scholarly journals Using the Isalos platform to develop a (Q)SAR model that predicts metal oxide toxicity utilizing facet-based electronic, image analysis-based, and periodic table derived properties as descriptors

2021 ◽  
Author(s):  
M. M. Thwala ◽  
A. Afantitis ◽  
A. G. Papadiamantis ◽  
A. Tsoumanis ◽  
G. Melagraki ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Density Functional ◽  
Chemical Potential ◽  
Metal Oxide Nanoparticles ◽  
Experimental Studies ◽  
Density Functional Theory Calculations ◽  
Quantitative Structure Activity Relationship ◽  
Engineered Nanoparticles ◽  
Metal Oxide Nanoparticle

AbstractEngineered nanoparticles (NPs) are being studied for their potential to harm humans and the environment. Biological activity, toxicity, physicochemical properties, fate, and transport of NPs must all be evaluated and/or predicted. In this work, we explored the influence of metal oxide nanoparticle facets on their toxicity towards bronchial epithelial (BEAS-2B), Murine myeloid (RAW 264.7), and E. coli cell lines. To estimate the toxicity of metal oxide nanoparticles grown to a low facet index, a quantitative structure–activity relationship ((Q)SAR) approach was used. The novel model employs theoretical (density functional theory calculations) and experimental studies (transmission electron microscopy images from which several particle descriptors are extracted and toxicity data extracted from the literature) to investigate the properties of faceted metal oxides, which are then utilized to construct a toxicity model. The classification mode of the k-nearest neighbour algorithm (EnaloskNN, Enalos Chem/Nanoinformatics) was used to create the presented model for metal oxide cytotoxicity. Four descriptors were identified as significant: core size, chemical potential, enthalpy of formation, and electronegativity count of metal oxides. The relationship between these descriptors and metal oxide facets is discussed to provide insights into the relative toxicities of the nanoparticle. The model and the underpinning dataset are freely available on the NanoSolveIT project cloud platform and the NanoPharos database, respectively.

scholarly journals N-Dopant-Mediated Growth of Metal Oxide Nanoparticles on Carbon Nanotubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1882
Author(s):  
Jin Ah Lee ◽  
Won Jun Lee ◽  
Joonwon Lim ◽  
Sang Ouk Kim
Keyword(s):  
Carbon Nanotubes ◽  
Metal Oxide ◽  
Carbon Nanomaterials ◽  
Wide Spectrum ◽  
Metal Oxide Nanoparticles ◽  
Nucleation And Growth ◽  
Oxide Nanoparticles ◽  
Metal Oxide Nanoparticle ◽  
Nucleation Sites ◽  
Direct Growth

Metal oxide nanoparticles supported on heteroatom-doped graphitic surfaces have been pursued for several decades for a wide spectrum of applications. Despite extensive research on functional metal oxide nanoparticle/doped carbon nanomaterial hybrids, the role of the heteroatom dopant in the hybridization process of doped carbon nanomaterials has been overlooked. Here, the direct growth of MnOx and RuOx nanoparticles in nitrogen (N)-doped sites of carbon nanotubes (NCNTs) is presented. The quaternary nitrogen (NQ) sites of CNTs actively participate in the nucleation and growth of the metal nanoparticles. The evenly distributed NQ nucleation sites mediate the generation of uniformly dispersed <10 nm diameter MnOx and RuOx nanoparticles, directly decorated on NCNT surfaces. The electrochemical performance of the resultant hybridized materials was evaluated using cyclic voltammetry. This novel hybridization method using the dopant-mediated nucleation and growth of metal oxides suggests ways that heteroatom dopants can be utilized to optimize the structure, interface and corresponding properties of graphitic carbon-based hybrid materials.

Blue and black phosphorene on metal substrates: a density functional theory study

2021 ◽  
Author(s):  
Abhishek Kumar Adak ◽  
Devina Sharma ◽  
Shobhana Narasimhan
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Potential ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Atomic Size ◽  
Metal Substrates ◽  
Synthesis Conditions ◽  
Black Phosphorene ◽  
Blue Phosphorene

