Cleavage of functionalized organic group and role of active sites for very low concentration of gaseous wet methyl iodide in the presence of Ag nanoparticles in organofunctional silica-gel network

摘要

Electron-beam (e-beam) irradiation (270 kGy), applied to Ag nanoparticle (Ag NP) production, causes a chain cleavage of propylethylenediamine in a Ag NP-embedded propylethylenediamine-anchored SiO2 gel (Ag NP-PEDA gel) network, releasing some volatile organic compounds (VOCs) by thermalizing the gel at 150 degrees C. The introduced gaseous wet CH3I can become entrapped in interstitial positions and can surround the Ag NPs, the remaining organics, or the Ag NP-amine in a silica-gel network, and another CH3I was found to form a methoxy species, Si-OCH3, on the silica surface with the iodine leaving group (I-) not being chemically detected. The interactions between Ag NPs and N donor (of amine) and between amine and the methyl group (of CH3I) were confirmed respectively. Ag NPs do not seem to directly produce AgI with CH3I under our experimental conditions. Significantly enhanced Raman signals, strong emissions, interesting but different results between Fourier transform infrared (FT-IR) and attenuated total reflectance (ATR) spectroscopy data, and newly released VOCs were all described to support the interaction properties between the very low concentration of gaseous wet CH3I and the prepared Ag NP-PEDA gel under the controlled experimental conditions. (C) 2018 Elsevier B.V. All rights reserved.