Effect of silica surface area on molecular structures of lead in thermally treated mixtures of lead acetate and silica oxide

Yu Ling Wei, Kai Wen Cheng, Nicky Cheng, H. Paul Wang

研究成果: Conference contribution

摘要

The extent of lead dispersion can affect lead molecular environment in lead silicate. Mixtures of lead acetate and silica oxide were heated at 500 and 1100 °C for two hours. Two silica oxides (a quartz, syn and an amorphous SiO2) of different surface areas were used in this study. The final products were investigated with X-ray absorption spectroscopy, X-ray diffraction, BET surface meter, and scanning electron microscopy. The XRD results observe the existence of PbSiO3, Pb(0), and PbO (litharge, syn) only in the mixture of lead acetate and quartz heated at 1100 °C, as well as SiO2 (cristobalite, syn). The mixture of lead acetate and the amorphous SiO2 heated at 1100 °C basically remains as amorphous although its XRD patterns do show some low-intensity peaks of SiO2 (cristobalite, syn). Both BET and SEM results indicate that sintering occurs at 1100 °C. Results from the fitting of Fourier transformed Pb L III-edge EXAFS spectra from the heated mixtures shows that both first-shell (Pb-O) interatomic distance and coordination number depend on the type of starting materials and the thermal treatment temperature. Pb first-shell coordination number decreases with increasing temperature for both low-surface area and high-surface area mixtures. The high-surface area mixture after heating at 500 °C have greater first-shell coordination number than the corresponding low-surface area sample. However, after thermal treatment at 1100 °C, both mixtures have similar first-shell coordination number. The interatomic distance for the first shell for all thermally treated mixtures is 2.18-2.28 Å. The high-surface area mixture treated at 1100 °C has the shortest first-shell interatomic distance (2.18 Å).

原文English
主出版物標題X-RAY ABSORPTION FINE STRUCTURE - XAFS13
主出版物子標題13th International Conference
頁面657-659
頁數3
DOIs
出版狀態Published - 2007
事件X-RAY ABSORPTION FINE STRUCTURE - XAFS13: 13th International Conference - Stanford, CA, United States
持續時間: 2006 7月 92006 7月 14

出版系列

名字AIP Conference Proceedings
882
ISSN(列印)0094-243X
ISSN(電子)1551-7616

Other

OtherX-RAY ABSORPTION FINE STRUCTURE - XAFS13: 13th International Conference
國家/地區United States
城市Stanford, CA
期間06-07-0906-07-14

All Science Journal Classification (ASJC) codes

  • 物理與天文學 (全部)

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