Article
Chemistry, Physical
Ya Bai, Jinjia Liu, Tao Wang, Yu-Fei Song, Yong Yang, Yong-Wang Li, Xiaodong Wen
Summary: In this study, a unified calculation method was used to explore the adsorption, dissociation, and reduction behaviors of hydrogen on Fe5C2 surfaces. The results showed that the dissociation of hydrogen molecule is thermodynamically and kinetically favorable, and it strongly affects the adsorption energy. Furthermore, the equilibrium crystalline morphology evolution of Fe5C2 was constructed using Wulff theorem, and the reduction process of carbon vacancies was investigated.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Seunghee Cha, Heewon Kim, Hyunkyung Choi, Chul Sung Kim, Kyoung-Su Ha
Summary: Chi-Fe5C2, a highly active phase in Fischer-Tropsch synthesis, was successfully synthesized using a wet-chemical route without the need for pre-activation. The encapsulation of chi-Fe5C2 nanoparticles with mesoporous silica was found to effectively protect them from deactivation and re-oxidation, while maintaining their phase intact. The CO2 selectivity of stabilized chi-Fe5C2 was very low, indicating its potential as a catalyst for Fischer-Tropsch synthesis.
Article
Chemistry, Physical
Huabo Zhao, Hong Jiang, Meng Cheng, Quan Lin, Yijun Lv, Yao Xu, Junzhong Xie, Jin-xun Liu, Zhuowu Men, Ding Ma
Summary: Boron adsorption on the chi-Fe5C2 catalyst can improve its stability and activity, suppress coking, and expose more active planes to facilitate CO activation. Co-adsorbed boron atoms have little impact on the barrier of CO direct dissociation in most cases, but can activate CO on boron with carbon termination in specific situations.
APPLIED CATALYSIS A-GENERAL
(2021)
Article
Chemistry, Physical
Lei Tang, Lei He, Yang Wang, Bingxu Chen, Wei Xu, Xuezhi Duan, An-Hui Lu
Summary: Selective synthesis of chi-Fe5C2 catalysts was achieved by interfering surface reactions during thermal treatment, resulting in high CO conversion and selectivity under the atmosphere of 64 %H-2/32 %CO/4 %Ar.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Materials Science, Ceramics
Huaxin Li, Takaaki Koyanagi, Caen Ang, Yutai Katoh
Summary: The study successfully demonstrated the joining of SiC materials at relatively low temperature through the electric current-assisted joining (ECAJ) method. Enhancing the current passage achieved the joining of low-resistivity grade, nitrogen doped beta-SiC; rapid crystal growth of textured SiC was found at the interface when joining at higher temperatures.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Multidisciplinary Sciences
Di Wang, Chenkun Zhou, Alexander S. Filatov, Wooje Cho, Francisco Lagunas, Mingzhan Wang, Suriyanarayanan Vaikuntanathan, Chong Liu, Robert F. Klie, Dmitri V. Talapin
Summary: Two-dimensional transition-metal carbides and nitrides (MXenes) are extensively studied materials with diverse applications in energy storage. We demonstrate a direct synthesis route for scalable and atom-economic production of MXenes, including previously unattainable compounds, by reactions of metals and metal halides with graphite, methane, or nitrogen. The directly synthesized MXenes exhibit excellent energy storage capacity for lithium-ion intercalation, and their growth can be controlled to form unique morphologies such as carpets and spherulites.
