은 나노입자 혹은 은 양이온을 내포하는 메르캅토프로필 작용기화 실리카 겔과 기체 메틸아이오다이드 간의 상호작용 비교

Abstract

Mercaptopropyl-functionalized silica gels Including Ag+ ions or Ag nanoparticles were prepared and were used to investigate the mechanism followed for the adsorption of gaseous CH3I by each Ag. To determine the efficiency of the Ag nanoparticle embedment process utilized, Ag nanoparticles were embedded into the mercaptopropyl-functionalized silica gel through the wet chemistry method or through the electron beam irradiation method. The wet chemistry method facilitated the adsorption of the additives used for the synthesis of the silica gels with the Ag nanoparticles. In contrast, during the electron beam irradiation method, the ligand was cleaved by the electron beam and the cleavaged ligand particles underwent reassembly, followed by the interaction of the Ag nanoparticles with the silica gel. Therefore, the wet chemistry method was found to be unsuitable owing to the presence of residual additives. The embedment of the Ag nanoparticles in the silica gel samples was confirmed through transmission electron microscopy and a change in the color of the silica gels; this was followed by exposure to gaseous CH3I. Various spectroscopic analyses were used to investigate the chemical and physical changes associated with the interaction between the silica gels including different oxidation states of Ag and gaseous CH3I; X-ray photoelectron spectroscopy provided clear results. The Ag nanoparticles formed covalent bonds with the mercaptopropyl ligands, whereas the Ag+ ions formed ionic bonds. Physisorption occurred between the Ag+ ions and gaseous CH3I, followed by the decomposition of the gaseous CH3I by ultraviolet rays, resulting in the formation of AgI through an interaction between the Ag+ ions and I- . In contrast, the Ag - 5 - nanoparticles was maintained, which suggests that the Ag nanoparticles do not form AgI and gaseous CH3I remains on the surface of Ag nanoparticles. This study confirmed that the mechanism through which gaseous CH3I interacts with Ag depends on the oxidation state.