Oxygen Adsorption Properties of Microporous Silica Derived from Layered Siloxene by Oxidation
Layer structured siloxene prepared by the reaction of CaSi2 with hydrochloric acid was further oxidized by a treatment with water. During this treatment, the Si-Si and the Si-H bonds of the siloxene were oxidized to Si-O-Si and Si-OH bonds, respectively, and the interlayers were cross-linked by the condensation of the Si-OH groups. The resulting compounds have high surface areas (400–600 m2/g) with pores in the micropore to mesopore ranges. The compounds calcined in a vacuum up to 1000°C keep the high surface area and show peculiar electron spin resonance (ESR) centers on adsorption of oxygen, which are attributed to the formation of silicon dangling bonds. The ESR centers disappear reversibly on desorption of oxygen.
KeywordsElectron Spin Resonance Electron Spin Resonance Spectrum Electron Spin Resonance Signal Dangling Bond Microporous Material
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