Article
Chemistry, Physical
Vorranutch Itthibenchapong, Pongkarn Chakthranont, Chanchai Sattayanon, Teera Butburee, Kajornsak Faungnawakij, Supawadee Namuangruk
Summary: The research investigated the effect of Pt, Ni, and Cu promoters on MoO3-x/TiO2 catalysts in the hydrodeoxygenation (HDO) reaction of p-cresol through experiments and density functional theory (DFT) calculations. The study found that the different promoters had an impact on the catalyst's activity, with PtMoO3-x/TiO2 showing the best performance.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Lei Tang, Xin Huang, Jingyu Ran, Fan Guo, Juntian Niu, Huayu Qiu, Zhiliang Ou, Yunfei Yan, Zhongqing Yang, Changlei Qin
Summary: In this study, the performances of direct and oxygen-assisted activation of C-H bond for dry reforming of methane (DRM) reaction were investigated using Ni(111), Rh/Ni(111), and Rh-6/Ni(111) catalysts. The results showed that doping Rh onto Ni weakened the adsorption strength of the intermediate and enhanced the activation of the C-H bond. The energy barriers for direct dissociation of CH3* -> CH2* + H* and CH2* -> CH* + H* were much lower compared to oxygen-assisted dissociation of CH3* + O* -> CH3O* and CH2* + O* -> CH2O* for all three catalysts. The optimal reaction path for DRM was CH4* -> CH3* -> CH2* -> CH*. Furthermore, the dissociation of CH * favored the oxygen-assisted pathway of CH & lowast; + O & lowast; -> CHO & lowast;, preventing carbon deposition.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Ning Liu, Jianjun Mao, Xilin Zhang, Yan Wang, Zongxian Yang, Wenchang Lu
Summary: In this study, a Pd monolayer on ZrC(001) surface was proposed as an effective catalyst for the dissociation of oxygen. The coverage of Pd was found to significantly impact the adsorption and dissociation of O-2. Interaction between Pd atoms and the ZrC(001) support enhances reactivity and stability of the electrocatalyst, while preventing oxidation of the surface.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Evangelos Delikonstantis, Marco Scapinello, Varun Singh, Hilde Poelman, Cesare Montesano, Luca Matteo Martini, Paolo Tosi, Guy B. Marin, Kevin M. Van Geem, Vladimir V. Galvita, Georgios D. Stefanidis
Summary: We propose and demonstrate an integrated electrified plasma-assisted chemical looping (PACL) process that achieves supra-equilibrium CO2 conversions at temperatures below 3000 K. By dissociating CO2 into CO/O using plasma and using an oxygen scavenger downstream to capture produced oxygen species, high CO2 conversions are achieved even at low temperatures.
ACS ENERGY LETTERS
(2022)
Article
Chemistry, Physical
M. A. Krestyaninov, A. M. Kolker
Summary: In this study, the structure of pyrrolidone dimers and the hydrogen-bonded complexes of pyrrolidone with water molecules were investigated using quantum chemical methods. The analysis included geometric parameters, binding energies, atomic charges, and vibrational frequencies of hydrogen bonds. Additionally, calculations were conducted taking into consideration the water medium with the IEFPCM model.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Physical
Julie Heron, David Balcells
Summary: Copper-catalyzed azide-alkyne cycloaddition (CuAAC) is a versatile reaction in click chemistry, and this study using density functional theory (DFT) revealed a single concerted step mechanism for the reaction. The research also showed that the formation of 1,4-triazole isomer of the product is selective, highlighting the flexible nature of the bonding within the coordination sphere of the bimetallic core of the catalyst.
Article
Chemistry, Multidisciplinary
Edina Reizer, Bela Fiser
Summary: The reaction initiation points of the 16 priority polycyclic aromatic hydrocarbons (PAHs) have been determined by calculating the different C-H bond dissociation enthalpy (BDE) values. Six density functional theory methods and four basis sets were applied, and the most feasible combination was selected. Most of the hydrogen atoms are in zig-zag positions, and the BDE and bond length values for the PAHs range between certain values. The initiation points are mostly represented by armchair and peak hydrogens.
