Article
Materials Science, Paper & Wood
Antti Paajanen, Aleksi Rinta-Paavola, Jukka Vaari
Summary: This study investigates the thermal decomposition of cellulose using molecular simulations, revealing that depolymerization via glycosidic bond cleavage initiates the degradation process, leading to the formation of various oxygenates with water mainly formed in later stages. The reaction rate of glycosidic bond cleavage follows a sigmoidal model, providing insights into the mechanism of cellulose fast pyrolysis. The simulations, however, lack anhydrosugar forming reactions and thus offer limited understanding for industrial conditions.
Article
Chemistry, Multidisciplinary
Giorgio Conter, Kailu Xiao, Xianqian Wu, William A. Goddard III, Alessandro Fortunelli
Summary: In this study, the mechanical response of super-low density amorphous carbonaceous materials was investigated computationally. It was found that these materials exhibit extremely low shear yield stress, and the analysis of atomistic relaxation mechanisms revealed a collective and cooperative plastic relaxation mode in the form of shear bands within the clumps. These findings provide insights into the plastic deformation modes of carbon aerogels and lay the foundation for developing a predictive multi-scale modeling of their mechanical properties.
Article
Multidisciplinary Sciences
Yiwen Xiao, Lang Chen, Kun Yang, Deshen Geng, Jianying Lu, Junying Wu
Summary: The study shows that guest molecules significantly increase the energy level of the host-guest explosive system, accelerate the thermal decomposition reactions of the explosives, and play a more important role in the intermediate exothermic reaction stage.
SCIENTIFIC REPORTS
(2021)
Article
Energy & Fuels
Aditya Lele, Hyunguk Kwon, Karthik Ganeshan, Yuan Xuan, Adri C. T. van Duin
Summary: This study investigates the initial fuel pyrolysis of four bicyclic compounds using ReaxFF force field based molecular dynamics simulations. The bicyclic fuels have faster or comparable decomposition rates compared to existing jet-fuels. The decomposition pathways involve central bond cleavage and ring opening, with significant temperature dependence.
Article
Chemistry, Multidisciplinary
Luca Brugnoli, Katsuaki Miyatani, Masatoshi Akaji, Shingo Urata, Alfonso Pedone
Summary: Reactive molecular dynamics simulations were used to investigate the chemical mechanical polishing (CMP) process of silica glass surfaces with ceria (111) and (100) surfaces commonly found in ceria nanoparticles. Different glass surface models were created to study their morphology and chemistry after interaction with acidic, neutral, and basic water solutions and ceria surfaces. It was found that the degree of hydroxylation of the silica slab affected its reactivity, and the (111) ceria surface showed higher reactivity at neutral pH. The atomic-scale mechanisms of silica removal at the two ceria surfaces were described.
Article
Chemistry, Physical
Yang Zhou, Shuai Xiao, Luqing Cheng, Yuan Chen, Jinhui Tang, Wei She
Summary: This study used molecular dynamics simulations to investigate the effects and mechanisms of different molecular chain lengths of polyacrylic acid (PAA) on toughening calcium silicate hydrate (CSH) in cement-based materials. The results showed that an optimal molecular chain length of polymers contributes to the largest toughening effect on the matrix, leading to a significant increase in fracture energy. The configuration evolution of the PAA molecule during tensile tests determines the toughening effect, as the polymer unfolds and matches the defects of CSH, resulting in a more homogeneous stress distribution and increased toughness. Furthermore, a theory of strain rate/optimal chain length is proposed based on the simulation results, which suggests that the optimal toughening effect can be achieved when the molecular chain length of the organic component is 1.3-1.5 times the largest defect size of the inorganic matrix.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Yang Zhou, Shuai Xiao, Luqing Cheng, Yuan Chen, Jinhui Tang, Wei She
Summary: This study used molecular dynamics simulations to investigate the effects and mechanisms of different molecular chain lengths of polyacrylic acid (PAA) on toughening calcium silicate hydrate (CSH). The simulation results showed that an optimal molecular chain length of polymers significantly enhances the toughness of the matrix, resulting in up to a 60.98% increase in fracture energy. The configuration evolution of the PAA molecule during uniaxial tensile tests influenced the toughening effect, and a more homogeneous stress distribution favored an increase in toughness. Additionally, a theory of strain rate/optimal chain length was proposed, suggesting that the optimal toughening effect can be achieved when the organic component's molecular chain length is 1.3-1.5 times the largest defect size of the inorganic matrix. This study provides molecular-scale insights into the toughening mechanisms of an organic/inorganic system and has practical implications for improving the toughness of cement-based materials.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Fanqin Xiong, Ruixuan Xu, Hongqi Nie, Qilong Yan, Yuxin Wu, Jun Liu, Jiuyu Chen, Yunlan Sun
Summary: The mechanism of thermal decomposition of RDX catalyzed by nano-sized aluminum powder was investigated using reactive molecular dynamics simulations and density functional theory calculations. The results showed that an optimal concentration of aluminum significantly facilitates the thermal disintegration of RDX, with the dissociation of nitro group as the main reaction pathway.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Heng Liu, Qingmin Li, Jingrui Wang, Yuheng Jiang, A. Manu Haddad
Summary: This study proposed a gas mixing scheme screening method based on molecular dynamics simulation to suppress the generation of solid decomposition products of HFO1234ze(E). Experimental results showed that an appropriate amount of O-2 can effectively inhibit the formation of solid products.
