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397 results on '"Xiao, Dequan"'

3. Thermomechanical properties of polypropylene and styrene-ethylene-butylene-styrene blends: a molecular simulation and experimental study

Author

Pokharel, Pashupati, Wei, Feng, Shi, Jianyi, Wang, Yingmin, and Xiao, Dequan

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

Polymer blends consisting of two or more polymers are important for a wide variety of industries and processes, but, the precise mechanism of their thermomechanical behaviour is incompletely understood. In order to understand clearly, it is essential to determine the miscibility and interactions between the components in polymer blend and its macroscopic thermomechanical properties. In this study, we performed experiments on SEBS and isotactic PP blends (SP) as well as molecular dynamics simulations, aiming to know the role played by molecular interactions on the thermomechanical properties. To investigate the glass transition temperature (Tg) of SEBS, PP and their blends at different ratio, the unit cell of the polymer molecular structure of each was established. The LAMMPS molecular dynamics method was used to predict the density, specific volume, free volume, enthalpy, kinetic energy, potential energy and bond energy. The (Tg) s of the SEBS, PP and SP blends were predicted by analysing these properties. Interestingly, the simulated values of the Tg of SEBS, PP and their blends showed good agreement with our experimental results obtained from dynamic mechanical analysis (DMA). This technique used in this work can be used in studying glass transition of other complex polymer blends., Comment: 32 Pages, 11 figures

Published
2021

4. Load and Energy Balance Strategy of SDN Control Plane in Mobility Scenarios

Author

Zhang, Fuwei, Ma, Wenwen, Xiao, Dequan, Peng, Hongyu, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Sun, Jiande, editor, Wang, Yue, editor, Huo, Mengyao, editor, and Xu, Lexi, editor

Published
2023
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16. The role of atomic orbitals of doped earth-abundant metals on designed copper catalytic surfaces

Author

Xiao, Dequan and Callahan, Trevor

Subjects
Condensed Matter - Materials Science
Abstract

It is a general challenge to design highly active or selective earth-abundant metals for catalytic hydrogenation. Here, we demonstrated an effective computational approach based on inverse molecular design theory to deterministically search for optimal binding sites on Cu (100) surface through the doping of Fe and/or Zn, and a stable Zn-doped Cu (100) surface was found with minimal binding energy to H-atoms. We analyze the electronic structure cause of the optimal binding sites using a new quantum chemistry method called orbital-specific binding energy analysis. Compared to the 3d-orbitals of surface Cu atoms, the 3d-orbitals of surface Zn-atoms show less binding energy contribution and participation, and are much less influenced by the electronic couplings of the media Cu atoms. Our study provides valuable green chemistry insights on designing catalysts using earth-abundant metals, and may lead to the development of novel Cu-based earth-abundant alloys for important catalytic hydrogenation applications such as lignin degradation or CO2 transformation., Comment: 8 pages, 6 figures

Published
2017
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35. Novel polymer nanocomposite composed of organic nanoparticles via self-assembly

Author

Xiao, Dequan, Lin, Kunhua, Fu, Qiang, and Yin, Qinjian

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

We report a novel class of polymer nanocomposite composed of organic nanoparticles dispersed in polymer matrix, with the particle sizes of 30-120 nm in radius. The organic nanoparticles were formed by the self-assembly of protonated poly(4-vinyl-pyridine)-r-poly(acrylonitrile) and amphiphilic metanil yellow dye molecules through electrostatic interactions in aqueous solution. A strongly broadened Raman shift band was probed, suggesting the presence of enhanced optoelectronic property from the polymer nanocomposite. Here, using random-copolymer polyelectrolytes and mesogenic amphiphiles as the designed building blocks for self-assembly, a new approach is acutally provided to fabricate organic nanoparticles., Comment: 12 pages, 5 figures

Published
2009

43. The Impact of Surface Chemistry and Synthesis Conditions on the Adsorption of Antibiotics onto MXene Membranes.

Author

Afolabi, Moyosore A., Xiao, Dequan, and Chen, Yongsheng

Subjects
*SURFACE chemistry, *ADSORPTION (Chemistry), *DENSITY functional theory, *HYDROGEN bonding interactions, *ANTIBIOTICS, *HYDROFLUORIC acid
Abstract