ARABIAN JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Julian A. Michaels, Lukas Janavicius, Xihang Wu, Clarence Chan, Hsieh-Chih Huang, Shunya Namiki, Munho Kim, Dane Sievers, Xiuling Li
Summary: This paper presents a plasma-free, open-circuit, photo-induced metal-assisted chemical etch method for fabricating micro and nanoscale features on Silicon carbide without causing high energy ion-related surface damage. The comprehensive exploration of parameter space demonstrates the controllability and versatility of this technique in producing ordered arrays of micro and nanoscale SiC structures with porous or solid sidewalls, while elucidating the etching mechanism.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Hyun-Hang Shin, Jaeyoung Jeong, Yeonsig Nam, Kang Sup Lee, Gyu Jin Yeon, Hankyul Lee, Seung Yeon Lee, Sangwon Park, Hyungjun Park, Jin Yong Lee, Zee Hwan Kim
Summary: Recent studies have found evidence that plasmon-excited nanostructures can induce non-thermal vibrational activation of metal-bound reactants. By analyzing the anti-Stokes Raman spectra, it was discovered that the vibrational mode of the reactant is selectively excited, resulting in more energy in the reactants than expected based on thermalized molecules at the given temperature. Additionally, a significant portion of the excited reactant is in vibrational overtone states with energies exceeding 0.5 eV. These findings validate the mechanism of plasmon-assisted chemical reactions and offer a new way to explore vibrational reaction control on metal surfaces.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Job J. C. Struijs, Valery Muravev, Marcel A. Verheijen, Emiel J. M. Hensen, Nikolay Kosinov
Summary: The catalytic conversion of CO2 to valuable chemicals is a promising solution to counteract the negative effects of increasing CO2 concentration. In this study, Co/CeO2 was explored as a catalyst for the methanation of diluted CO2 streams, showing excellent performance at low reaction temperatures and CO2 partial pressures. Mechanistic understanding of this activity was gained through in situ spectroscopic techniques, revealing the importance of the cobalt-ceria interface in enhancing catalytic activity.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
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
Chemistry, Applied
Shaojie Li, Xianxuan Ren, Brahim Mezari, Yujie Liu, Peerapol Pornsetmetakul, Anna Liutkova, Nikolay Kosinov, Emiel J. M. Hensen
Summary: Nanosized ZSM-5 zeolites with high acidity (Si/Al < 15) are advantageous catalysts for obtaining aromatics in C1 chemistry. However, synthesizing these nanosized zeolites in a cost-effective and scalable manner is challenging. In this study, nanosized ZSM-5 (20-50 nm) with high acidity (Si/Al = 11) was successfully synthesized using p-phenylenedimethylene-bis(tripropylammonium) dichloride as the sole organic structure-directing agent (OSDA). The nanosized ZSM-5 demonstrated enhanced aromatics formation compared to bulk ZSM-5 due to its high acidity and shortened diffusion paths in methanol dehydration and non-oxidative dehydroaromatization of methane reactions.
MICROPOROUS AND MESOPOROUS MATERIALS
(2023)
Article
Multidisciplinary Sciences
Valery Muravev, Alexander Parastaev, Yannis van den Bosch, Bianca Ligt, Nathalie Claes, Sara Bals, Nikolay Kosinov, Emiel J. M. Hensen
Summary: The size and structure of supported transition metals, which act as active sites, can be adjusted to optimize the catalytic performance of heterogeneous catalysts. In single-atom metal catalysts, the support itself has a significant impact on catalytic properties. In this study, we demonstrate that the size of the CeO2 support determines the reactivity of atomically dispersed Pd in CO oxidation. Small CeO2 nanocrystals (around 4 nanometers) show high activity in CO-rich conditions, while medium-sized CeO2 (around 8 nanometers) is preferred for lean conditions. Detailed spectroscopic investigations reveal size-dependent redox properties at the Pd-CeO2 interface.
