jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Na Wang | Zhong Shen | Wang Luo | Hua‐Kai Li | Ze‐Jiang Xu | Chao Shi | Heng‐Yun Ye | Shuai Dong | Le‐Ping Miao
Source: Nature Communications (preprint, 2024-11-26)
Field: Materials Science — Materials Chemistry

Noncollinear ferroelectric and screw-type antiferroelectric phases in a metal-free hybrid molecular crystal Noncollinear dipole textures greatly extend the scientific merits and application perspective of ferroic materials. In fact, noncollinear spin textures have been well recognized as one of the core issues of condensed matter, e.g. cycloidal/conical magnets with multiferroicity and magnetic skyrmions with topological properties. However, the counterparts in electrical polarized materials are less studied and thus urgently needed, since electric dipoles are usually aligned collinearly in most ferroelectrics/antiferroelectrics. Molecular crystals with electric dipoles provide a rich ore to explore the noncollinear polarity. Here we report an organic salt (H<sub>2</sub>Dabco)BrClO<sub>4</sub> (H<sub>2</sub>Dabco = N,N'-1,4-diazabicyclo[2.2.2]octonium) that shows a transition between the ferroelectric and antiferroelectric phases. Based on experimental characterizations and ab initio calculations, it is found that its electric dipoles present nontrivial noncollinear textures with 60<sup>o</sup>-twisting angle between the neighbors. Then the ferroelectric-antiferroelectric transition can be understood as the coding of twisting angle sequence. Our study reveals the unique science of noncollinear electric polarity. Antiferroelectricity ; Ferroelectricity ; Materials science ; Type (biology) ; Metal ; Crystallography ; Crystal (programming language) ; Chemistry ; Optoelectronics ; Metallurgy ; Geology ; Dielectric ; Computer science Solid-state spectroscopy and crystallography ; Nonlinear Optical Materials Research ; Acoustic Wave Resonator Technologies
Authors: Juba Salhi | Michele Mattera | Imad Arfaoui | Jan Patrick Calupitan | Sandra Alvès | Claire Troufflard | Céline Paris | Guillaume Izzet | Anna Proust | David Kréher | G. Simon | Alexandre Dazzi | Florence Volatron
Source: Communications Chemistry (article, 2024-12-19)
Field: Materials Science — Materials Chemistry

Single polyoxometalate-based nanoclusters characterized by infrared absorption nanospectroscopy Bottom-up engineering is a very attractive field. However, the periodic organization of molecules on a solid substrate is challenging, particularly in the selection of the appropriate characterization technique which is suitable for both large area and accurate analysis at the nanoscale. Here, this study demonstrates the unambiguous identification of complex molecular layers by infrared absorption microscopy at the nanometric scale. This technique allowed for the direct observation of the presence of isolated polyoxometalate-based nanoclusters dispersed all over a substrate. Nanoclusters ; Polyoxometalate ; Characterization (materials science) ; Materials science ; Substrate (aquarium) ; Infrared ; Nanoscopic scale ; Absorption (acoustics) ; Nanotechnology ; Infrared spectroscopy ; Chemistry ; Optics ; Catalysis ; Physics ; Organic chemistry Nanocluster Synthesis and Applications ; Surface Chemistry and Catalysis ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Warot Prasanseang | Narasiri Maineawklang | Natthawoot Liwatthananukul | Supattra Somsri | Chularat Wattanakit
Source: ChemPhysChem (article, 2024-12-10)
Field: Materials Science — Materials Chemistry

