Article
Chemistry, Physical
Anne V. Le, Biplab Rajbanshi, Raul F. Lobo, Peng Bai
Summary: In this study, DFT calculations were used to investigate the mechanisms of propene metathesis catalyzed by WOx/SiO2. The results showed that there are still many mechanisms of heterogeneous catalyzed metathesis reactions that are not well understood. The pseudo-Wittig mechanism was found to be the most favorable method for generating initial alkylidene active sites. The allylic and vinylic C-H activations are more difficult and require the reduction of surface sites to W(+4).
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Pratya Promchana, Kittisak Choojun, Wanwisa Limphirat, Yingyot Poo-arporn, Tawan Sooknoi
Summary: Acetylene in ethylene-rich feed can be removed via acetylene/ethylene cross-metathesis over WO3-supported catalysts at 450 degrees C, yielding 1,3-butadiene with cyclohexene as a minor product. The catalyst must be treated with ethylene at 600 degrees C to generate a genuinely active site of tungsten (IV) alkylidene species (W=CH2). The H2 treatment decreases surface W--O concentration, and hence the activity.
APPLIED CATALYSIS A-GENERAL
(2023)
Article
Energy & Fuels
Elif Muslu, Esin Eren, Aysegul Uygun Oksuz
Summary: This study investigates the potential of a tungsten oxide/silicon dioxide/tungsten oxide (WO3/SiO2/WO3) thin film as a flexible electrode for supercapacitors. The film combines the high specific capacitance and electrochemical stability of WO3 with the mechanical durability and high surface area of SiO2. The film's pseudocapacitive behavior, facilitated by the SiO2 interlayer, enables adjustment of electrolyte ions, leading to high specific capacitances and demonstrating its potential for supercapacitor applications. This research contributes to the development of efficient and environmentally friendly energy storage solutions.
Article
Materials Science, Multidisciplinary
Ander Diego-Lopez, Oscar Cabezuelo, Alejandro Vidal-Moya, M. Luisa Marin, Francisco Bosca
Summary: A new optimized photocatalyst with SiO2 as a supporting substrate and a shell of WO3 nanoparticles decorated with Fe3O4 nanocrystals has been developed for wastewater remediation at neutral pH. Its photocatalytic activity was evaluated on the photodegradation of methylene blue (MB) and diclofenac (DCF), and the generation of .OH was proven to be responsible for the oxidation processes. The synergistic effect between Fe3O4 and WO3 in the presence of light and H2O2 enhances the generation of .OH.
APPLIED MATERIALS TODAY
(2023)
Article
Chemistry, Inorganic & Nuclear
Takeshi Matsukawa, Toru Ishigaki
Summary: The study investigated the crystallographic changes of monoclinic WO3 powder samples under different reduction conditions using X-ray and neutron diffraction measurements. The results showed that the formation of various oxygen-deficient structures, including stoichiometric WO3-x, non-stoichiometric WO3-x, and W metal, during hydrogen treatment. Neutron powder diffraction measurements revealed that the reduction of WO3 under hydrogen occurred on the surface, enhancing the knowledge in the chemical and physical properties of WO3-x.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Physical
Istvan Szekely, Endre-Zsolt Kedves, Zsolt Pap, Monica Baia
Summary: This study provides meaningful insights into the synthesis design of WO3 materials by systematically altering precursors and shaping agents. The presence of W+5 centers was confirmed, with W+5 and W+6 species affecting the band gap values and photoactivity of the composites. The electronegativity of the halide anions has both favorable and unfavorable effects on the photoactivity of the composites.
Article
Nanoscience & Nanotechnology
Chiara Nomellini, Annalisa Polo, Camilo A. Mesa, Ernest Pastor, Gianluigi Marra, Ivan Grigioni, Maria Vittoria Dozzi, Sixto Gimenez, Elena Selli
Summary: The performance of composite WO3/BiVO4 photoanodes can be improved by nanostructuring the WO3 underlayer, mitigating charge transport and recombination issues.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Applied
Nattaphon Hongrutai, Sutasinee Watmanee, Tanaya Srisakwattana, Sippakorn Wannakao, Piyasan Praserthdam, Joongjai Panpranot
Summary: The propene self-metathesis and the secondary metathesis of 1-butene over tungsten-based catalysts supported on silica and 1%Al-doped SiO2 were investigated. Incorporating WOx improved tungsten dispersion and formation of active tetrahedral WOx species on pure SiO2, while negative effects were observed when tungsten was incorporated in the 1%Al-doped SiO2. The abundance of Bronsted and Lewis acid species was found to be more important than surface silanol and the presence of tetrahedral tungsten oxide species in these reactions.