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
Hao Zhang, Valery Muravev, Liang Liu, Anna Liutkova, Jerome F. M. Simons, Blanka Detlefs, Huaizhou Yang, Nikolay Kosinov, Emiel J. M. Hensen
Summary: Direct nonoxidative coupling is a promising route for methane upgrading, but lack of efficient catalysts hinders its commercialization. Recently, Pt/CeO2 catalysts with isolated Pt species have gained increasing attention. In this study, the catalytic role and evolution of isolated Pt centers on CeO2 prepared by flame spray pyrolysis under harsh reaction conditions of nonoxidative methane coupling were investigated. The isolated Pt sites sinter during the reaction at 800°C, resulting in a decrease in ethylene and ethane yield. However, the agglomerated Pt can be redispersed using an in situ regeneration strategy in oxygen. It was found that isolated Pt centers can only activate methane at the initial reaction stage, while the CePt5 alloy acts as the active phase in prolonged reaction.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Anna Liutkova, Victor Drozhzhin, Jason M. J. J. Heinrichs, Valentin Jestl, Angelina Evtushkova, Brahim Mezari, Alvaro Mayoral, Nikolay Kosinov, Emiel J. M. Hensen
Summary: The selectivity of the methanol-to-hydrocarbons reaction can be modified by using alkaline earth metals to modify zeolite catalysts. Sr2+ was used as a catalyst and its higher atomic number facilitated characterization by scanning transmission electron microscopy and operando X-ray absorption spectroscopy. The presence of Sr2+ in the zeolite micropores during the reaction resulted in an increased adsorption of reactants compared to zeolites without Sr, explaining the increased propylene yield and lower deactivation rate.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Jerome F. M. Simons, Ton J. de Heer, Rim C. J. van de Poll, Valery Muravev, Nikolay Kosinov, Emiel J. M. Hensen
Summary: This study investigates the structure sensitivity of CO2 hydrogenation on nickel nanoparticle catalysts and reveals the different characteristics of active sites for CO2 conversion to CO and subsequent hydrogenation to CH4. It demonstrates that the size of the nanoparticles affects the reaction steps differently, with smaller particles losing their methanation activity due to a lower availability of active sites.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Physics, Applied
Long Zhang, Jing Pan, Min Li, Ivo A. W. Filot, Emiel J. M. Hensen, Hui Wang
Summary: In this study, the structures and compositions of CeO2-supported Cu-based bimetallic clusters in an oxygen-rich environment were investigated using first-principles calculations, genetic algorithm, and grand canonical Monte Carlo methods. It was found that the catalytic activity and reaction mechanism of the oxide-supported alloy catalysts vary with the composition and oxidation state of the alloy nanocluster under the reaction conditions.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Physical
Francesco Cannizzaro, Sjoerd Kurstjens, Tom van den Berg, Emiel J. M. Hensen, Ivo A. W. Filot
Summary: Metal promoted indium oxide (In2O3) catalysts show promise for CO2 hydrogenation to methanol and carbon monoxide. The effect of metal dispersion on the methanol selectivity of In2O3 catalysts is debated, with the role of single metal atoms vs. metal clusters as catalysts being discussed. Density functional theory calculations were used to study the role of single atoms (SAs) of Ni, Pd, Pt, and Rh on In2O3(111) surface in CO2 hydrogenation to CO and methanol. Microkinetic simulations reveal that all SA models primarily catalyze CO formation through a redox pathway involving oxygen vacancies, explaining the negligible CH3OH selectivity due to higher barriers for formate intermediates hydrogenation compared to the overall barrier for the rWGS reaction.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Lulu Chen, Ivo A. W. Filot, Emiel J. M. Hensen
Summary: On CeO2, Ru-6 clusters are more active catalysts for CO2 methanation compared to single-atom Ru. Ru-6/RuCex-1O2x-1 shows a higher CO2 methanation rate due to lower activation energy for HCO dissociation.
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
Luke M. van Koppen, A. Iulian Dugulan, G. Leendert Bezemer, Emiel J. M. Hensen
Summary: This study explored the role of manganese as a structural promoter on silica-supported cobalt nanoparticles under high CO conversion conditions. It was found that adding manganese oxide enhanced the dispersion of cobalt but resulted in cobalt silicate formation. Without manganese, the cobalt particles sintered and transformed into cobalt carbide.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Anna Liutkova, Nikolay Kosinov, Emiel J. M. Hensen
Summary: Establishing structure-activity relationships is crucial for improving catalysts and reaction conditions in the methanol-to-hydrocarbons reaction. Modification of ZSM-5 catalyst with calcium increases selectivity to C3+ olefins, but decreases overall activity.
JOURNAL OF CATALYSIS
(2023)