Enhancement of CeO₂ Silanization by Spontaneous Breakage of Si–O Bonds through Facet Engineering

Abstract

Facet engineering is a new method of materials design with considerable potential for many technological applications. The present work uses DFT calculations to understand how this strategy can be used to accelerate the silanization of tetraethyl orthosilicate (TEOS) on the surface of ceria (CeO2), which is a key technology in biomedical and other fields. Cubic CeO2 nanoparticles with exposed {100} facets are shown to represent the most favorable morphology for silanization owing to (1) the facilitated adsorption of TEOS on these facets compared to the {110} and {111} facets and (2) spontaneous breakage of the Si–O bonds of TEOS, which is found to be the rate-determining step for silanization of CeO2. The favorable adsorption on the {100} facets arises from its superior structural and electronic properties as well as higher reactivity, which are attributed to its more open arrangement of the surface atoms and consequently reduced steric hindrance, higher density of dangling bonds and surface active sites, and the larger difference in Mulliken charges between the surface and bulk atoms.

Changes in Mechanical Properties of Polyhydroxyalkanoate with Double Silanized Cellulose Nanocrystals Using Different Organosiloxanes

“…Silanization is an effective grafting method for obtaining hydrophobically modified nanocellulose, by substituting OH groups on the surface with various Si-containing end groups [14,23,24,30]. Many studies used tetraethyl orthosilicate (TEOS) and methyltrimethoxysilane (MTMS) as organic precursors of alkoxysilane for the surface modification of CNCs, due to their low cost, low toxicity, and chemical stability [31,32]. It was reported that silanized cellulose nanofibers showed good adhesion with PHA based composites and contributed to the enhancement of their mechanical properties [23,33].…”

Carboxylic acid ligand substituent impacts hydrosilylation activity of platinum single atom catalysts on ceria

“…Based on the Ce 3d attenuation of 19%, we estimate the silane coverage to have a thickness of approximately 1.5-2.2 nm (eqn (S1) †). [47][48][49] The O 1s peak at 528.9 eV, corresponding to lattice oxygen, 50 has reduced intensity after exposure to HSi(OMe) 2 Me, again consistent with overlayer coverage (Fig. 8b).…”

Two decades of ceria nanoparticle research: structure, properties and emerging applications

“…54–58 Facet engineering can be used as a powerful tool to enhance the modification of CeNPs, for example, silanization through the favorable adsorption of tetraethyl orthosilicate (TEOS) on the (100) facets and spontaneous breakage of the Si–O bonds of TEOS as the rate determining step for silanization. 59…”