Article
Materials Science, Coatings & Films
Kamesh Mullapudi, Konner E. K. Holden, Jessica L. Peterson, Charles L. Dezelah, Daniel F. Moser, Ravindra K. Kanjolia, Douglas J. Tweet, John F. Conley
Summary: For the first time, tungsten oxide-silicon dioxide (WOx-SiOy) composite thin films were deposited using remote oxygen plasma-enhanced atomic layer deposition (ALD) with a novel heteronuclear and heteroleptic precursor, bis(tert-butylimido)bis(trimethylsilylmethyl)tungsten. The ALD growth was self-limiting in a temperature window of 203-328 degrees C, with growth per cycle decreasing as temperature increased. The film composition and properties varied with deposition temperature, including the reduction of carbon impurity content, an increase in refractive index and density, and a decrease in optical bandgap. Upon annealing, the films crystallized into the triclinic WO3 phase.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Materials Science, Multidisciplinary
Dong Liang, Sang Xiong, Xiaomeng Zhang, Yuanfeng Ye, Jingxin Cao, Xingxing Hu, Yao Song, Qianwen Wei
Summary: WO3:Eu3+ powder was prepared using the microemulsion method and coated with SiO2 using a coating method. The resulting WO3:Eu3+@ SiO2 nanocomposites with core-shell structure were characterized for their structure, morphology, and luminescence properties. The nanocomposites showed spherical and granular morphology with an average particle size below 100 nm. The strongest luminescence intensity was observed at a water-alcohol ratio of 1:3, with an excitation wavelength of 328 nm.
BULLETIN OF MATERIALS SCIENCE
(2023)
Review
Chemistry, Multidisciplinary
Solene Morand, Philippe Jubault, Jean-Philippe Bouillon, Samuel Couve-Bonnaire
Summary: This review presents an overview of the syntheses of gem-heteroatom-substituted fluoroalkenes over the past decade, covering various common heteroatoms and their potential applications in mimicking important organic functions.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Energy & Fuels
M. F. Al-Kuhaili
Summary: Multilayer thin films are used as functional coatings in various applications, such as transparent conducting electrodes and infrared-blocking energy-saving coatings. This study investigated the properties of WO3/Ag/WO3 multilayer coatings, which were optimized to meet the requirements of both applications. The results showed that these coatings exhibited high electrical conductivity, visible transmittance, and infrared-blocking performance.
Article
Engineering, Electrical & Electronic
Aditya Yadav, Lalit Goswami, Pargam Vashishtha, Anuj Sharma, Preeti Goswami, Govind Gupta
Summary: This report presents the synthesis of WO3 film with nano-island surface morphology using DC magnetron sputtering and explores its applications in optoelectronics. The fabricated film exhibits high responsivity and excellent performance parameters, indicating its potential for broadband light detection.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Chemistry, Physical
Biborka Boga, Istvan Szekely, Monica Focsan, Monica Baia, Tibor Szabo, Laszlo Nagy, Zsolt Pap
Summary: In this study, vectorial electron transfer between reaction center protein (RC) and WO3(center dot 0.33H2O) was achieved through physical adsorption, with the interaction efficiency being correlated to surface charge, structural/morphological properties, and anchoring capacity of the inorganic carrier. Additionally, the role of WO3(center dot 0.33H2O) as an electron trap and charge separator was demonstrated not only in RCs/WO3(center dot 0.33H2O) biohybrid systems but also in TiO2/WO3(center dot 0.33H2O) composites.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Valentin Diez-Cabanes, Aprimengel Morales-Garcia, Francesc Illas, Mariachiara Pastore
Summary: Semiconducting heterojunction-based devices using transition metal oxides like tungsten (WO3) and titanium (TiO2) exhibit the best photocatalytic performance currently, due to the ability to optimize electron/hole injection barriers through size, morphology, and composition adjustments. However, this approach requires a deep understanding of structure-property relationships that are difficult to access through experiments.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Electrochemistry
Matej Zlatar, Darryl Nater, Daniel Escalera-Lopez, Rani Mary Joy, Paulius Pobedinskas, Ken Haenen, Christophe Coperet, Serhiy Cherevko
Summary: Single-atom catalysts (SACs) have shown improved electrocatalytic performance in various industrially relevant reactions, including oxygen evolution reaction (OER). However, the stability of SACs has received little attention in the literature. In this study, we evaluate the stability of Ir SAC and highly dispersed Ru catalysts supported by indium doped tin oxide (ITO) using online inductively coupled plasma mass spectrometry setup (online ICP-MS). We find that these catalysts exhibit high activity but lower stability, and propose that the change in OER mechanism from adsorbate evolution mechanism (AEM) to lattice oxygen mechanism (LOM) with participation of the support contributes to their lower stability.
ELECTROCHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Anna Giorgia Nobile, David Trummer, Zachariah J. Berkson, Michael Worle, Christophe Coperet, Pierre-Adrien Payard
Summary: The structure of the surface sites of the Union Carbide ethylene polymerization catalyst remains elusive, but recent research suggests the presence of monomeric and dimeric Cr(ii) sites, as well as Cr(iii) hydride sites. However, the analysis of their structure is complicated by large paramagnetic H-1 shifts induced by unpaired electrons on the Cr atoms. In this study, a cost-efficient DFT methodology was implemented to calculate the H-1 chemical shifts for antiferromagnetically coupled metal dimeric sites, allowing for the assignment of observed H-1 shifts for the industrial-like UC catalyst and confirming the presence of monomeric and dimeric Cr(ii) sites as well as dimeric Cr(iii)-hydride sites.
Article
Chemistry, Multidisciplinary
Moritz Bernhardt, Maciej D. D. Korzynski, Zachariah J. J. Berkson, Fabrice Pointillart, Boris Le Guennic, Olivier Cador, Christophe Coperet
Summary: Generating or retaining slow magnetic relaxation in surface-immobilized single-molecule magnets (SMMs) from molecular precursors is a challenging task. However, a material with SMM characteristics has been successfully generated by chemisorption of (Cp-ttt)(2)DyCl on a silica surface containing tailored Lewis acidic Al-(III) sites. Detailed studies reveal slow magnetic relaxation up to 51 K, hysteresis up to 8 K, and an effective energy barrier (U (eff)) of 449 cm(-1), the highest reported for a supported SMM.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Scott R. Docherty, Olga Safonova, Christophe Coperet
Summary: This study investigates the active state of Au-Zn catalysts for CO2 hydrogenation to methanol. Silica-supported bimetallic Au-Zn alloys, prepared by surface organometallic chemistry (SOMC), are shown to be efficient catalysts for CO2 hydrogenation to methanol. In situ X-ray absorption spectroscopy (XAS), together with gas-switching experiments, amplifies subtle changes occurring at the surface of the catalyst. Multivariate curve resolution alternating least-squares (MCR-ALS) analysis identifies an Au-Zn alloy and reveals its reversible redox changes under reaction conditions. These findings highlight the role of alloying and dealloying in Au-based CO2 hydrogenation catalysts and the significance of reversible processes in driving reactivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Wangyang Wang, Wei Zhou, Yuchen Tang, Weicheng Cao, Scott R. Docherty, Fangwei Wu, Kang Cheng, Qinghong Zhang, Christophe Coperet, Ye Wang
Summary: Gold nanoparticles dispersed on mordenite efficiently catalyze the selective oxidation of methane to methanol by molecular oxygen in aqueous medium in the presence of carbon monoxide. The methanol productivity reaches 1300 mu mol g(cat) (-1) h(-1) or 280 mmol g(Au) (-1) h(-1) with 75% selectivity at 150 degrees C, outperforming most catalysts reported under comparable conditions. Both hydroxyl radicals and hydroperoxide species participate in the activation and conversion of methane, while the lower affinity of methanol on gold mainly accounts for higher methanol selectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Terry Z. H. Gani, Zachariah J. Berkson, Ran Zhu, Jong Hun Kang, John R. Di Iorio, Ka Wing Chan, Daniel F. Consoli, Sohel K. Shaikh, Christophe Coperet, Yuriy Roman-Leshkov
Summary: The authors identify a dynamic site renewal and decay cycle, mediated by proton transfers involving proximal BrOnsted acidic OH groups, which operates concurrently with the Chauvin cycle and could address roadblocks associated with industrial metathesis processes. This cycle can be manipulated using small quantities of promoter olefins to drastically increase steady-state propylene metathesis rates, with negligible promoter consumption, showing potential applicability to other reactions. The increase in activity and reduction of operating temperature requirements were also observed on MoOx/SiO2 catalysts, indicating the broad scope of this strategy in addressing major challenges in industrial metathesis processes.
