Article
Energy & Fuels
Parisa Naeiji, Mengdi Pan, Manja Luzi-Helbing, Saman Alavi, Judith M. Schicks
Summary: A study was conducted to investigate the dissociation behavior of methane hydrates under different temperature and pressure conditions. Both experimental and simulated data showed that the behavior differed above and below the freezing point of water. At temperatures near or below freezing, CH4 hydrates exhibited self-preservation behaviors due to the formation of a quasi-liquid or amorphous phase at the outer layers of the hydrate crystal. Above the freezing point, dissociation appeared to initiate at the surface of the hydrate phase.
Article
Engineering, Mechanical
Ganlin Cheng, Bingzhe Chen, Fei Guo, Chong Xiang, Xiaohong Jia
Summary: Two polymers and five metal pairs were tested to determine their tribological properties under various low temperature and load conditions. Molecular dynamics simulation was employed to study the micro-tribological properties of friction pairs on the atomic scale. The macro-tribological performance test results were consistent with the simulation results, demonstrating similar trends. The study also revealed the evolution of the tribological mechanism and properties of the polymer interface under different low temperature working conditions on both macroscopic and atomic scales.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Chemical
Chong Qi, Yicheng Xing, Hong Yu, Yifu Bi, Pei Zhou, Han Wu, Rui Guo, Hangkai Zhang, Mingbo Wu, Wenting Wu
Summary: This paper investigates a method for converting methane into high-value chemicals using nonthermal plasma. By using Cu-decorated polymer carbon nitride as a catalyst, high selectivity of liquid products is achieved.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Chemistry, Physical
Pak Wing Chen, Debtanu Maiti, Ru-Fen Liu, Lars C. Grabow, Michael P. Harold
Summary: The performance of Pt + Pd/Al2O3 monolith catalysts under simulated exhaust gas conditions of natural gas vehicles (NGVs) was studied. The addition of Mn0.5Fe2.5O4 spinel enhanced the low temperature CH4 oxidation activity but limited high temperature CH4 conversion. The negative impact of spinel on steam reforming of CH4 (SRM) was attributed to the migration of base metal species and blockage of PGM active sites. A zoned catalyst design was developed to mitigate detrimental metals migration and enhance methane conversion.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Zhengchong Zhao, Haiyang Yang, Jingjing He, Fuqiang Hu, Fan Cheng, Hai Liu, Chunli Gong, Sheng Wen
Summary: Asphaltene extracted from heavy oil was oxidized with a mixture of propionic anhydride and hydrogen peroxide at a low temperature. The oxidation process involved oxygen addition, side chain cleavage, and condensation reactions. The oxidation products were divided into soluble and insoluble fractions, with the soluble fraction containing mainly fatty acids and esters. The degree of aromatic ring condensation in the insoluble fraction was slightly higher than the pristine asphaltene. This low-temperature oxidation technology can improve the profitability of heavy oil processing.
Article
Engineering, Environmental
Jingyue Sun, Cong Chen, Wenfeng Hu, Jingwei Cui, Lanlan Jiang, Yu Liu, Yuechao Zhao, Weizhong Li, Yongchen Song
Summary: The CO2 sequestration and enhanced gas recovery (CS-EGR) technology is effective in alleviating the greenhouse effect and energy crisis, especially in understanding the competitive adsorption behavior of CO2 and CH4 in shale matrix. The graphene-MMT heterogeneous surface pore model plays a vital role in studying the competitive adsorption features.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Energy & Fuels
Bernadette R. Cladek, S. Michelle Everett, Marshall T. McDonnell, Dayton G. Kizzire, Matthew G. Tucker, David J. Keffer, Claudia J. Rawn
Summary: The presence of CO2 in mixed hydrates increases the stability range and creates a barrier for CH4 to completely leave the structure. When CH4 and CO2 co-occupy the hydrate, the host structure is more strongly distorted than in pure CH4 and CO2 hydrates, but this effect diminishes with increasing temperature.
Article
Energy & Fuels
Ping Wang, Xiaofang Li, Zhengwu Tao, Sen Wang, Jiawei Fan, Qihong Feng, Qingzhong Xue
Summary: The study investigates the miscible behaviors of different gas and crude oils in nanoslits through molecular dynamics simulations, finding that gas type, polarity, and crude oil chain length can affect the miscibility process, with CO2, CH4, C3H8, and N2 being more miscible with apolar crude oil.
