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Combined multi-level quantum mechanics theories and molecular mechanics study of water-induced transition state of OH^- + CO_2 reaction in aqueous solution

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Chinese Physics B 2017年第10期26卷 200-204页

作者：李琛牛美兴刘鹏李永方王敦友 College of Physics and Electronics Shandong Normal University

The presence of a solvent interacting with a system brings about qualitative changes from the corresponding gas-phase reactions. A solvent can not only change the energetics along the reaction pathway, but also radically alter the reaction mechanism. Here, we investigated the water-induced transition state of the OH^-＋CO2→HCO3^- reaction using a multi-level quantum mechanics and molecular mechanics method with an explicit water model. The solvent energy contribution along the reaction pathway has a maximum value which induces the highest energy point on the potential of mean force. The charge transfer from OH^- to CO2 results in the breaking of the OH^- solvation shell and the forming of the CO2 solvation shell. The loss of hydrogen bonds in the OH^- solvation shell without being compensated by the formation of hydrogen bonds in the CO2 solvation shell induces the transition state in the aqueous solution. The calculated free energy reaction barrier at the CCSD（T）/MM level of theory, 11.8 kcal/mol, agrees very well with the experimental value, 12.1 kcal/mol.

关键词： transition state reaction pathway free energy barrier solvent effect

Effect of Interaction upon Translocation of Confined Polymer Chain Through Nanopore

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Chinese Journal of Chemical Physics 2010年第3期23卷 313-316,I0002页

作者：王瑶谢永军杨海洋张兴元中国科学技术大学高分子科学与工程系合肥230026

The effect of the interaction between nanopore and chain monomer on the translocation of a single polymer chain confined in a finite size square through an interacting nanopore to a large space has been studied by two-dimensional bond fluctuation model with Monte Carlo simulation. Results indicate that the free energy barrier before the successful translocation of the chain depends linearly on the chain length as well as the nanopore length for different pore-polymer interaction, and the attractive interaction reduces the free energy barrier, leading to the reduction of the average trapping time.

关键词： Monte Carlo simulation Polymer translocation Interaction free energy barrier

Integrated separation-electrochemical detection device based on wood column for online identification of enantiomer

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Nano Research 2024年第3期17卷 1893-1901页

作者： Junli Guo Yuanfei Xue Chenxi Zhao Junjian Zhao Zhida Gao Ye Mei Yan-Yan Song College of Sciences Northeastern UniversityShenyang 110004China State Key Laboratory of Precision Spectroscopy School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200062China NYU-ECNU Center for Computational Chemistry at NYU Shanghai Shanghai 200062China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

Chiral chemicals have attracted significant interest in the pharmaceutical industry,yet the separation methods to get pure enantiomers from racemic mixture are still *** date,the separation of enantiomers still mainly depends on chromatography using high-cost chiral stationary ***,wood channels were used as the handheld integrated device,and enantiomer separation was simultaneously detected using an electrochemical *** this method,a chiral UIO-66(L-UIO-66)modified enantiomer separation zone and carbonized wood based online detection zone are integrated along a single wood *** on the in situ separation results from the chronoamperometry data,the wood device shows excellent separation ability for a wide range of electrochemically active enantiomers,including 3,4-dihydroxyphenylalanine,amino acids,ascorbic acid,carnitine,and penicillamine with high chirality *** unbiased molecular dynamic simulations indicate that the excellent chiral recognition and separation are attributed to the different barriers from the bound states to the dissociated state of the enantiomers in the homochiral microenvironment of the *** integrated enantiomer separation-electrochemical detection device provides a novel,easy,and low-cost platform for the separation of pure enantiomer from racemic mixture.

关键词： wood column integrated separation-detection device enantioselectivity online sensing free energy barrier

A new association state of solutes in nanoconfined aqueous solutions

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Science China(Physics,Mechanics & Astronomy) 2016年第11期59卷 28-35页

作者： YuSong Tu Liang Zhao HaiPing Fang College of Physical Science and Technology Yangzhou University Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied Physics Chinese Academy of Sciences

Recently, we have found a reversible transition between the dispersion and aggregation states of solute molecules in aqueous solutions confined in nanoscale geometry, where solutes exhibit distinct behavior in a new association state from that in the dispersion and aggregation states observed usually in macroscopic systems. However, it remains unknown whether this new association state of solute molecules found in nanoconfined systems would vanish with the system size increasing and approaching the macroscopic scale. Here, we achieve the phase diagram of solute association states by making the analyses of Gibbs free energy of solutes in nanoconfined aqueous solutions in detail. In the phase diagram, we observe a closed regime with a finite system size of nanoconfined aqueous solutions and a solute concentration range, only in which there exists the new association state of solutes with the reversible transition between the aggregation and dispersion states, and there indeed exists an upper limit of the system size for the new association state, around several tens nanometers. These findings regarding the intimate connection between the system size and the solute association behavior provides the comprehensive understanding of the association dynamics of solutes in nanoconfined environment.