Abstract We have performed density functional theory calculations to study blue phosphorene and black phosphorene on metal substrates. The substrates considered are the (111) and (110) surfaces of Al, Cu, Ag, Ir, Pd, Pt and Au and the (0001) and (10$\bar{1}$0) surfaces of Zr and Sc. The formation energy $E_{\rm F}$ is negative (energetically favorable) for all 36 combinations of overlayer and substrate. By comparing values of $\Delta{\Omega}$, the change in free energy per unit area, as well as the overlayer-substrate binding energy $E_{\rm b}$, we identify that Ag(111), Al(110), Cu(111), Cu(110) and possibly Au(110) may be especially suitable substrates for the synthesis and subsequent exfoliation of blue phosphorene, and the Ag(110) and Al(111) substrates for the synthesis of black phosphorene. However, these conclusions are drawn assuming the source of P atoms is bulk phosphorus, and can alter upon changing synthesis conditions (chemical potential of phosphorus). Thus, when the source of phosphorus atoms is P$_4$, blue phosphorene is favored only over Pt(111). We find that for all combinations of overlayer and substrate, the charge transfer per bond can be captured by the universal descriptor $\mathcal{D} = \Delta \chi/\Delta \mathcal{R}$, where $\Delta \chi$ and $\Delta \mathcal{R}$ are, respectively, the differences in electronegativity and atomic size between phosphorus and the substrate metal.

scholarly journals Influence of Varying Functionalization on the Peroxidase Activity of Nickel(II)–Pyridine Macrocycle Catalysts: Mechanistic Insights from Density Functional Theory

Computation ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 52
Author(s):  
Jerwin Jay E. Taping ◽  
Junie B. Billones ◽  
Voltaire G. Organo
Keyword(s):  
Density Functional Theory ◽  
Proton Transfer ◽  
Density Functional ◽  
Experimental Studies ◽  
Density Functional Theory Calculations ◽  
Catalytic Performance ◽  
Stoichiometric Ratio ◽  
Functional Theory ◽  
Pendant Arm ◽  
Spin Singlet

Nickel(II) complexes of mono-functionalized pyridine-tetraazamacrocycles (PyMACs) are a new class of catalysts that possess promising activity similar to biological peroxidases. Experimental studies with ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), substrate) and H2O2 (oxidant) proposed that hydrogen-bonding and proton-transfer reactions facilitated by their pendant arm were responsible for their catalytic activity. In this work, density functional theory calculations were performed to unravel the influence of pendant arm functionalization on the catalytic performance of Ni(II)–PyMACs. Generated frontier orbitals suggested that Ni(II)–PyMACs activate H2O2 by satisfying two requirements: (1) the deprotonation of H2O2 to form the highly nucleophilic HOO−, and (2) the generation of low-spin, singlet state Ni(II)–PyMACs to allow the binding of HOO−. COSMO solvation-based energies revealed that the O–O Ni(II)–hydroperoxo bond, regardless of pendant arm type, ruptures favorably via heterolysis to produce high-spin (S = 1) [(L)Ni3+–O·]2+ and HO−. Aqueous solvation was found crucial in the stabilization of charged species, thereby favoring the heterolytic process over homolytic. The redox reaction of [(L)Ni3+–O·]2+ with ABTS obeyed a 1:2 stoichiometric ratio, followed by proton transfer to produce the final intermediate. The regeneration of Ni(II)–PyMACs at the final step involved the liberation of HO−, which was highly favorable when protons were readily available or when the pKa of the pendant arm was low.

scholarly journals Photoinduced electron transfer from semiconductor quantum dots to metal oxide nanoparticles

2010 ◽  
Vol 108 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Kevin Tvrdy ◽  
Pavel A. Frantsuzov ◽  
Prashant V. Kamat
Keyword(s):  
Electron Transfer ◽  
Quantum Dot ◽  
Metal Oxide ◽  
Transfer Rate ◽  
Metal Oxide Nanoparticles ◽  
Strong Dependence ◽  
Hot Electron ◽  
Electron Transfer Rate ◽  
Metal Oxide Nanoparticle ◽  
Oxide Nanoparticle

Quantum dot-metal oxide junctions are an integral part of next-generation solar cells, light emitting diodes, and nanostructured electronic arrays. Here we present a comprehensive examination of electron transfer at these junctions, using a series of CdSe quantum dot donors (sizes 2.8, 3.3, 4.0, and 4.2 nm in diameter) and metal oxide nanoparticle acceptors (SnO2, TiO2, and ZnO). Apparent electron transfer rate constants showed strong dependence on change in system free energy, exhibiting a sharp rise at small driving forces followed by a modest rise further away from the characteristic reorganization energy. The observed trend mimics the predicted behavior of electron transfer from a single quantum state to a continuum of electron accepting states, such as those present in the conduction band of a metal oxide nanoparticle. In contrast with dye-sensitized metal oxide electron transfer studies, our systems did not exhibit unthermalized hot-electron injection due to relatively large ratios of electron cooling rate to electron transfer rate. To investigate the implications of these findings in photovoltaic cells, quantum dot-metal oxide working electrodes were constructed in an identical fashion to the films used for the electron transfer portion of the study. Interestingly, the films which exhibited the fastest electron transfer rates (SnO2) were not the same as those which showed the highest photocurrent (TiO2). These findings suggest that, in addition to electron transfer at the quantum dot-metal oxide interface, other electron transfer reactions play key roles in the determination of overall device efficiency.