Article
Chemistry, Physical
Zhenlei Wang, Fang Yan, Lu Bai, Xiangping Zhang, Xiaomin Liu, Xiaochun Zhang
Summary: Ionic liquid/polymer hybrid membranes are a research hotspot for CO2 separation, but the lack of molecular insight into the separation mechanism hinders their development. This study investigates the CO2/CH4 separation process in PVDF membranes with [Bmim][PF6] and [Bmim][NTf2] through molecular dynamics simulations. The results show that ILs can enhance the flexibility of PVDF chains and improve gas permeation and diffusion, with [Bmim][NTf2]/PVDF membrane exhibiting better CO2/CH4 separation performance.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Engineering, Chemical
Fang Yan, Yandong Guo, Zhenlei Wang, Linlin Zhao, Xiaochun Zhang
Summary: Ionic liquids (ILs)/graphene oxide (GO) membranes are a promising alternative for CO2 separation. This study investigates the correlation between the microstructure of ILs/GO and CO2 separation performance using molecular dynamics simulation. The results show that a dense cation adsorption layer forms near GO, facilitating CO2 adsorption. CO2/CH4 mainly distributes around the ILs area of the membrane, improving gas selectivity. Decreasing the layer spacing increases solubility selectivity but may decrease diffusion selectivity. Low viscosity ILs enhance diffusion selectivity. [Bmim][TF2N]/GO membrane is predicted to have superior CO2/CH4 separation performance.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Article
Polymer Science
Dongqing Shao, Qun Zhang, Peng Xu, Zhouting Jiang
Summary: The effect of temperature and salt solution on the structural characteristics of protein 1BBL was studied using molecular dynamics simulations. Non-bonded energy and structural stability of the protein in salt solutions with varying concentrations and temperatures were investigated. The study demonstrated that the electrostatic potential energy and van der Waals energy of the system changed in opposite directions under the influence of the external environment, with the former exhibiting more significant changes. Structural parameters, such as root mean square deviation and radius of gyration, initially increased and then decreased with increasing salt concentration. The protein exhibited a loose and less stable structure when immersed in a monovalent solution with a salt concentration of 0.8 mol/L. Furthermore, the salt concentration corresponding to the highest structural parameters in the monovalent solution was twice that in the divalent solution. It was concluded that the protein had a compact and stable structure when immersed in salt solutions with a high concentration of 2.3 mol/L. Analysis of root mean square deviation and root mean square fluctuation also revealed that structural stability and chain flexibility were strongly influenced by temperature. These findings contribute to a better understanding of the structural characteristics of proteins in salt solutions with varying concentrations and temperatures.
Article
Chemistry, Multidisciplinary
Subin Lee, Jong Hwan Park, Chan Gyu Park, Dae-Yong Jeong, Nong Moon Hwang
Summary: The study investigated the role of charged secondary nanoparticles in the aerosol deposition process, revealing that the positive charge enhanced plastic deformation for the evolution of dense films. This was supported by capturing and observing the secondary nanoparticles with transmission electron microscopy, showing their influence on the film formation during aerosol deposition.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Biochemistry & Molecular Biology
Shir Nee Ong, Nor Hafizah Ahmad Kamarudin, Fairolniza Mohd Shariff, Noor Dina Muhd Noor, Mohd Shukuri Mohamad Ali, Raja Noor Zaliha Raja Abd. Rahman
Summary: The effects of methanol and ethanol on the stability and activity of lipase were examined in this study. High concentrations of alcohols and elevated temperatures were found to induce the opening of the lid of the lipase, which could enhance its catalytic activity. However, the stability of the lipase was compromised in organic media containing alcohols.
JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS
(2023)
Article
Engineering, Chemical
Subhadeep Dasgupta, M. Rajasekaran, Projesh K. Roy, Foram M. Thakkar, Amar Deep Pathak, K. Ganapathy Ayappa, Prabal K. Maiti
Summary: Carbon molecular sieving membranes (CMSM) derived from 6FDA/BPDA-DAM polymer precursors show excellent adsorption and selectivity towards CO2. The length of individual carbon chains determines the morphologies and porosity of the membranes. Using molecular dynamics (MD) simulations, the study provides insights into the most feasible structures formed in experiments and estimates the corresponding membrane density. Grand canonical Monte Carlo simulations reveal enhanced adsorption capacity and selectivity for CO2 in binary mixtures of gases. The work demonstrates how slight modifications in the physical arrangements of chemical components can significantly impact the porosity and gas adsorption capacities of molecular sieving membranes.
JOURNAL OF MEMBRANE SCIENCE
(2022)
Article
Chemistry, Physical
Xiang Chen, Donger Chen, Li-Hua Gan
Summary: The study investigates the partial oxidation of methane to produce C2H2 using the reactive force field molecular dynamics method. It reveals that the process involves oxidation reactions, cracking and reforming reactions, with C2H3 and C2HnO as main precursors, and the yield of C2H2 depends on the species produced during heating. Optimal process parameters are determined for reference in process optimization.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Simone L. Waite, Amir Karton, Bun Chan, Alister J. Page
Summary: The study demonstrates that the DFTB3-D/3ob method accurately predicts the heats of formation for fullerenes and reproduces subtle trends in structural isomers, providing valuable insights for predicting thermochemical stabilities of giant fullerenes and similar nanocarbon architectures.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Li Ping Ding, Ben McLean, Ziwei Xu, Xiao Kong, Daniel Hedman, Lu Qiu, Alister J. Page, Feng Ding
Summary: This study reveals a key aspect of the carbon nanotube-catalyst interface, namely, that the interfacial energy of the carbon nanotube-catalyst edge is contact angle-dependent. By reducing the contact angle, the interfacial formation energy is decreased, thus driving the growth of carbon nanotubes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
Krishna K. Ghose, Alicia Bayon, Alister J. Page
Summary: The structural and thermochemical properties of hexagonal and cubic BaMnO3 perovskites were predicted using first principles calculations. The study demonstrated the atomic contributions to the thermochemical properties through the phonon dispersions and vibrational density of states.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Biochemistry & Molecular Biology
Enis Nadia Md Yusof, Mohammad Azam, Siti Syaida Sirat, Thahira B. S. A. Ravoof, Alister J. Page, Abhi Veerakumarasivam, Thiruventhan Karunakaran, Mohd Rizal Razali
Summary: A novel series of transition metal complexes were synthesized using S-4-methylbenzyl-beta-N-(2-methoxybenzylmethylene)dithiocarbazate ligand. The compounds were characterized and evaluated for their cytotoxic behavior. Complex 2 showed promising results against cancer cell lines MCF-7 and MDA-MB-213.
BIOINORGANIC CHEMISTRY AND APPLICATIONS
(2022)
Article
Multidisciplinary Sciences
Kasimir P. Gregory, Gareth R. Elliott, Erica J. Wanless, Grant B. Webber, Alister J. Page
Summary: The importance of ion-solvent interactions in predicting specific ion effects cannot be underestimated. However, investigations in nonaqueous systems are limited due to data deficiency. We report a database containing over 3000 simulations to study ion behavior in aqueous and non-aqueous solvent environments.
Article
Chemistry, Physical
Anand Kumar, Vincent S. J. Craig, Alister J. Page, Grant B. Webber, Erica J. Wanless, Gunther Andersson
Summary: The distribution of ions at the glycerol-vapor interface is found to be non-monotonic, with anions concentrated at the outermost region and cations depleted. The specific ion effects depend on the counterions, with Cs', K', and Na' ions leading to a desorption of Br- ions from the interface. This study provides insights into the mechanisms of specific ion effects in this system and at interfaces.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Physical
Izaac Mitchell, Lu Qiu, Alister Page, Lowell D. Lamb, Feng Ding
Summary: This study provides insights into the formation mechanisms and temperature window of fullerene formation, facilitating better optimization of experimental methods.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Review
Energy & Fuels
Krishna K. Ghose, Joshua J. Brown, Terry J. Frankcombe, Alister Page, Alicia Bayon
Summary: Water splitting driven by solar energy is a promising strategy for producing renewable hydrogen with minimal environmental impact. Perovskite oxides have unique structural features that make them suitable for water splitting applications. Density functional theory (DFT) calculations are used to accurately predict the critical properties of perovskite oxides relevant to water splitting processes. The challenges associated with the choice of exchange-correlation functional in DFT methods are discussed in this review.