Article
Electrochemistry
Yu Wu, Qintao Sun, Yue Liu, Peiping Yu, Bingyun Ma, Hao Yang, Miao Xie, Tao Cheng
Summary: Metallic lithium is a promising material for rechargeable lithium-based batteries, but its application is hindered by the growth of lithium dendrites and the formation of dead lithium. A recent electrolyte, with low concentration and containing a single salt and two solvents, has attracted attention due to its ability to achieve high energy efficiency. However, the underlying reaction mechanism and structure of the solid electrolyte interface (SEI) are still unclear, which poses challenges for further improvement. By using a hybrid ab initio and reactive force field (HAIR) method, the authors of this study revealed the reaction mechanisms and formation pathway of the SEI. Their findings provide valuable insights for the design of advanced electrolytes.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Xiaoya Chang, Qingzhao Chu, Dongping Chen
Summary: The anisotropic combustion of aluminum nanoparticles under flow impact is examined using reactive molecular dynamics simulations in a wide pressure range, revealing three combustion modes and two critical thresholds of energy transfer rate, with a proposed model competent in predicting combustion modes and describing energy transfer on particle surfaces.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Liqiang Ai, Haishen Huang, Yusi Zhou, Min Chen, Yongjun Lu
Summary: A new ReaxFF force field was developed to study the interactions between Fe/Ni binary alloy surface and supercritical water, revealing a selective oxidation of Fe by SCW leading to dealloying of the alloy surface. The study sheds light on the oxidation mechanism of Fe/Ni alloy surfaces in SCW and indicates the potential for improving oxidation resistance through adjustments in the content and distribution of nickel atoms in the alloy.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Qingzhao Chu, Xiaoya Chang, Kang Ma, Xiaolong Fu, Dongping Chen
Summary: A neural network potential (NNP) is used to investigate the complex reaction dynamics of 1,3,5-trinitro-1,3,5-triazine (RDX) thermal decomposition. The NNP accurately describes the physical and chemical properties of RDX crystals, and reveals the reaction mechanism of RDX decomposition.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Namsoon Eom, Maria E. Messing, Jonas Johansson, Knut Deppert
Summary: Metal oxide shell layers can improve the performance of metal nanoparticles in various applications. Computational modeling, particularly on the sintering mechanism of metal@ metal oxide nanoparticles, is scarce. The coalescence process of metal nanoparticles with amorphous oxide shell is mainly facilitated by surface atoms and grain-boundary-like diffusion. Surface diffusion is highly localized, contrary to common understanding of freely moving high-mobility surface atoms.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Chaeyeong Kim, Takuji Oda
Summary: In this study, a machine learning moment tensor potential that accurately simulates the interface systems between liquid Na and solid Na2O was developed. The potential was trained using supervised and active learning to ensure DFT-level accuracy, and an empirical correction was applied to achieve experimental accuracy. As a result, the basic properties of liquid Na and solid Na2O were accurately simulated.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Yujie Liu, Marita Coza, Victor Drozhzhin, Yannis van den Bosch, Lingqian Meng, Rim van de Poll, Emiel J. M. Hensen, Nikolay Kosinov
Summary: This study compares the catalytic performance and stability of Re, Mo, and Fe-based zeolite catalysts in the methane dehydroaromatization reaction. The results show that Re/ZSM-5 has the highest catalytic activity, while Fe/ZSM-5 has the best stability. The active metal species in each catalyst were determined to be Re-0 and Fe2+. It was also found that the slow growth of hydrocarbon pool intermediates inside the pores of Fe/ZSM-5 explains its poor catalytic performance.
