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Decomposition of methylamine on Mo(100) surface: A DFT study

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Journal of Natural Gas Chemistry 2012年第2期21卷 132-137页

作者： Jianhong Liu Cunqin Lü Dongli Du Yong Guo College of Chemistry and Chemical Engineering Shanxi Datong UniversityDatong 037009ShanxiChina

The initial decomposition of methylamine on Mo（100） surface has been investigated by self-consistent （GGA-PW91） density functional theory combined with periodic slab model. The adsorption energies of possible species and the activation energies for possible elementary reactions involved are obtained in the present work. Our results indicate that the barriers decreased with the order of C-NN-HC-H. In addition, metastable adsorption of the abstracted hydrogen atom on the hollow site in the final state is also considered for the N-H and C-H bond breaking. For the C-H bond cleavage, the reaction barrier that the abstracted hydrogen located on the hollow site in the final state is lower than that on the bridge site. However, for the N H bond breaking, the barriers are alike for the abstracted hydrogen on both hollow and bridge sites in the final state.

关键词： methylamine decomposition Mo(100) DFT calculations slab model

Density Functional Theoretical Studies on the Methanol Adsorption and Decomposition on Ru（0001） Surfaces

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Chemical Research in Chinese Universities 2016年第2期32卷 234-241页

作者： LIU Jianhong LV Cunqin JIN Chun GUO Yong WANG Guichang College of Chemistry and Enviromental Engineering Shanxi Datong University Datong 037009 P. R. China Key Laboratory of Advanced Energy Materials Chemistry Ministry of Education Department of Chemistry Center of Theoretical Chemistry Study Nankai University Tianjin 300071 P. R. China

Periodic density functional theory（DFT） calculations are presented to describe the adsorption and decomposition of CH3OH on Ru（0001） surfaces with different coverages, including p（3 ×2）, p（2×2）, and p（2× 1） unit cells, corresponding to monolayer（ML） coverages of 1/6, 1/4, and 1/2, respectively. The geometries and energies of all species involved in methanol dissociation were analyzed, and the initial decomposition reactions of methanol and the subsequent dehydrogenations reactions of CH3O and CH2OH were all computed at 1/2, 1/4, and 1/6 ML coverage on the Ru（0001） surface. The results show that coverage exerts some effects on the stable adsorption of CH30, CH2OH, and CH3, that is, the lower the coverage, the stronger the adsorption. Coverage also exerts effects on the initial decomposition of methanol. C-H bond breakage is favored at 1/2 ML, whereas C-H and O--H bond cleavages are preferred at 1/4 and 1/6 ML on the Ru（0001） surface, respectively. At 1/4 ML coverage on the Ru（0001） surface, the overall reaction mechanism can be written as 9CH3OH ,3CH30＋6CH2OH＋9H ,6CH20＋3CHOH＋18H , 7CHO＋COH＋CH＋OH＋26H → 8CO＋C＋O＋36H.

关键词： Methanol decomposition Ru(0001) Coverage effect Density functional theory calculation slab model

The spatiotemporal variation of the wind-induced near-inertial energy flux in the mixed layer of the South China Sea

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Acta Oceanologica Sinica 2015年第1期34卷 66-72页

作者： LI Juan LIU Junliang CAI Shuqun PAN Jiayi State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of Sciences University of Chinese Academy of Sciences Institute of Earth and Space Information Science Chinese University of Hong Kong

On the basis of the QSCAT/NCEP blended wind data and simple ocean data assimilation(SODA), the wind-induced near-inertial energy flux(NIEF) in the mixed layer of the South China Sea(SCS) is estimated by a slab model, and the model results are verified by observational data near the Xisha Islands in the SCS. Then, the spatial and temporal variations of the NIEF in the SCS are analyzed. It is found that, the monthly mean NIEF exhibits obvious spatial and temporal variabilities, i.e., it is large west of Luzon Island all the year, east of the Indo-China Peninsula all the year except in spring, and in the northern SCS from May to September. The large monthly mean NIEF in the first two zones may be affected by the large local wind stress curl whilst that in the last zone is probably due to the shallow mixed layer depth. Moreover, the monthly mean NIEF is relatively large in summer and autumn due to the passage of typhoons. The spatial mean NIEF in the mixed layer of the SCS is estimated to be about 1.25 m W/m2 and the total wind energy input from wind is approximately 4.4 GW. Furthermore, the interannual variability of the spatial monthly mean NIEF and the Ni?o3.4 index are negatively correlated.