scholarly journals Biocompatible Metal-Oxide Nanoparticles: Nanotechnology Improvement of Conventional Prosthetic Acrylic Resins

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Laura S. Acosta-Torres ◽  
Luz M. López-Marín ◽  
R. Elvira Núñez-Anita ◽  
Genoveva Hernández-Padrón ◽  
Victor M. Castaño
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Metal Nanoparticles ◽  
Suspension Polymerization ◽  
Metal Oxide Nanoparticles ◽  
Physicochemical Characterization ◽  
Dental Restoration ◽  
Oxide Nanoparticles ◽  
Dental Resins ◽  
Acrylic Resins

Nowadays, most products for dental restoration are produced from acrylic resins based on heat-cured Poly(Methyl MethAcrylate) (PMMA). The addition of metal nanoparticles to organic materials is known to increase the surface hydrophobicity and to reduce adherence to biomolecules. This paper describes the use of nanostructured materials, TiO2and Fe2O3, for simultaneously coloring and/or improving the antimicrobial properties of PMMA resins. Nanoparticles of metal oxides were included during suspension polymerization to produce hybrid metal oxides-alginate-containing PMMA. Metal oxide nanoparticles were characterized by dynamic light scattering, and X-ray diffraction. Physicochemical characterization of synthesized resins was assessed by a combination of spectroscopy, scanning electron microscopy, viscometry, porosity, and mechanical tests. Adherence ofCandida albicanscells and cellular compatibility assays were performed to explore biocompatibility and microbial adhesion of standard and novel materials. Our results show that introduction of biocompatible metal nanoparticles is a suitable means for the improvement of conventional acrylic dental resins.

scholarly journals Tuning the Magnetic Moment of Small Late 3d-Transition-Metal Oxide Clusters by Selectively Mixing the Transition-Metal Constituents

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1814
Author(s):  
Rodrigo H. Aguilera-del-Toro ◽  
María B. Torres ◽  
Faustino Aguilera-Granja ◽  
Andrés Vega
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Magnetic Moment ◽  
Density Functional ◽  
Magnetic Moments ◽  
Metal Oxide Nanoparticles ◽  
Transition Metal Oxide ◽  
Blocking Temperature ◽  
Oxide Nanoparticles ◽  
Oxidation Rates

Transition-metal oxide nanoparticles are relevant for many applications in different areas where their superparamagnetic behavior and low blocking temperature are required. However, they have low magnetic moments, which does not favor their being turned into active actuators. Here, we report a systematical study, within the framework of the density functional theory, of the possibility of promoting a high-spin state in small late-transition-metal oxide nanoparticles through alloying. We investigated all possible nanoalloys An−xBxOm (A, B = Fe, Co, Ni; n = 2, 3, 4; 0≤x≤n) with different oxidation rates, m, up to saturation. We found that the higher the concentration of Fe, the higher the absolute stability of the oxidized nanoalloy, while the higher the Ni content, the less prone to oxidation. We demonstrate that combining the stronger tendency of Co and Ni toward parallel couplings with the larger spin polarization of Fe is particularly beneficial for certain nanoalloys in order to achieve a high total magnetic moment, and its robustness against oxidation. In particular, at high oxidation rates we found that certain FeCo oxidized nanoalloys outperform both their pure counterparts, and that alloying even promotes the reentrance of magnetism in certain cases at a critical oxygen rate, close to saturation, at which the pure oxidized counterparts exhibit quenched magnetic moments.

scholarly journals Cobalt-Containing Nanoporous Nitrogen-Doped Carbon Nanocuboids from Zeolite Imidazole Frameworks for Supercapacitors

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1110 ◽  
Author(s):  
Yu Song ◽  
Mingyue Zhang ◽  
Tianyu Liu ◽  
Tianjiao Li ◽  
Di Guo ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Metal Oxide Nanoparticles ◽  
Negative Electrode ◽  
Cobalt Metal ◽  
Energy Storage Devices ◽  
Nitrogen Doped ◽  
Metal Metal ◽  
The Rich ◽  
Nitrogen Doped Carbon