Synthesis, Characterization, and CO<sub>2</sub> Methanation Over Hierarchical ZSM‐5‐NiCoAl Layered Double Hydroxide Nanocomposites: Improvement of C−C Coupling to Ethane To date, preparing materials with highly dispersed metal nanoparticles without metal agglomeration on a solid support is challenging. This work presents an alternative approach for synthesizing NiCo species on hierarchical ZSM-5 materials derived from a ZSM-5@NiCoAl-LDHs composite. The designed material was prepared by the growth of a NiCo-layered double hydroxides (LDHs) precursor on the surface of hierarchical ZSM-5 nanosheets. The effect of the weight ratio of NiCo-LDHs precursor to ZSM-5 on the composite properties has been studied. The results show that 45 wt.% LDHs (ZSM-5@NiCoAl-LDHs-45) is the most suitable condition for preparing NiCoAl-LDHs/ZSM-5 composite, which promotes a strong interaction between bimetallic NiCo and hierarchical ZSM-5. The ZSM-5@NiCoAl-LDHs-45 showed a BET surface of 386 m<sup>2</sup> g<sup>-1</sup>, in which the surface area has been re-allocated between microspores and mesopores due to the presence of NiCoAl-LDHs composite. The catalyst was also tested for CO<sub>2</sub> methanation at 380 °C under atmospheric hydrogen pressure. The results show that the catalyst could provide CO<sub>2</sub> conversion of up to 40 % at WSHV of 2.91 h<sup>-1</sup>. Interestingly, it could not only promote methane but also provide a high selectivity of ethane, approximately 20.4 %. Moreover, the excellent catalytic stability of ethane production was illustrated over 24 hours of time-on-stream (TOS). Bimetallic strip ; Materials science ; Catalysis ; Chemical engineering ; Methanation ; Nanocomposite ; Layered double hydroxides ; ZSM-5 ; Composite number ; Mesoporous material ; Specific surface area ; Hydrogen production ; Zeolite ; Nanotechnology ; Composite material ; Chemistry ; Organic chemistry Layered Double Hydroxides Synthesis and Applications ; Catalysts for Methane Reforming ; Carbon dioxide utilization in catalysis
Authors: Olia Bouzid | Daniel Martínez-Fernández | Miguel Herranz | Nikos Ch. Karayiannis
Source: Preprints.org (preprint, 2024-07-10)
Field: Materials Science — Materials Chemistry

Entropy-Driven Crystallization of Hard Colloidal Mixtures of Polymers and Monomers The self-assembly is an intriguing process of great importance in general soft matter and thus re-ceives an ever-growing scientific interest. Its most trivial example is the entropy-driven crystalli-zation of hard spheres. Past works have established the similarities and differences in the phase behavior of monomers and chains made of hard spheres. In the present work, inspired by the dif-ference in the melting points of the pure components, we study, through Monte Carlo simulations, the phase behavior of athermal mixtures composed of fully flexible polymers and individual monomers of uniform size. We analyze how the relative number fraction and the packing density affect crystallization and the established ordered morphologies. A synergetic effect is observed in the crystallization leading to synchronous crystallization of the two species. Structural analysis of the resulting ordered morphologies shows perfect mixing and thus no phase separation, which could split the system into polymer-rich and monomer-rich domains. Due to the constraints imposed by chain connectivity, the local environment of the individual spheres is systematically more spherical and more symmetric compared to the one of spheres belonging to chains. In general, increasing polymer content leads to reduction of the degree of crystallinity. According to the present findings, relative concentration is another determining factor to control the phase behavior of hard colloidal systems based on polymers. Crystallization ; Hard spheres ; Polymer ; Materials science ; Monomer ; Crystallinity ; SPHERES ; Chemical physics ; Colloid ; Atomic packing factor ; Volume fraction ; Phase (matter) ; Crystallization of polymers ; Monte Carlo method ; Entropy (arrow of time) ; Thermodynamics ; Statistical physics ; Crystallography ; Chemistry ; Physics ; Mathematics ; Physical chemistry Material Dynamics and Properties ; Phase Equilibria and Thermodynamics ; Polymer crystallization and properties
Authors: Gireeshkumar Balakrishnan | Marli Miriam de Souza Lima | Frédérick Niepceron | Olivier Colombani | Taco Nicolaï | Christophe Chassenieux
Source: Soft Matter (article, 2024-01-01)
Field: Chemistry — Organic Chemistry