关键词： near-inertial energy flux mixed layer spatiotemporal variation slab model South China Sea

Simulation of wind-induced near-inertial oscillations in a mixed layer near the east coast of Korea in the East/Japan Sea

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Acta Oceanologica Sinica 2013年第9期32卷 11-20页

作者： NAM SungHyun PARK Young-Gyu Naval Systems Development Center Agency for Defense Development Ocean Circulation and Climate Research Division Korea Institute of Ocean Science and Technology

Using a simple damped slab model, it was possible to show that a local wind induced 88% （15 of 17） of the near-inertial oscillations （NIO） observed in the mixed layer near the east coast of Korea from 1999 to 2004. The model, however, overestimated the energy level in about two-thirds of the simulated cases, because the slab model was forced with winds whose characteristic period was shorter than the damping time scale of the model at 1.5 d. At the observation site, due to typhoons and orographic effects, high-frequency wind forcing is quite common, as is the overestimation of the energy level in the slab model results. In short, a simple slab model with a damping time-scale of about 1.5 d would be enough to show that the local wind was the main energy source of the near-inertial energy in this area, but the model could not be used to accurately estimate the amount of the work done by the wind to the mixed layer.

关键词： near-inertial oscillations near-inertial waves slab model high-frequency wind forcing eastcoast of Korea

A DFT Study of 2-Bromothiophene Adsorption on the Rh(111)Surface

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Chinese Journal of Structural Chemistry 2010年第7期29卷 1051-1060页

作者： CHEN Zhan-Hong DING Kai-Ning XU Xiang-Lan LI Jun-Jian Department of Information Technology Fujian Education College Fuzhou Fujian 350001 China Department of Chemistry Fuzhou University Fuzhou Fujian 350108 China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou Fujian 350002 China

Adsorption behaviors of 2-bromothiophene on the Rh（111） surface were discussed with DFT. The results revealed that adsorption at the parallel hol site and bridge site was the most stable. After adsorption, bond length of 2-bromothiophene changed significantly. Molecular plane was distorted, and C-H （Br, S） in the molecule was oblique and upswept against the metal surface. Vertical adsorption site was less stable than the plane adsorption site, but there was no distortion for the thiophene ring after adsorption. Aromaticity of 2-bromothiophene was destroyed at the hol and bridge adsorption sites, and the carbon atom in the thiophene ring presented quasi-sp3 hybfidizaton. After adsorption at the parallel hol, 2-bromothiophene obtained 0.86 electrons in total, and Rh（111） surface lost 2.08 electrons in all.

关键词： 2-bromothiophene Rh(111) DFT adsorption slab model

Insights into SO_2 and H_2O co-adsorption on Cu(100) surface with calculations of density functional theory

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Transactions of Nonferrous Metals Society of China 2015年第12期25卷 4102-4109页

作者：魏薪董超芳陈章华黄建业肖葵李晓刚北京科技大学新材料技术研究院腐蚀与防护中心北京100083 北京科技大学数理学院北京100083

The co-adsorption behaviors of SO2 and H2 O on face-centered cubic Cu（100） ideal surface were studied using the GGA-r PBE method of density functional theory（DFT） with slab models. The optimized structures of single H2 O and SO2 on Cu（100） surface were calculated at the coverage of 0.25 ML（molecular layer） and 0.5 ML. The results show that there was no obvious chemical adsorption of them on Cu（100） surface. The adsorbed structures, adsorption energy and electronic properties including difference charge density, valence charge density, Bader charge analysis and partial density of states（PDOS） of co-adsorbed structures of H2 O and SO2 were investigated to illustrate the interaction between adsorbates and surface. H2 O and SO2 can adsorb on surface of Cu atoms chemically via molecule form at the coverage of 0.25 ML, while H2 O dissociated into OH adsorbed on surface and H bonded with SO2 which keeps away from surface at the coverage of 0.5 ML.

关键词： SO2 H2O Cu density functional theory co-adsorption slab model adsorption energy charge transfer