Jeung Ku Kang

Postsynthetic exchange (PSE) of Ti(IV) into a Zr(IV)-based MOF enabled photocatalytic CO2 reduction to HCOOH under visible light irradiation with the aid of BNAH and TEOA. Use of a mixed-ligand strategy enhanced the photocatalytic activity of the MOF by introducing new energy levels in the band structure of the MOF.

Highly efficient electrochemical nitrate reduction could be key for sustainable ammonia production. Our NiFe LDH/Cu foam electrode exhibits an NH 3 selectivity of 95.8% with 98.5% nitrate conversion.

We present a new hybrid density-functional method which predicts transition state barriers with the same accuracy as CBS-APNO, and transition state barriers and enthalpies of reaction with smaller errors than B3LYP, BHandHLYP, and G2. The accuracy of the new method is demonstrated on 132 energies, including 74 transition state barriers and 58 enthalpies of reaction. For 40 reactions with reliable experimental barriers, the absolute mean deviations of the transition state barriers are 0.9, 1.0, 3

Vanadium pentoxide (V2O5) has received considerable attention as a lithium battery cathode because its specific capacity (>250 mA h g−1) is higher than those (<170 mA h g−1) of most commercial cathode materials. Despite this conspicuous advantage, V2O5 has suffered from limited cycle life, typically below a couple of hundred cycles due to the agglomeration of its particles. Once V2O5 particles are agglomerated, the insulating phases continuously expand to an extent that ionic and electronic cond

Here, we have synthesized the new titanium-embedded layered double hydroxides (LDHs), such as (Ni/Ti)LDH and (Cu/Ti)LDH. First of all, the formation of LDH structures and the bonding nature for a mixed oxide structure of LDHs are explored in this work. Also, it is determined that our LDHs show two absorption bands in the red and blue regions under visible light, thus different from those of a pure titanium oxide with absorption bands in only the UV region. We find that the (Ni/Ti)LDH with the hi

Highly porous gallium oxide was synthesized by reconstructing its surface and body with mesopores and macropores. For the first time, the efficient photocatalytic conversion of CO2 into a high energy carrier, CH4, using the porous gallium oxide was realized without any co-particle or sacrificial reagent. The enhanced photocatalytic activity is mainly attributed to the 300% higher CO2 adsorption capacity, as well as the 200% increased surface area, compared to the bulk nanoparticles. Furthermore,

Quantum chemistry is used to investigate the HF/H2O chemical etching mechanism of silicon dioxide. Etching proceeds through four sequential steps to remove silicon as SiF4(g) for silicon dioxide, eventually leading to a fluorine-terminated silicon surface which HF attacks, resulting in a hydrogen-passivated silicon surface. Our predicted activation barriers show that the concerted attack by HF and H2O enhances the etch rate over etching by HF alone by reducing the barrier for each etching step.

Metal-organic frameworks (MOFs) with isolated metal-monocatecholato groups have been synthesized via postsynthetic exchange (PSE) for CO2 reduction photocatalyst under visible light irradiation in the presence of 1-benzyl-1,4-dihydronicotinamide and triethanolamine. The Cr-monocatecholato species are more efficient than the Ga-monocatecholato species.

We report electrochemical performance of a TiO₂ combined with a nitrogen-doped open channeled graphene anode composite for sodium ion batteries.

Metal-organic frameworks (MOFs) have recently received much attention as promising candidates for gas storage, chemical separation, and heterogeneous catalysis. However, the applicability of MOFs remains limited due to their relatively large band gaps. Here, on the basis of first-principles theory study, it is demonstrated that this problem could be overcome by tailoring Zn2+ ions in MOFs with Co2+ ions while maintaining the same organic linkers. Density of states and molecular orbitals for MOFs

Nickel oxide-encapsulated hollow carbon nitride spheres with multiporosity show an ∼250% enhancement in capacitance, in addition to their robust cycle life.

First-principles calculation and x-ray diffraction simulation methods have been used to explore crystal structures and reaction mechanisms of the intermediate phases involved in dehydriding of LiBH4. LiBH4 was found to dehydride via two sequential steps: first dehydriding through LiBH, followed by the dehydriding of LiBH through LiB. The first step, which releases 13.1wt.% hydrogen, was calculated to have an activation barrier of 2.33eV per formula unit and was endothermic by 1.28eV per formula

We report a facile route to synthesize size tunable Fe(3)O(4) nanoparticles (NPs)-carbon nitride nanotube (CNNT) hybrids. These hybrids showing the water-soluble property are proven to exhibit ultra high peroxidase mimetic activity compared to those of pure NPs, where a colorless peroxidase substrate 3,3,5,5-tetramethylbenzidine changes by H(2)O(2) to its blue colored oxidized state.

Abstract Hybrid lithium‐ion energy storage devices are promising for future applications, but their anodes and cathodes still have structural limitations, for example, accommodating rich cationic/anionic reactions, rapid charge movement, and long cycle life. Herein, high‐capacity/high‐rate anode and cathode structures are developed to overcome these challenges. Molybdenum oxide (MoO 2 )‐implanted carbon frameworks making conductive carbon bonds with reduced graphene oxide (rGO) shells are develo

We use density functional theory to investigate atomic layer deposition (ALD) mechanism of silicon dioxide on the Si(100)-2×1 surface from the precursors SiCl4 and H2O. First, we explore the reaction mechanism of water with the bare Si(100)-2×1 surface to produce surface hydroxyl groups. We find that this reaction proceeds through a two-step pathway with an overall barrier of 33.3 kcal/mol. Next, we investigate the ALD mechanism for the binary reaction sequence: the SiCl4 half reaction and the H