious metal catalysts for ORR is highly desirable. Herein, precise tuning of the atomic ratio of Fe and Co encapsulated in melamine‐derived nitrogen‐rich graphitic tube (NGT) is reported. The Co 1.08 Fe 3.34 hybrid with metalnitrogen bonds ( 1 : Co 1.08 Fe 3.34 @NGT) shows remarkable ORR catal

Structure effects of NiS and Ni3S2 nanoparticles were investigated for their electrocatalytic activity in the hydrogen evolution reaction in both acid and alkaline media. Owing to the different atomic configurations and crystalline structures, there is a hydrogen adsorption energy difference, which induces a difference in the activity. From density functional theory calculations and experimental observations, the importance of designing an electrocatalyst with an appropriate atomic configuration

We report Pt-based alloys with early transition metals. Significant electrocatalysis occurs during oxygen reduction reaction (ORR) at the Pt-Y alloy electrodes, and the extent depends on the alloy composition. The Pt-Y alloy electrode activity is related to the d-band center position, and the lattice strain and stability for oxygen reduction reaction.

The authors prepared uniformly shaped WO2.72 nanowire bundles using the solvothermal synthesis method. They investigated the potential of the WO2.72 nanowire bundles to be used as a cathode electrode for electrochromic devices and the effect of the Li+ insertion (or extraction) kinetics and diffusion of Li+. An electrode consisting of arrays of WO2.72 nanowire bundles was formed and used in an experiment using the Langmuir-Blodgett technique. The one-dimensional nanostructure of WO2.72 has a hig

The design of polymer electrolyte fuel cell electrocatalysts depends on two equally important fundamental principles: the optimization of electrocatalytic activities as well as the long-term stability under operating conditions (e.g., pH < 1 and E > 0.8 V). Pt-based alloys with transition metals (i.e., Pt–La) address both of these key issues. The oxygen reduction kinetics depends on the alloy composition which, in turn, is related to the d-band center position. The stability of the oxygen reduct

This paper reviews the energy efficiency of optical-packet-switching (OPS) systems in comparison with electronic packet switching and hybrid packet switching in the context of future networks. The paper will first discuss the energy efficiency metrics that should include considerations for life-cycle analysis, applications, and network-wide goodput. The state-of-the-art electronic packet switching router is currently energy-limited in scalability as it is difficult to implement a router with mor

The development of low-cost, high-efficiency electrocatalysts is of primary importance for hydrogen energy technology. Noble metal-based catalysts have been extensively studied for decades; however, activity and durability issues still remain a challenge. In recent years, carbon shell-encapsulated metal (M@C) catalysts have drawn great attention as novel materials for water electrolysis and fuel cell applications. These electrochemical reactions are governed mainly by interfacial charge transfer

Size-controlled Pt nanocatalysts embedded in TiO(2) were successfully synthesized by simultaneous dual-gun sputtering and were found to exhibit unique electronic properties depending on their size, which affected the potential of zero total charge, CO-bulk oxidation, and methanol oxidation reaction.

Despite breakthroughs in the activity of electrocatalysts for the oxygen reduction reaction (ORR), the development of nanoscale ORR electrocatalysts is still hindered by their instability. Here, to bridge the functional link between activity and stability, well-controlled Au@Pt (core@shell) nanoparticles are investigated. In situ monitoring of atomic dissolution and physicochemical analysis in conjunction with theoretical calculations reveal that the atomic-level stability of Au@Pt nanoparticle