pH-controlled breakup of fractal aggregates, microgels and gels formed by self-assembled amphiphilic triblock copolymers The degradation of (micro)gels and aggregates based on self-assembled triblock copolymers was induced by increasing pH. It is controlled by the escape time of the end blocks with a rate that varied by several orders of magnitude by varying the pH. Copolymer ; Amphiphile ; Breakup ; Chemical engineering ; Materials science ; Polymer chemistry ; Fractal ; Chemistry ; Polymer ; Composite material Surfactants and Colloidal Systems ; Advanced Polymer Synthesis and Characterization ; Hydrogels: synthesis, properties, applications
Authors: Maria Meledina | Dileep Krishnan | Daen Jannis | Maarten Wirix | Xiaochao Wu | Ulrich Simon | Sorin Lazar | Peter Tiemeijer | Paolo Longo
Source: BIO Web of Conferences (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Multimodal and multidimensional EELS and EDX for investigations of catalysts at the nanoscale Nanoscopic scale ; Nanotechnology ; Materials science ; Catalysis ; Scale (ratio) ; Computer science ; Chemistry ; Geography ; Cartography Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions ; Machine Learning in Materials Science
Authors: Ohsung Kwon | E. Zeynep Ayla | David S. Potts | David W. Flaherty
Source: Angewandte Chemie (article, 2024-05-13)
Field: Chemistry — Inorganic Chemistry

Influence of Ti‐incorporated Zeolite Topology and Pore Condensation on Vapor Phase Propylene Epoxidation Kinetics with Gaseous H<sub>2</sub>O<sub>2</sub> Abstract Vapor‐phase propylene (C 3 H 6 ) epoxidation kinetics with hydrogen peroxide (H 2 O 2 ) strongly reflects the physical properties of Ti‐incorporated zeolite catalysts and the presence of spectating molecules (“solvent”) near active sites even without a bulk liquid phase. Steady‐state turnover rates of C 3 H 6 epoxidation and product selectivities vary by orders of magnitudes, depending on the zeolite silanol ((SiOH) x ) density, pore topology (MFI, *BEA, FAU), and the quantity of condensed acetonitrile (CH 3 CN) molecules nearby active sites, under identical reaction mechanisms sharing activated H 2 O 2 intermediates on Ti surfaces. Individual kinetic analyses for propylene oxide (PO) ring‐opening, homogeneous diol oxidative cleavage, and homogeneous aldehyde oxidation reveal that secondary reaction kinetics following C 3 H 6 epoxidation responds more sensitively to the changes in zeolite physical properties and pore condensation with CH 3 CN. Thus, higher PO selectivities achieved in hydrophilic Ti‐MFI at steady‐state reflect the preferential stabilization of transition states for C 3 H 6 epoxidation (a primary reaction) relative to PO ring‐opening and oxidative cleavage (secondary reactions) that solvation effects that reflect interactions among condensed CH 3 CN within pores and the extended pore structure. Chemistry ; Zeolite ; Catalysis ; Propylene oxide ; Silanol ; Kinetics ; Molecule ; Solvent ; Physical chemistry ; Inorganic chemistry ; Photochemistry ; Organic chemistry Zeolite Catalysis and Synthesis ; Catalytic Processes in Materials Science ; Mesoporous Materials and Catalysis
Authors: Deniz Vardar | Stéphania Abdallah | Rana Mhanna | Prescillia Nicolas | Ahmet Dok | Yovan de Coene | Stijn Van Cleuvenbergen | Olivier Jeannin | Jean‐Pierre Malval | Thierry Verbiest | Koen Clays | Nathalie Bellec | Belkis Bilgin‐Eran | Franck Camerel | H. Akdas
Source: Dyes and Pigments (article, 2024-07-18)
Field: Materials Science — Materials Chemistry

