Theoretical Approach to Rough Surface Characterization for Silica Materials

Aslyamov, Timur; Khlyupin, Aleksey; Pletneva, Vera; Akhatov, Iskander

doi:10.1021/acs.jpcc.9b07761

Cited by 18 publications

(15 citation statements)

References 38 publications

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“…With increasing synthesis temperature, the SSA significantly decreases. This behavior and the numerical SSA values are consistent with similar measurements for popular silica materials such as CPG and LiChrospher 33 . (For more information, see the Supplementary Information).…”

Section: Resultssupporting

confidence: 88%

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Environmentally Friendly Method of Silicon Recycling: Synthesis of Silica Nanoparticles in an Aqueous Solution

Bondareva

Aslyamov

Kvashnin

et al. 2020

ACS Sustainable Chem. Eng.

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Future decades will experience tons of silicon waste from various sources, with no reliable recycling route. The transformation of bulk silicon into SiO2 nanoparticles is environmentally 2 significant because it provides a way to recycle residual silicon waste. To address the needs of silicon recycling, we develop a top-down approach that achieves 100% conversion of bulk silicon to silica nanoparticles with outcome sizes of 8-50 nm. In addition to upcycling the potential of silica, our method also possesses several advantages, such as simplicity, scalability and controllable particle size distribution. Many fields of science and manufacturing, such as optics, photonics, medical, and mechanical applications, require size-controllable fabrication of silica nanoparticles. We demonstrate that control over temperature and hydrolysis time has a significant impact on the average particle size and distribution shape. Additionally, we unravel the process of nanoparticle formation using a theoretical nucleation model and quantum density functional theory calculations. Our results provide a theoretical and experimental basis for silica nanoparticle fabrication and pave the way for further silicon conservation research.

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Section: Resultssupporting

confidence: 88%

“…This behavior and the numerical SSA values are consistent with similar measurements for popular silica materials such as CPG and LiChrospher. 34 (For more information, see the Supporting Information.) ■ DISCUSSION DFT Calculations.…”

Section: ■ Resultsmentioning

confidence: 99%

Environmentally Friendly Method of Silicon Recycling: Synthesis of Silica Nanoparticles in an Aqueous Solution

Bondareva

Aslyamov

Kvashnin

et al. 2020

ACS Sustainable Chem. Eng.

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“…That is also expected to be mainly the case in the SBA-15 silica here, consistent with the elemental analysis discussed in paper P1. In the more restricted environment of these silica mesopores, surface roughness , on the walls may also be playing some role, serving as trapping sites for either the AuNPs or added Bz. Even so, we would not expect any appreciable differences in hfcc for MuĊ 6 H 6 , in accord with the two distinct ALC resonances consistently seen (Figures –).…”

Section: Alc Experimental Resultsmentioning

confidence: 99%

Level Crossing Resonance Studies of the Muoniated Cyclohexadienyl Radical (MuĊ₆H₆) Interacting with Uncapped Gold Nanoparticles in Porous Silica Hosts

et al. 2021

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The study of metal nanoparticles (NPs) and gold NPs (AuNPs), in particular, has been a subject of considerable interest in recent years. The present paper reports on the formation of the muoniated cyclohexadienyl radical in the Mu + C6H6 → MuĊ6H6 addition reaction in the same 8 and 10 nm AuNP samples, encapsulated in SBA-15 mesoporous silica, where the spin-relaxation rates λMu were recently reported on [ Fleming Fleming J. Phys. Chem. C201912327628, paper “P1”], but the final state was not identified in that study. The formation of this MuĊ6H6 radical and its interactions with the AuNP surfaces is investigated herein by the technique of avoided level crossing (ALC) resonance spectroscopy, for the same range of Bz loadings as studied earlier. The positions of the level crossings, giving the hyperfine coupling constants (hfcc) for the C–Mu and C–H bonds at the “ipso” position where Mu adds to the ring, are essentially the same as those seen in solid Bz and in bare silica, and hence these hfcc do not distinguish site locations for the surface-adsorbed benzene. The amplitudes of these resonances, which are a measure of the fraction of Mu forming the free-radical final state, do, however, provide such a distinction, being much less for Bz adsorbed in the AuNP/silica samples than in the bare silica. This loss in amplitude is attributed to competitive reaction channels, one forming the MuĊ6H6 free radical interacting with the AuNPs and the other due to formation of diamagnetic final states. An important signpost as to the nature of these competitive reaction channels is provided by the measured widths of the ALC resonances seen. These are surprisingly narrower in the presence of the AuNPs than for the bare silica, implying that the MuĊ6H6 radical is not in direct contact with the AuNPs. These differing possibilities and contrasting mechanisms are discussed.