Article
Chemistry, Physical
Francesco Cannizzaro, Emiel J. M. Hensen, Ivo A. W. Filot
Summary: This study investigates the promoting role of Ni in In2O3-catalyzed CO2 hydrogenation using density functional theory and microkinetic modeling. It is found that a supported cluster of eight Ni atoms leads to high methanol selectivity, while single Ni atoms either doped in or adsorbed on the In2O3 surface mainly catalyze CO formation. This research provides important theoretical insights for the design and improvement of CO2 hydrogenation catalysts.
Article
Engineering, Chemical
Panos D. Kouris, Alberto Brini, Eline Schepers, Michael D. Boot, Edwin R. Van den Heuvel, Emiel J. M. Hensen
Summary: Lignin can be converted into a lignin oil containing phenolic monomers through a catalytic depolymerization process using supercritical ethanol and a mixed metal oxide catalyst. This study evaluated the viability of this lignin conversion technology and determined the qualitative and quantitative relationships between the process parameters and the product streams. The response surface methodology analysis showed that the selected input factors and their interactions are significant for determining the product yields.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Physical
Luke M. van Koppen, A. Iulian Dugulan, G. Leendert Bezemer, Emiel J. M. Hensen
Summary: This study reports various deactivation pathways of cobalt nanoparticles supported on P25 titania under simulated high conversion conditions using in situ Mossbauer spectroscopy. It was found that a fraction of metallic cobalt was oxidized under humid Fischer-Tropsch synthesis (FTS) conditions, and the amount of oxidized cobalt was independent of the cobalt loading. The formation of cobalt-titanate-like compounds was observed only under very high water-to-hydrogen ratios in the absence of carbon monoxide. Steam significantly enhanced cobalt sintering under FTS conditions, suggesting that deactivation under humid FTS conditions is not only caused by cobalt oxidation but also by enhancing sintering of the active phase.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Yujie Liu, Aleksei Bolshakov, Marita Coza, Victor Drozhzhin, Emiel J. M. Hensen, Nikolay Kosinov
Summary: Dehydroaromatization of methane (MDA) under non-oxidative conditions is a promising reaction for direct valorization of natural gas and biogas. Fe-modified ZSM-5 catalysts prepared by direct hydrothermal synthesis, containing isomorphously substituted Fe-sites, exhibit superior MDA activity compared to impregnated Fe/ZSM-5 catalysts. The higher activity of [Fe,Al]ZSM-5 can be attributed to the transformation of tetrahedral Fe3+ into octahedral Fe2+ active sites during the MDA reaction.
Article
Chemistry, Multidisciplinary
Luc C. J. Smulders, Johan H. van de Minkelis, Johannes D. Meeldijk, Min Tang, Anna Liutkova, Kang Cheng, S. Tegan Roberts, Glenn J. Sunley, Emiel J. M. Hensen, Petra E. de Jongh, Krijn P. de Jong
Summary: In this study, the heat treatment of the catalyst precursor was found to influence the location of Pd precursor within SAPO-11 and ZSM-22 zeotype materials, which in turn affects the performance of the catalyst. The catalytic performance of the Pd-on-zeotype catalysts prepared using the direct reduction approach is intermediate between that of the Pd-in-zeotype catalysts prepared using the calcination-reduction approach and that of the Pd-on-alumina catalysts.
CHEMISTRY-SWITZERLAND
(2023)
Article
Chemistry, Physical
Ferdy J. A. G. Coumans, Brahim Mezari, Emiel J. M. Hensen
Summary: The role of Lewis and Bronsted acid sites in the Diels-Alder cycloaddition reaction for synthesizing p-xylene has been investigated. Catalysts containing Al3+ and Ga3+ demonstrated higher yields, while catalysts without Bronsted acid sites exhibited lower yields.
Article
Chemistry, Physical
Beata Kizior, Aneta Jezierska, Bartlomiej M. Szyja
Summary: The theoretical investigation of partial oxidation of methane to methanol using Ru-porphyrin complexes as catalysts revealed the significant role of the Spin Crossover phenomenon in the reaction kinetics, and the impact of non-covalent interactions on the electronic structure during the reaction.