Smart design of highly luminescent octupolar mesogenic tetra styryl-alkynyl bipyrimidine-based chromophores presenting non-linear optical properties The research investigations reported in this paper focuses on the influence of rational design on the photophysical properties of new all-organic multifunctional chromophores . Nonlinear optical (NLO) behavior, optical properties and mesogenicity of several new π-conjugated octupolar chromophores, presenting alkoxy styryl-alkynyl donor groups carrying aliphatic achiral and chiral chains in the 3,4/3,5/2,4 position, connected to electron-accepting 2,2-bipyrimidine cores are investigated by various techniques (light-transmission measurements, polarized-light optical microscopy , differential scanning calorimetry measurements, two-photon excited fluorescence and Hyper Rayleigh Scattering). The mesogenic properties were investigated depending on the position of the alkoxy chain and the 3,4 derivatives were found to exhibit liquid-crystal properties with the formation columnar phases over large temperature ranges which were confirmed by small-angle X-ray scattering analysis. All the molecules exhibit exceptional high fluorescence quantum yields values around 80 % and excellent nonlinear optical properties . Smart design of 3D π-conjugated octupolar organic materials with self-organizing properties which allows the emergence of highly luminescent multifunctional liquid crystalline chromophores exhibiting quantum yields and displaying very good second and cubic NLO activities. The crucial efficient transfer of chirality from molecule to supramolecular material lead to non-centrosymmetric organization resulting in a strong Second Harmonic Generation at the solid state. • Multifunctional derivatives exhibiting strong mesogenic, fluorescence and properties as well as large cubic and quadratic NLO responses. • Chromophores are extremely emissive with quantum yields (Φfluo.) around 80 % and displaying at the same time interesting second and cubic NLO activities. • Increasing the effective conjugation length within each D-π−A branch of the octupoles results in a substantial enhancement of their 2 PA performance. • Chirality lead to non-centrosymmetric organization resulting in a strong SHG at the solid state. Tetra ; Chromophore ; Mesogen ; Luminescence ; Polymer chemistry ; Materials science ; Nonlinear optical ; Photochemistry ; Chemistry ; Liquid crystalline ; Optoelectronics ; Liquid crystal ; Nonlinear system ; Medicinal chemistry ; Physics Luminescence and Fluorescent Materials ; Liquid Crystal Research Advancements ; Porphyrin and Phthalocyanine Chemistry
Authors: Priyanka Sharma | Abdurrahman Bilican | Wolfgang Schmidt | Olof Gutowski | Ann‐Christin Dippel | Kimberley Matschuk | Lukas Kopietz | Claudia Weidenthaler
Source: Batteries & Supercaps (article, 2024-08-23)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Carbon Xerogel as a Novel Minor Conductive Filler for Carbon‐Polymer Composite Bipolar Plates Abstract The current research explores the potential of carbon xerogel as a conductive filler in bipolar plates. The composites comprise graphite as the primary conductive filler and polypropylene as the binder. Carbon xerogel is introduced as a minor conductive filler, and its performance is compared with commercial carbon black. Both nanocarbons exhibit resemblances in microstructure, texture, and surface carbon chemistry. Through‐plane conductivity measurements reveal enhanced electrical conductivity upon replacing a fraction of graphite with either nanofiller. Cross‐sectional analyses of the plates employing computed tomography based on X‐ray diffraction and phase contrasts indicate that the observed electrical conductivity difference stems from reduced trapped air during production and the distribution of the minor filler particles. Given the similarities between carbon xerogel and the reference nanofiller, this study introduces the innovative concept of employing carbon xerogel as a filler for conductive bipolar plates. Carbon black ; Materials science ; Graphite ; Composite material ; Electrical conductor ; Filler (materials) ; Carbon fibers ; Conductivity ; Composite number ; Microstructure ; Carbon nanotube ; Polypropylene ; Texture (cosmology) ; Electrical resistivity and conductivity ; Chemistry ; Natural rubber Supercapacitor Materials and Fabrication ; Advanced Sensor and Energy Harvesting Materials ; Advanced Battery Technologies Research
Authors: Hanan H. Ibrahim | Timo Weckman | Dmitry Yu. Murzin | Karoliina Honkala
Source: ChemRxiv (preprint, 2024-01-04)
Field: Chemistry — Organic Chemistry