Article
Chemistry, Multidisciplinary
Weicheng Cao, Alexander Yakimov, Xudong Qian, Jiongzhao Li, Xiaogang Peng, Xueqian Kong, Christophe Coperet
Summary: A strategy based on detecting NMR signatures of 113Cd, 77Se, and 15N augmented with DFT modeling was developed to investigate the interaction between amine ligands and CdSe nanocrystals (NCs). The results showed that amine ligands not only directly bond to surface sites, but also interact through hydrogen bonding with absorbed water. This study provides molecular-level insight into the surface properties of amine-capped CdSe NCs and lays the foundation for designing colloidal NCs with tailored properties.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Daniel F. Abbott, Yuan-Zi Xu, Denis A. Kuznetsov, Priyank Kumar, Christoph R. Mueller, Alexey Fedorov, Victor Mougel
Summary: In this study, the catalytic activity of a Fe-substituted two-dimensional molybdenum carbide in nitrate reduction reaction (NO3RR) was investigated. The results showed that the catalyst exhibited high efficiency in both acidic and neutral media. The formation of surface oxygen vacancies promoted by Fe sites was identified as the active sites for NO3RR, similar to the mechanism of natural Mo-based nitrate reductase enzymes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Hui Zhou, Scott R. Docherty, Nat Phongprueksathat, Zixuan Chen, Andrey V. Bukhtiyarov, Igor P. Prosvirin, Olga V. Safonova, Atsushi Urakawa, Christophe Coperet, Christoph R. Muller, Alexey Fedorov
Summary: A Cu-Zn/SiO2 catalyst was developed for the efficient and selective hydrogenation of CO2 to methanol. The optimized catalyst exhibited an intrinsic methanol formation rate of 4.3 g h(-1) g(Cu) (-1) and a selectivity to methanol of 83% at 230 degrees C and 25 bar.
Article
Chemistry, Physical
Zixuan Chen, Alexander I. Serykh, Agnieszka Kierzkowska, David Gajan, Scott R. Docherty, Alexander V. Yakimov, Paula M. Abdala, Christophe Coperet, Pierre Florian, Alexey Fedorov, Christoph R. Mueller
Summary: In this study, we utilized atomic layer deposition to engineer a model PDH catalyst and found that the structural dynamics of surface sites vary with the degree of hydroxylation. The high-performance PDH catalyst possesses isolated tetracoordinate Ga-[4]((4Si)) sites.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Enzo Brack, Milivoj Plodinec, Marc-Georg Willinger, Christophe Coperet
Summary: Propane dehydrogenation is a key technology and Pt-based catalysts with Ga promoter have been investigated. However, experimental evidence is lacking due to the use of oxide supports. In this study, a methodology was developed to generate Pt and PtGa nanoparticles on carbon supports with tailored interfaces. The introduction of Ga enables the formation of homogenously alloyed, amorphous PtGa nanoparticles, while the presence of an oxide interface stabilizes the formation of small particles.
Article
Chemistry, Multidisciplinary
Scott R. Docherty, Philipp Scharz, Domenico Gioffre, Alexander V. Yakimov, Christophe Coperet
Summary: This study investigates the structure of silica-supported zirconium hydrides using deuterium solid state nuclear magnetic resonance spectroscopy as an example of supported metal hydrides. These metal hydrides have notable reactivity towards small molecules and can activate both C-H and C-C bonds, making them useful in hydrocarbon conversion.
HELVETICA CHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Anton Ashuiev, Anna Giorgia Nobile, David Trummer, Daniel Klose, Sergey Guda, Olga V. Safonova, Christophe Coperet, Alexander Guda, Gunnar Jeschke
Summary: This study investigates the electronic structure of well-defined silica-supported Cr(III) alkyls using a combination of surface organometallic chemistry, EPR spectroscopy, and machine learning-supported XAS studies. Results show the presence of different surface species in high and low-spin states, associated with different coordination environments. The low-spin Cr(III) sites are shown to participate in ethylene polymerization, suggesting their potential involvement in the Phillips catalyst.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Sebastian Sabisch, Yuya Kakiuchi, Scott R. Docherty, Alexander V. Yakimov, Christophe Coperet
Summary: The structure of surface sites in Ziegler-Natta catalysts, which are crucial for the production of polyethylene and polypropylene, has long been a mystery. This study uses solid-state NMR spectroscopy to investigate the structure of VOCl3 on MgCl2(thf)(1.5) and reveals the influence of inorganic reactants on the surface structure. The findings provide valuable information about the coordination sphere and the effect of the support morphology on surface site structures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Xiaoyu Zhou, Gregory A. Price, Glenn J. Sunley, Christophe Coperet
Summary: This study synthesized cobalt nanoparticles with different sizes through surface organometallic chemistry and found that under CO2 hydrogenation conditions, smaller particles mainly catalyzed the reverse water-gas shift reaction, while larger particles were more favorable for methanation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)