Pyrolyzing metal–organic frameworks (MOFs) typically yield composites consisting of metal/metal oxide nanoparticles finely dispersed on carbon matrices. The blend of pseudocapacitive metal oxides and conductive metals, as well as highly porous carbon networks, offer unique opportunities to obtain supercapacitor electrodes with mutually high capacitances and excellent rate capabilities. Herein, we demonstrate nitrogen-doped carbon nanocuboid arrays grown on carbon fibers and incorporating cobalt metal and cobalt metal oxides. This composite was synthesized via pyrolysis of a chemical bath deposited MOF, cobalt-containing zeolite imidazole framework (Co–ZIF). The active materials for charge storage are the cobalt oxide and nitrogen-doped carbon. Additionally, the Co metal and the nanoporous carbon network facilitated electron transport and the rich nanopores in each nanocuboid shortened ion diffusion distance. Benefited from these merits, our Co–ZIF-derived electrode delivered an areal capacitance of 1177 mF cm−2 and excellent cycling stability of ~94% capacitance retained after 20,000 continuous charge–discharge cycles. An asymmetric supercapacitor prototype having the Co–ZIF-derived hybrid material (positive electrode) and activated carbon (negative electrode) achieved a maximal volumetric energy density of 1.32 mWh cm−3 and the highest volumetric power density of 376 mW cm−3. This work highlights the promise of metal–metal oxide–carbon nanostructured composites as electrodes in electrochemical energy storage devices.

scholarly journals Theoretical and Experimental Studies of the Structural, Phase Stability and Elastic Properties of AlCrTiFeNi Multi-Principle Element Alloy

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4353
Author(s):  
Li Liu ◽  
Ramesh Paudel ◽  
Yong Liu ◽  
Xiao-Liang Zhao ◽  
Jing-Chuan Zhu
Keyword(s):  
Structural Stability ◽  
Deformation Behavior ◽  
Density Functional ◽  
Low Cost ◽  
Structural Phase ◽  
Experimental Studies ◽  
Density Functional Theory Calculations ◽  
Mixing Enthalpy ◽  
Size Difference ◽  
Valence Electron Concentration

The fundamental challenge for creating the crystal structure model used in a multi-principle element design is the ideal combination of atom components, structural stability, and deformation behavior. However, most of the multi-principle element alloys contain expensive metallic and rare earth elements, which could limit their applicability. Here, a novel design of low-cost AlCrTiFeNi multi-principle element alloy is presented to study the relationship of structure, deformation behavior, and micro-mechanism. This structured prediction of single-phase AlCrTiFeNi by the atomic-size difference, mixing enthalpy ΔHmix and valence electron concentration (VEC), indicate that we can choose the bcc-structured solid solution to design the AlCrTiFeNi multi-principle element alloy. Structural stability prediction by density functional theory calculations (DFT) of single phases has verified that the most advantageous atom occupancy position is (FeCrNi)(AlFeTi). The experimental results showed that the structure of AlCrTiFeNi multi-principle element alloy is bcc1 + bcc2 + L12 phases, which we propose as the fundamental reason for the high strength. Our findings provide a new route by which to design and obtain multi-principle element alloys with targeted properties based on the theoretical predictions, first-principles calculations, and experimental verification.

Thermal Properties of Composites Containing Metal Oxide Nanoparticles

2011 ◽  
Vol 694 ◽  
pp. 146-149
Author(s):  
Ji Fen Wang ◽  
Hua Qing Xie ◽  
Zhong Xin ◽  
Yang Li ◽  
Jing Li
Keyword(s):  
Thermal Conductivity ◽  
Metal Oxide ◽  
Phase Change ◽  
Metal Oxide Nanoparticles ◽  
Hot Wire ◽  
Metal Oxide Nanoparticle ◽  
Oxide Nanoparticle ◽  
Latent Heat Capacity ◽  
Transient Short Hot Wire ◽  
Properties Of Composites

We prepared a series of paraffin wax (PW) based phase change composite containing ZnO, Al2O3 and Fe2O3 nanoparticles, respectively. DSC results showed that there is a decrease trend in phase change latent heat capacity (Ls) with an increase of metal oxide nanoparticle loadings. ZnO/PW has higher Ls than those of Fe2O3/PW and Al2O3/PW with same metal oxide nanoparticle loadings. Transient short-hot-wire (SHW) method was used to measure thermal conductivity of these composites. The results showed that nanoparticle addition leads to substantial enhancement in the thermal conductivity of the composites. The highest thermal conductivity of the measured composites is about 0.27 W/(m•K) of Fe2O3/PW with 3.0 wt% nanoparticles and Al2O3/PW with 5.0 wt% nanoparticles at 15 oC, which higher than that of PW by about 30%. The lowest thermal conductivity of composites is that of Al2O3/PW and ZnO/PW with 1.0 wt% nanoparticles at 60 oC, which higher than that of PW by about 7%.

Sign in / Sign up

Export Citation Format

Share Document