Article
Chemistry, Inorganic & Nuclear
Francesco Mattarozzi, Marisol Tapia Rosales, Rim C. J. van de Poll, Emiel J. M. Hensen, Peter Ngene, Petra E. de Jongh
Summary: The electrochemical reduction of CO2 to produce sustainable fuels and chemicals has gained significant attention, with surface-modified carbons being found to catalyze the CO2RR. This study introduces a strategy for surface modification of commercially available carbon materials by incorporating oxygen and nitrogen surface groups while maintaining their graphitic structure. The results highlight the significant impact of surface group chemistry and point of zero charge (PZC) on CO2RR activity, selectivity, and turnover frequency. Nitrogen-containing surface groups demonstrate high selectivity for CO formation in comparison to oxygen-containing surface groups and carbon without surface groups, indicating the tunability of carbon's selectivity towards CO2RR through surface functionalization.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Energy & Fuels
Mohammad Fereidooni, Victor Marqurez, C. V. Paz, Emiel J. M. Hensen, Valery Muravev, Pantita Trongjitraksa, Martin Salazar Villanueva, Supareak Praserthdam, Piyasan Praserthdam
Summary: Artificial photosynthesis is a promising method for reducing atmospheric CO2 concentration by converting CO2 and H2O into valuable compounds. This study explores the photocatalytic activity of ultrathin indium tin oxide (ITO) films on different substrates for CO2 reduction. The reaction mechanism and viable pathways for CO2 conversion to CO and CH4 are proposed based on theoretical models and simulations. The findings emphasize the significance of catalyst design and reaction media configuration for high activity and stability.
Article
Chemistry, Physical
Lulu Chen, Ivo A. W. Filot, Emiel J. M. Hensen
Summary: In this study, the reverse water-gas shift (rWGS) reaction on Ru/CeO2 SAC was investigated using density functional theory and microkinetic modeling. The results showed that Ru(OH)(3)-(OH) is the dominant active site at low temperatures, while a Mars-van Krevelen mechanism is preferred at elevated temperatures due to the facile formation of oxygen vacancies.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Michel P. C. Van Etten, Michelle E. De Laat, Emiel J. M. Hensen, Ivo A. W. Filot
Summary: Structure sensitivity is crucial in heterogeneous catalysis, and the Fischer-Tropsch reaction serves as a prominent example of such reactivity. The size of nanoparticles plays a significant role in determining the activity and selectivity of this reaction, which holds true for various support materials. A ReaxFF force field is developed to understand why the interaction between metal and support does not affect this trend. The study finds that step-edge sites with an FCC(110) motif remain insensitive to the type of support, and they are primarily responsible for the observed atom-based Fischer-Tropsch synthesis activity, thus rationalizing the structure sensitivity.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Elzbieta Dziadyk-Stopyra, Ionut Tranca, Daniel Smykowski, Bartlomiej M. Szyja
Summary: We present a DFT analysis comparing the role of Cu-Ni synergistic effect with pure Cu catalyst in CO2 reduction to C2H4. The study focuses on the thermodynamic stability of reactive intermediates along the proposed pathway. Results show that addition of Ni decreases the potential needed for the reaction and leads to different preferred pathways based on Cu:Ni ratio and stability of intermediates. This suggests that the presence of Ni can change the reaction mechanism despite Cu's direct interaction with the intermediates.
Article
Energy & Fuels
Douglas Romero, Marcello Rigutto, Emiel J. M. Hensen
Summary: The mechanism of n-hexadecane (n-C16) hydroisomerization/hydrocracking was investigated using bifunctional catalysts with Pd and Pt as (de)hydrogenation components and large-pore zeolites and (ordered) mesoporous materials as acidic supports. The results showed that the isomer distribution and cracked products distribution changed with the increase of n-C16 conversion.
Article
Chemistry, Physical
Ferdy J. A. G. Coumans, Aleksei Bolshakov, Rim C. J. van de Poll, Dimitra Anastasiadou, Brahim Mezari, Emiel J. M. Hensen
Summary: A variety of methods were used to synthesize amorphous silica-alumina (ASA) and investigate the role of aluminum species and surface area in catalytic reactions. The study found that Bronsted acidity is crucial for p-xylene formation.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
