X-ray investigations into silica/silver nanocomposite

Abstract

X-ray diffraction data revealed that the initial SiO2/Ag nanocomposite, manufactured in a chemical synthesis process, is mainly composed of silica in amorphous phase (95.5 wt.%), crystalline Ag with a cubic structure (Fm-3m) and cristobalite (SiO2) with a tetragonal structure (P41212) in the amount of 4.2 and 0.3 wt.%, respectively. High-temperature diffraction data revealed high stability of the SiO2/Ag composite up to 1000 °C. High-temperature X-ray diffraction measurements revealed phase cristallization temperatures of silica at 1060 °C for cristobalite and 1080 °C for tridymite as well as temperature of silver evaporation starting from the composite (ca. 1000 °C). Infrared spectroscopy data confirmed the presence of amorphous matrix with embedded silver ions and crystalline compounds in the form of cristobalite and tridymite without silver after thermal treatment.