Understanding Selective Hydrogenation of Phenylacetylene on PdAg Single Atom Alloy: DFT Insights on Molecule Size and Surface Ensemble Effects Single atom alloys (SAA) have proven to be effective catalysts, offering customizable properties for diverse chemical processes. Various metal combinations are used in SAAs and Pd dispersed materials are frequently employed in catalyzing hydrogenation reactions. Herein, we explore the hydrogenation of phenylacetylene to styrene and ethylbenzene on PdAg SAA using density functional theory calculations. Our results show that while PdAg SAA does improve the activity of the host Ag towards hydrogenation, a dilute PdAg SAA surface with isolated Pd-atoms is not selective towards partial hydrogenation of phenylacetylene. Additionally, we investigate how the size of the reactant molecule, the size of the metal alloy ensemble, and a ligand effect impact the hydrogenation process. The SAA enhances the binding strengths of various organic adsorbates, although this effect diminishes as the adsorbate size increases. Our findings indicate the dilute PdAg exhibits selectivity towards hydrogenation of smaller molecules such acetylene due to its distinct adsorption geometry. The selective hydrogenation of phenylacetylene necessitates a surface Pd dimer ensemble. Our research highlights the importance of both reactant molecule size and surface configurations in SAA catalysts. This is particularly crucial when dealing with the adsorption of sizable organic molecules where the functional group can adopt different adsorption modes. Phenylacetylene ; Density functional theory ; Catalysis ; Adsorption ; Molecule ; Selectivity ; Acetylene ; Ethylbenzene ; Styrene ; Photochemistry ; Chemistry ; Binding energy ; Metal ; Atom (system on chip) ; Computational chemistry ; Materials science ; Inorganic chemistry ; Physical chemistry ; Organic chemistry ; Copolymer Nanomaterials for catalytic reactions ; Electrocatalysts for Energy Conversion ; Catalysis for Biomass Conversion
Authors: Darya O. Prima | Natalia S. Kulikovskaya | Роман А. Новиков | Alexander Yu. Kostyukovich | Julia V. Burykina | Victor M. Chernyshev | Valentine P. Ananikov
Source: Angewandte Chemie (article, 2024-04-04)
Field: Chemistry — Organic Chemistry

Revealing the Mechanism of Combining Best Properties of Homogeneous and Heterogeneous Catalysis in Hybrid Pd/NHC Systems Abstract The formation of transient hybrid nanoscale metal species from homogeneous molecular precatalysts has been demonstrated by in situ NMR studies of catalytic reactions involving transition metals with N ‐heterocyclic carbene ligands (M/NHC). These hybrid structures provide benefits of both molecular complexes and nanoparticles, enhancing the activity, selectivity, flexibility, and regulation of active species. However, they are challenging to identify experimentally due to the unsuitability of standard methods used for homogeneous or heterogeneous catalysis. Utilizing a sophisticated solid‐state NMR technique, we provide evidence for the formation of NHC‐ligated catalytically active Pd nanoparticles (PdNPs) from Pd/NHC complexes during catalysis. The coordination of NHCs via C (NHC) −Pd bonding to the metal surface was first confirmed by observing the Knight shift in the 13 C NMR spectrum of the frozen reaction mixture. Computational modeling revealed that as little as few NHC ligands are sufficient for complete ligation of the surface of the formed PdNPs. Catalytic experiments combined with in situ NMR studies confirmed the significant effect of surface covalently bound NHC ligands on the catalytic properties of the PdNPs formed by decomposition of the Pd/NHC complexes. This observation shows the crucial influence of NHC ligands on the activity and stability of nanoparticulate catalytic systems. Homogeneous ; Homogeneous catalysis ; Catalysis ; Mechanism (biology) ; Chemistry ; Heterogeneous catalysis ; Combinatorial chemistry ; Nanotechnology ; Computational chemistry ; Materials science ; Organic chemistry ; Physics ; Thermodynamics N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Catalytic Cross-Coupling Reactions ; Asymmetric Hydrogenation and Catalysis
Authors: Lukhanyo Dasi | Eric C. Hosten | Richard Betz
Source: IUCrData (article, 2024-01-05)
Field: Chemistry — Inorganic Chemistry

