The Role of Nanostructural Chemistry in the Design of Solid Catalysts

We report here the results of molecular dynamics and quantum chemical calculations on porous catalysts and supported metal catalysts to bring out the catalytic role played by nanostructures. We present three case studies where the computer simulation techniques have revealed the important structural aspects involved in the catalyst design. The role of exchanged metal cations in zeolite A for the molecular sieving of nitrogen and oxygen, controlled pore opening of hydrated VPI-5 by careful removal of water and the behavior of palladium metal particles supported over MgO are explained

Molecular dynamics simulation on a layer-by-layer homoepitaxial growth process of SrTiO3(001)

科研費報告書収録論文(課題番号:09355030・基盤研究(A)(2)・H9～H11/研究代表者:宮本, 明/次世代エレクトロニクス材料としての酸化物人口超格子の原子レベル設計と開発

Layer-by-layer heteroepitaxial growth process of a BaO layer on SrTiO3(001) as investigated by molecular dynamics

科研費報告書収録論文(課題番号:09355030・基盤研究(A)(2)・H9～H11/研究代表者:宮本, 明/次世代エレクトロニクス材料としての酸化物人口超格子の原子レベル設計と開発

Layer-by-layer homoepitaxial growth process of MgO(001)as investigated by molecular dynamics, density functional theory,and computer graphics

科研費報告書収録論文(課題番号:09355030・基盤研究(A)(2)・H9～H11/研究代表者:宮本, 明/次世代エレクトロニクス材料としての酸化物人口超格子の原子レベル設計と開発

Molecular dynamics simulation of enhanced oxygen ion diffusion in strained yttria-stabilized zirconia

科研費報告書収録論文(課題番号:09355030・基盤研究(A)(2)・H9～H11/研究代表者:宮本, 明/次世代エレクトロニクス材料としての酸化物人口超格子の原子レベル設計と開発

Quantum chemical study on the oxidation process of a hydrogen terminated Si surface

科研費報告書収録論文(課題番号:09450296・基盤研究(B)(2)・H9～H10/研究代表者:宮本, 明/新しい高速化第一原理分子動力学計算プログラムの開発と金属超微粒子触媒への応用

Diamond-like carbon coating under oleic acid lubrication: Evidence for graphene oxide formation in superlow friction

International audienceThe achievement of the superlubricity regime, with a friction coefficient below 0.01, is the Holy Grail of many tribological applications, with the potential to have a remarkable impact on economic and environmental issues. Based on a combined high-resolution photoemission and soft X-ray absorption study, we report that superlubricity can be realized for engineering applications in bearing steel coated with ultra-smooth tetrahedral amorphous carbon (ta-C) under oleic acid lubrication. The results show that tribochemical reactions promoted by the oil lubrication generate strong structural changes in the carbon hybridization of the ta-C hydrogen-free carbon, with initially high sp 3 content. Interestingly, the macroscopic superlow friction regime of moving mechanical assemblies coated with ta-C can be attributed to a few partially oxidized graphene-like sheets, with a thickness of not more than 1 nm, formed at the surface inside the wear scar. The sp 2 planar carbon and oxygen-derived species are the hallmark of these mesoscopic surface structures created on top of colliding asperities as a result of the tribochemical reactions induced by the oleic acid lubrication. Atomistic simulations elucidate the tribo-formation of such graphene-like structures, providing the link between the overall atomistic mechanism and the macroscopic experimental observations of green superlubricity in the investigated ta-C/oleic acid tribological systems

Does Metabolism of (S)-N-[1-(3-Morpholin-4-ylphenyl)ethyl]-3-phenylacrylamide Occur at the Morpholine Ring? Quantum Mechanical and Molecular Dynamics Studies

The mechanism of Cytochrome P450 3A4 mediated metabolism of (S)-N- [1-(3-morpholin-4ylphenyl)ethyl]-3-phenylacrylamide and its difluoro analogue have been investigated by density functional QM calculations aided with molecular mechanics/molecular dynamics simulations. In this article, we mainly focus on the metabolism of the morpholine ring of substrates 1 and 2. The reaction proceeds via a hydrogen atom abstraction from the morpholine ring by Compound I on a doublet potential energy surface. A transition state was observed at an O-H distance of 1.46 Å for 1 while 1.38 Å for 2. Transition state for the rebound mechanism was not observed. The energy barrier for the hydrogen atom abstraction from 1 was found to be 7.01 kcal/mol in gas phase while 19.53 kcal/mol when the protein environment was emulated by COSMO. Similarly the energy barrier for substrate 2 was found to be 11.07 kcal/mol in gas phase while it was reduced to 12.99 kcal/mol in protein environment. Our previous study reported energy barriers for phenyl hydroxylation of 7.4 kcal/mol. Large energy barriers for morpholine hydroxylation indicates that hydroxylation at the phenyl ring may be preferred over morpholine. MD simulations in protein environment indicated that hydrogen atom at C4 position of phenyl ring remains in closer proximity to oxyferryl oxygen of the heme moiety as compared to morpholine hydrogen and hence greater chance to metabolize at phenyl ring