WILEY INTERDISCIPLINARY REVIEWS-ENERGY AND ENVIRONMENT
(2023)
Article
Chemistry, Physical
Kasimir P. Gregory, Grant B. Webber, Erica J. Wanless, Alister J. Page
Summary: Hofmeister effects and specific ion effects are common in biological systems, but they may not always follow the Hofmeister series in complex biological systems like ion channels. Studying the interaction energies between anions and amino acids can help explain why certain binding interactions are favored. The strength of interactions follows the Hofmeister series and increases with the polarity of amino acids, except for negatively charged amino acid side chains. Interactions involving both the side chain and protic moieties of the backbone are generally most favorable, and the total interaction energy is primarily determined by the electrostatic component and the thorn ('sho') value of the anion.
ELECTRONIC STRUCTURE
(2023)
Article
Chemistry, Physical
Thomas Bourke, Kasimir P. Gregory, Alister J. Page
Summary: The origins and behaviour of specific ion effects have been extensively studied in water and nonaqueous molecular solvents. However, the impacts of specific ion effects on more complex solvents, such as nanostructured ionic liquids, are still unclear. This study hypothesizes that the influence of dissolved ions on the hydrogen bonding in nanostructured ionic liquid PAN constitutes a specific ion effect.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Chemistry, Physical
Sophie Baker, Joshua Pagotto, Timothy T. Duignan, Alister J. Page
Summary: Neural network potentials have proven to be an efficient tool for accelerating ab initio molecular dynamics simulations. This study explores the use of existing DFTB molecular dynamics data to train graph neural network potentials and accurately reproduce solvation structures in NaCl solutions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Anand Kumar, Vincent S. J. Craig, Hayden Robertson, Alister J. Page, Grant B. Webber, Erica J. Wanless, Valerie D. Mitchell, Gunther G. Andersson
Summary: Using neutral impact collision ion scattering spectroscopy (NICISS), the concentration depth profiles (CDPs) of various monovalent ions at the vapor-formamide interface were directly measured. The results reveal a reverse Hofmeister series in the presence of inorganic ions at the vapor-formamide interface compared to the water-vapor interface, with the CDPs being independent of the counterion for most ions studied.
Article
Chemistry, Multidisciplinary
Xinyu Li, Javen Qinfeng Shi, Alister J. Page
Summary: Despite the current challenges in commercial-scale graphene production using chemical vapor deposition (CVD), this study introduces a new approach combining high-throughput density functional theory and machine learning to identify new prospective catalyst materials with comparable performance to established catalysts. The approach discovered combinations of early- and late-transition metals, including unconventional partners like Zr, Hf, and Nb. This study highlights the importance of finding novel catalyst materials for CVD growth of low-dimensional nanomaterials.
Article
Chemistry, Physical
Xinyu Li, Raymond Chiong, Zhongyi Hu, Alister J. Page
Summary: This study demonstrates the use of local environment pooling instead of global pooling in conjunction with graph neural networks to predict adsorption energy. We achieved mean absolute errors of 0.096 and 0.073 eV in predicting CO and H adsorption energies, respectively, on transition metal catalyst surfaces, surpassing the performance of previously reported state-of-the-art machine learning models.
COMPUTATIONAL AND THEORETICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Kasimir P. Gregory, Gareth R. Elliott, Hayden Robertson, Anand Kumar, Erica J. Wanless, Grant B. Webber, Vincent S. J. Craig, Gunther G. Andersson, Alister J. Page
Summary: Specific ion effects (SIE) have been studied for over 130 years and are observed in various fields. However, there is currently no general theory to explain ion specificity. This review explores the historical explanations for SIE in water, the properties of key ions, and the behavior of ions at the liquid-vapor interface. It also discusses SIE in mixed electrolytes, nonaqueous solvents, and highly concentrated electrolyte solutions, which are exciting frontiers with relevance to biological and electrochemical applications. The article concludes by summarizing the challenges and opportunities in SIE research and the potential for a general predictive theory.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)