<i>rac</i>-Hydroxyisovaleric acid The title compound (systematic name: <i>rac</i>-2-hydroxy-3-methylbutanoic acid), C<sub>5</sub>H<sub>10</sub>O<sub>3</sub>, is the constitutional isomer of α-hy-droxy-butanoic acid. In the crystal, hydrogen bonds involving the alcoholic hydroxyl group give rise to centrosymmetric dimers that are extended to sheets perpendicular to the crystallographic <i>c</i> axis. Chemistry ; Crystal structure ; Hydrogen bond ; Crystallography ; Stereochemistry ; Group (periodic table) ; Molecule ; Organic chemistry Crystal structures of chemical compounds ; Radioactive element chemistry and processing ; Crystallography and molecular interactions
Authors: Tzu-Ching Chuang | Selvaraj Nagarajan | Chean‐Cheng Su | Li‐Ting Lee | Eamor M. Woo
Source: CrystEngComm (article, 2024-01-01)
Field: Materials Science — Biomaterials

Universality in interior periodic assembly of banded <scp>d</scp>-(−)-poly(3-hydroxybutyrate) justified with the iridescence test Periodic assembly in poly(3-hydroxybutyrate) crystallized at selected T c is analyzed with microscopy 3D interior dissection. Orderly grating-arrayed lamellae in PHB display light-interfering iridescence, resembling nature's structured coloration seen in inorganic minerals or organic species. Iridescence ; Crystallography ; Universality (dynamical systems) ; Materials science ; Chemistry ; Biophysics ; Optics ; Physics ; Biology ; Condensed matter physics biodegradable polymer synthesis and properties ; Advanced Materials and Mechanics ; Supramolecular Self-Assembly in Materials
Authors: Florence Volatron | Guillaume Izzet | D. Vuillaume | Anna Proust
Source: Comptes Rendus Chimie (article, 2024-11-07)
Field: Materials Science — Materials Chemistry

Unveiling polyoxometalate redox properties at the nanoscale Polyoxometalates (POMs) are molecular nano-oxides of early transition metals. As molecular oxides, they are endowed with remarkable redox properties, combining the reducibility of bulk metal oxides and the high versatility of molecular species. They undergo successive, reversible, and highly adjustable mono- (or multi-) electronic reduction processes within a narrow range of potentials. Furthermore, POMs are polyanions, with counter cations playing a crucial role, beyond ensuring charge neutrality. As the missing link between extended oxides, commonly found in microelectronics, and conventional organic or organometallic molecules, POMs have attracted ever-increasing interest in the field of nanoelectronics. They hold promise as charge storage nodes in multilevel nonvolatile memories and resistive switching devices, areas of interest currently boosted by the development of neuromorphic computing. In this context, we have been exploring various strategies to immobilize POMs onto electrodes with the aim of improving the control of the molecules/electrode interface. We have been investigating electron transport properties across POM-based molecular nanojunctions to establish relationships among the POM molecular structure, the electronic structure, and the properties of POM devices (e.g., conductance, switching). Additionally, we have demonstrated that we can commute the redox state of a POM layer by exposure to light or by applying an electric field, opening up new opportunities to stimuli-responsive devices. Polyoxometalate ; Redox ; Nanoscopic scale ; Nanotechnology ; Chemistry ; Materials science ; Inorganic chemistry ; Catalysis ; Organic chemistry Polyoxometalates: Synthesis and Applications ; Advanced Nanomaterials in Catalysis ; Metal-Organic Frameworks: Synthesis and Applications