关键词： solute association states reversible transition nanoconfined aqueous solutions free energy barrier

Dissociation of liquid water on defective rutile TiO2 （110） surfaces using ab initio molecular dynamics simulations

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Frontiers of physics 2018年第3期13卷 53-59页

作者： Hui-Li Wang Zhen-Peng Hu Hui Li School of Physics Nankai University Tianjin 300071 China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Institute of Physics Chinese Academy of Sciences Beijing 100190 China

In order to obtain a comprehensive understanding of both thermodynamics and kinetics of water dissociation on TiO2, the reactions between liquid water and perfect and defective rutile TiO2 （110） surfaces were investigated using ab initio molecular dynamics simulations. The results showed that the free-energy barrier （-4.4 kcal/mol） is too high for a spontaneous dissociation of water on the perfect rutile （110） surface at a low temperature. The most stable oxygen vacancy （VOl） on the rutile （110） surface cannot promote the dissociation of water, while other unstable oxygen vacancies can significantly enhance the water dissociation rate. This is opposite to the general understanding that Vol defects are active sites for water dissociation. Furthermore, we reveal that water dissociation is an exothermic reaction, which demonstrates that the dissociated state of the adsorbed water is thermodynamically favorable for both perfect and defective futile （110） surfaces. The dissociation adsorption of water can also increase the hydrophilicity of TiO2.

关键词： ab initio molecular dynamics rutile (110) free energy barrier spontaneous reaction exothermic reaction

Interfacial coordination bonds accelerate charge separation for unprecedented hydrogen evolution over S-scheme heterojunction

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Chinese Journal of Catalysis 2024年第10期65卷 174-184页

作者： Chunxue Li Hao Lu Guixiang Ding Tianyi Ma Shiyong Liu Li Zhang Guangfu Liao College of Ecological Environment and Urban Construction Fujian University of TechnologyFuzhou 350118FujianChina School of Materials Science and Engineering Suzhou University of Science and TechnologySuzhou 215009JiangsuChina College of Materials Engineering Fujian Agriculture and Forestry UniversityFuzhou 350002FujianChina School of Science RMIT UniversityMelbourneVIC 3000Australia Jiangxi Province Key Laboratory of Functional Crystalline Materials Chemistry Jiangxi University of Science and TechnologyGanzhou 341000JiangxiChina State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile UniversityWuhan 430200HubeiChina

Inspired by natural photosynthesis,fabricating high-performance S-scheme heterojunction is regarded as a successful tactic to address energy and environmental ***,NH_(2)-MIL-125(Ti)/Zn_(0.5)Cd_(0.5)S/NiS(NMT/ZCS/NiS)S-scheme heterojunction with interfacial coordination bonds is successfully synthesized through in-situ solvothermal ***,the optimal NMT/ZCS/NiS S-scheme heterojunction exhibits comparable photocatalytic H_(2)evolution(PHE)rate of about 14876.7μmol h^(−1)g^(−1)with apparent quantum yield of 24.2%at 420 nm,which is significantly higher than that of recently reported MOFs-based *** interfacial coordination bonds(Zn–N,Cd–N,and Ni–N bonds)accelerate the separation and transfer of photogenerated charges,and the NiS as cocatalyst can provide more catalytically active sites,which synergistically improve the photocatalytic ***,theoretical calculation results display that the construction of NMT/ZCS/NiS S-scheme heterojunction also optimize the binding energy of active site-adsorbed hydrogen atoms to enable fast adsorption and *** Kelvin probe force microscopy,in-situ irradiation X-ray photoelectron spectroscopy,femtosecond transient absorption spectroscopy,and theoretical calculations provide sufficient evidence of the S-scheme charge migration *** work offers unique viewpoints for simultaneously accelerating the charge dynamics and optimizing the binding strength between the active sites and hydrogen adsorbates over S-scheme heterojunction.

关键词： Interfacial coordination bond S-schemeheterojunction Photocatalytic H_(2)evolution Charge dynamics free energy barrier

Designing high piezoelectric properties at the BaTiO_(3)–PbZrO_(3)–PbTiO_(3) phase boundary by Landau–Devonshire theory

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Journal of Advanced Dielectrics 2024年第2期14卷 33-41页

作者： Yu Song Xiaoming Shi Dan Li Jing Wang Houbing Huang School of Materials Science and Engineering Beijing Institute of Technology Beijing 100081P.R.China Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081P.R.China School of Electronic Information and Electrical Engineering Chengdu University Chengdu 610100P.R.China

Ferroelectric materials possessing exceptional piezoelectric attributes have garnered widespread utilization in various *** solution systems improve piezoelectric properties through multiphase mixing,but the methodologies for effective design remain *** on the Landau–Devonshire theory,we propose a theoretical design *** materials with morphotropic phase boundary(MPB)compositions are added with new elements to increase the free energy of the original stabilized phase and lower the energy barrier(EB).Flatter EBsand higher piezoelectric coefficients are found at the phase boundaries of the ternary *** calculating the phase diagram,piezoelectric coefficient,dielectric constant,polarization,and EBs,we reveal the origin of the highest piezoelectric coefficient at the phase *** study underscores the importance of the EBs for polarization rotation in characterizing piezoelectric properties and proposes a theoretical design method for exploring materials with high piezoelectric coefficients.

关键词： BaTiO_(3)-PbZrO_(3)-PbTiO_(3) piezoelectric properties free energy barrier thermodynamic calculation Landau-Devonshire theory

Theoretical Investigation on the Reaction Mechanism Morita-Baylis-Hillman Reactions: On the Predictability of First Principle Electronic Methods

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Theoretical Investigation on the Reaction Mechanism Morita-B...