MXene, a two-dimensional (2D) nanomaterial with diverse applications, has gained significant attention due to its 2D lamellar structure, abundance of surface groups, and conductivity. Despite various established synthesis methods since its discovery in 2011, MXenes produced through different approaches exhibit variations in structural and physicochemical characteristics, impacting their suitability for environmental application. This study delves into the effect of synthesis conditions on MXene properties and its adsorption capabilities for four commonly prescribed antibiotics. We utilized material characterization techniques to differentiate MXenes synthesized using three prevalent etchants: hydrofluoric acid (HF), mixed acids (HCl/HF), and fluoride salts (LiF/HCl). Our investigation of adsorption performance included isotherm and kinetic analysis, complemented by density functional theory calculations. The results of this research pinpointed LiF/HCl as an efficient etchant, yielding MXene with favorable morphology and surface chemistry. Electrostatic interactions and hydrogen bonding between MXene surface terminations and ionizable moieties of the antibiotic molecules emerge as pivotal factors in adsorption. Specifically, a higher presence of oxygen terminations increases the binding affinities. These findings provide valuable guidance for etchant selection in environmental applications and underscore the potential to tailor MXenes through synthesis conditions to design membranes capable of selectively removing antibiotics and other targeted substances. [ABSTRACT FROM AUTHOR]

Published
2024
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45. High-Density Coordinatively Unsaturated Zn Catalyst for Efficient Alkane Dehydrogenation

Author

Wang, Linlin, Wang, Hui, Cheng, Renfei, Wang, Maolin, Cai, Xiangbin, Ren, Pengju, Xiao, Dequan, Wang, Ning, Wen, Xiao-Dong, Diao, Jiangyong, Wang, Xiaohui, Ma, Ding, Liu, Hongyang, Wang, Linlin, Wang, Hui, Cheng, Renfei, Wang, Maolin, Cai, Xiangbin, Ren, Pengju, Xiao, Dequan, Wang, Ning, Wen, Xiao-Dong, Diao, Jiangyong, Wang, Xiaohui, Ma, Ding, and Liu, Hongyang

Abstract

The exploration of non-noble metal catalysts for alkane dehydrogenation and their catalytic mechanisms is the priority in catalysis research. Here, we report a high-density coordinatively unsaturated Zn cation (Zn-cus) catalyst for the direct dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). The catalyst demonstrated good catalytic performance (similar to 40% initial EB conversion rate and >98% ST selectivity) and excellent regeneration ability in the reaction, which is attributed to the high-density (HD) distribution and high-stability structure of Zn-cus active sites on the surface of zinc silicate (HD-Zn-cus@ZS). Density functional theory (DFT) calculations further illustrated the reaction pathway and intermediates, supporting that the Zn-cus sites can efficiently activate the C-H bond of ethyl on ethylbenzene. Developing the high-density Zn-cus catalyst and exploring the catalytic mechanism laid a good foundation for designing practical non-noble metal catalysts.

Published
2023

46. Atomic-Dispersed Rh Enables Efficient Catalytic Nitrile Hydrogenation: Size Effect and Metal-Dependent Effect

Author

Chen, Jiawei, Jiao, Yueyue, Qin, Xuetao, Cai, Xiangbin, Wang, Maolin, Diao, Jiangyong, Wang, Linlin, Li, Chengyu, Ren, Pengju, Wen, Xiaodong, Wang, Ning, Rong, Junfeng, Xiao, Dequan, Liu, Hongyang, Ma, Ding, Chen, Jiawei, Jiao, Yueyue, Qin, Xuetao, Cai, Xiangbin, Wang, Maolin, Diao, Jiangyong, Wang, Linlin, Li, Chengyu, Ren, Pengju, Wen, Xiaodong, Wang, Ning, Rong, Junfeng, Xiao, Dequan, Liu, Hongyang, and Ma, Ding

Abstract

The hydrogenation of nitriles to amines, as an atom-economical synthetic route, has attracted wide attention in industrial production. Despite that some catalysts for nitrile hydrogenation have been investigated in recent years, achieving high activity and selectivity in this process remains a major challenge. Here, we fabricated an atomically dispersed Rh catalyst anchored on defect-rich nanodiamond-graphene (ND@G) via a deposition–precipitation strategy (Rh1/ND@G), which showed the highest activity (TOF = 2592 h–1) in the hydrogenation of benzonitrile reaction among all the known catalysts under mild reaction conditions (333 K, 0.6 MPa H2), and delivered high selectivity (>99%) toward secondary amines. Significantly, we prepared the Rh-cluster catalyst (Rhn/ND@G) and a series of atomically dispersed M1 catalysts (M = Rh, Ru, Pd, Ir, and Pt) to understand the size effect and metal-dependent effect in the hydrogenation of benzonitrile. Experimental and theoretical investigations revealed that the Rh1/ND@G catalyst has higher selectivity toward dibenzylamine than Rhn/ND@G, as it is less likely to form benzylamine on the Rh1 active sites. Meanwhile, the difference of adsorption energies (as a catalyst descriptor) between benzylideneimine and benzonitrile was used to understand the activity of benzonitrile hydrogenation influenced by the metal-dependent effect of M1 catalysts. Modulating the size and metal-dependent effects could lead to high catalytic performance, paving the way to design efficient nitrile hydrogenation catalysts.

Published
2023

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