Realistic Models of Hydroxylated Amorphous Silica Surfaces and MCM‐41 Mesoporous Material Simulated by Large‐scale Periodic B3LYP Calculations

Abstract

Realistic models of amorphous silica surfaces with different degrees of hydroxylation and of the MCM‐41 mesoporous material are determined ab initio at the B3LYP level. Comparison with structural and vibrational experimental data confirms the validity of these models, which will be very useful for future computational studies.

Effect of Silica Surface Properties on the Formation of Multilayer or Submonolayer Protein Hard Corona: Albumin Adsorption on Pyrolytic and Colloidal SiO2 Nanoparticles

“…Of course, such a value cannot be related only to silanols exposed on the surface of M−SiO 2 NPs measured by N 2 adsorption because the maximum amount of OH groups that can be present on the silica surface is 7 OH per nm 2 . 41 Also, the density of silanols at the surface of P−SiO 2 was overestimated because of the presence of intraglobular ≡Si−OH (vide infra). To distinguish between surface and sub-surface silanols, SiO 2…”

Silica Surface Features and Their Role in the Adsorption of Biomolecules: Computational Modeling and Experiments

“…510 Data of Table 5 The values also confirm that the endothermicity dramatically increases with the degree of dehydroxylation up to 359 kJ/mol to reach the 1.5 OH/nm 2 case. The infrared spectrum in the OH region for a hypothetical surface exhibiting 4.5 OH/nm 2 is given in Figure 36 (see original work 509 for technical details). In order to account for the non-uniform OH density of a real silica surface, the spectral contributions from each of the considered models have been merged, with weights reflecting the expected experimental populations, obtaining a very good agreement with the experimental spectrum recorded for an Aerosil 300 from Degussa outgassed at 450 K in the OH stretching region (see Figure 36).…”

“…surfaces only exhibiting Si-O-Si bridges and Si-OH groups, the main functionalities present in water environment. We have singled out two models obtained using quantum mechanical methods based on DFT: the first one from Tielens et al 510 and the second one from Ugliengo et al, 509 respectively.…”

Experimental and first-principles IR characterization of quercetin adsorbed on a silica surface

“…The silica model adopted rests on a careful previous study [14] involving dynamic simulations to reproduce the bulk and surface features of an amorphous, neutral silica.…”

“…The surface is represented by a realistic model of hydroxylated amorphous silica layers as designed by Ugliengo et al [14] exhibiting a surface OH density of 4.5 nm −2 , a thickness of 7.2 Å and a surface area per unit cell of 161.8 Å 2 [15]. All the calculations reported in the manuscript are performed with the public version of the program Crystal [12,16] for ab initio quantum chemistry of solid state.…”