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“…Studying fluids in confinement at scales from micrometers to nanometers might be important for many technological industries, such as biomolecular engineering, the fabrication of novel materials, and the oil and gas industry. − For instance, for the petroleum industry in unconventional reservoirs, most of the pore space represent structures with a width of several nanometers. ,, On such a scale, classical approaches have limitations, and it becomes necessary to take into account intermolecular forces more accurately to describe such physical phenomena as adsorption, , capillary condensation, wetting transition, , heterogeneity of the reservoir walls, − and so forth. An accurate description of these phenomena and the physical properties of materials is extremely important for industry.…”

Section: Introductionmentioning

confidence: 99%

Variation-Free Approach for Density Functional Theory: Data-Driven Stochastic Optimization

Kanygin

Nesterova

Lomovitskiy

et al. 2022

Ind. Eng. Chem. Res.

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Density functional theory (DFT) is an efficient instrument for describing a wide range of nanoscale phenomena: wetting transition, capillary condensation, adsorption, etc. In this paper, we suggest a method for obtaining the equilibrium molecular fluid density in a nanopore using DFT without calculating the freeenergy variationVariation-Free Density Functional Theory (VF-DFT). This technique can be used to explore confined fluids with a complex type of interactions, additional constraints, and, to speed up calculations, which might be crucial in an inverse problem. The fluid density in VF-DFT approach is represented as a decomposition over a limited set of basis functions. We applied principal component analysis (PCA) to extract the basic patterns from the density function and take them into account in the construction of a set of basis functions. The decomposition coefficients of the fluid density by the basis were sought by stochastic optimization algorithms: genetic algorithm (GA) and particle swarm optimization (PSO), to minimize the free energy of the system. In this work, two different fluids were studied: nitrogen at a temperature of 77.4 K and argon 87.3 K, at a pore size of 3.6 nm, and the performance of optimization algorithms was compared. We also introduce the Hybrid Density Functional Theory (H-DFT) approach based on stochastic optimization methods and the classical Picard iteration method to find the equilibrium fluid density starting from the physically appropriate solution. The combination of Picard iteration and stochastic algorithms helps to significantly speed up the calculations of equilibrium density in the system without losing the quality of the solution, especially in cases with the high relative pressure and expressed layering structure.

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Theoretical Approach to Rough Surface Characterization for Silica Materials

Cited by 18 publications

References 38 publications

Environmentally Friendly Method of Silicon Recycling: Synthesis of Silica Nanoparticles in an Aqueous Solution

Environmentally Friendly Method of Silicon Recycling: Synthesis of Silica Nanoparticles in an Aqueous Solution

Level Crossing Resonance Studies of the Muoniated Cyclohexadienyl Radical (MuĊ₆H₆) Interacting with Uncapped Gold Nanoparticles in Porous Silica Hosts

Variation-Free Approach for Density Functional Theory: Data-Driven Stochastic Optimization

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Theoretical Approach to Rough Surface Characterization for Silica Materials

Cited by 18 publications

References 38 publications

Environmentally Friendly Method of Silicon Recycling: Synthesis of Silica Nanoparticles in an Aqueous Solution

Environmentally Friendly Method of Silicon Recycling: Synthesis of Silica Nanoparticles in an Aqueous Solution

Level Crossing Resonance Studies of the Muoniated Cyclohexadienyl Radical (MuĊ6H6) Interacting with Uncapped Gold Nanoparticles in Porous Silica Hosts

Variation-Free Approach for Density Functional Theory: Data-Driven Stochastic Optimization

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Level Crossing Resonance Studies of the Muoniated Cyclohexadienyl Radical (MuĊ₆H₆) Interacting with Uncapped Gold Nanoparticles in Porous Silica Hosts