Sang Uck Lee

A systematic analysis of electron transport characteristics for 1D heterojunctions with two nitrogen-doped (N-doped) capped carbon nanotubes (CNTs) facing one another at different conformations is presented considering the chirality of CNTs (armchair(5,5) and zigzag(9,0)) and spatial arrangement of N-dopants. The results show that the modification of the molecular orbitals by the N-dopants generates a conducting channel in the designed CNT junctions, inducing a negative differential resistance (

Despite the considerable efforts in advancing nonprecious-metal candidates as oxygen evolution reaction (OER) electrocatalysts, cost-effective production of efficient and stable catalysts via simple synthesis routes remains to be realized. We report on the experimental and density functional theory (DFT) guidelines of nickel (Ni)–vanadium (V) layered double hydroxides (LDHs) to prepare an optimal electrocatalyst by changing its composition ratio. The optimized Ni0.75V0.25 LDH exhibits the ultral

Introducing amorphous and ultrathin nanosheets of transition bimetal phosphate arrays that are highly active in the oxygen evolution reaction (OER) as shells over an electronically modulated crystalline core with low hydrogen absorption energy for an excellent hydrogen evolution reaction (HER) can boost the sluggish kinetics of the OER and HER in alkaline electrolytes. Therefore, in this study, ultrathin and amorphous cobalt-nickel-phosphate (CoNiPO_x ) nanosheet arrays are deposited o

A high performance B₃S monolayer for LIB anode material with high storage capacity, low OCV and low Li diffusion energy barrier.

We have systematically investigated a metal-free bifunctional electrocatalyst of heteroatom-doped carbon nitride (XY-C3N4, where X and Y indicate the dopant and doping site on C3N4, respectively) for oxygen evolution and oxygen reduction reactions (OER and ORR), considering the possible reaction pathways based on the Eley–Rideal (ER) mechanism as well as the doping effects on electrocatalytic activity. In this work, the relative stability of O* and OOH* intermediates was a key factor in determin

A series of [(C^N)2 Ir(acac)] complexes [{5-(2-R-CB)ppy}2 Ir(acac)] (3 a-3 g; acac=acetylacetonate, CB=o-carboran-1-yl, ppy=2-phenylpyridine; R=H (3 a), Me (3 b), iPr (3 c), iBu (3 d), Ph (3 e), CF3 C6 H4 (3 f), C6 F5 (3 g)) with various 2-R-substituted o-carboranes at the 5-position in the phenyl ring of the ppy ligand were prepared. X-ray diffraction studies revealed that the carboranyl CC bond length increases with increasing steric and electron-withdrawing effects from the 2-R substituents.

The facile synthesis of efficient non-precious-metal-based bifunctional catalysts for overall water splitting is highly desirable from both industrial and environmental perspectives. This study reports the electrodeposition and characterization of a transition-metal (Mo, Fe)-codoped nickel phosphide (Ni3P:FeMo) bifunctional catalyst for enhanced overall water splitting in an alkaline medium. The Ni3P:FeMo catalyst exhibited outstanding electrocatalytic performance for both the hydrogen evolution

Ni x Fe y Mo z layered double hydroxide (LDH) electrocatalysts fabricated via a simple hydrothermal technique for overall water splitting in an alkaline medium are reported.

The progress of ecofriendly, clean, and sustainable energy resources always demands suitable anode materials for batteries with high structural stability and superior storage capacity. Herein, we use density functional theory predictions to examine the potential features of newly proposed planar membranes consist of 5-, 6- and 8- membered carbon rings, named as α- and β-phographene (PhoG). Our calculations disclose that both α- and β-PhoG structures possess high structural, thermal, and mechanic

A fundamental understanding of the thermomechanical properties of electrode materials and Li-ion diffusion kinetics is indispensable for designing high-performance Li-ion batteries (LIBs) with high structural stability and safety. Herein, we performed both molecular dynamics (MD) simulations and density functional theory (DFT) calculations to investigate the thermomechanical properties and Li diffusion kinetics in a two-dimensional (2D) defect-filled graphene-like membrane consisting of 5-, 6-,