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| Hydrophobicity and Phase Changes of Pd/SiO2 Organic-inorganic Hybrid Materials Calcined in Air Atmosphere |
| Jing Yang, Baosong Li, Hao Xu, Yue Li, Xiang Huo |
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Abstract Pd/SiO2 organic-inorganic hybrid material was prepared by sol-gel method, in which PdCl2 was added into methyl-modified silica sol. The Pd/SiO2 sol particle size distribution, the hydrophobicity and phase changes of Pd/SiO2 hybrid materials calcined at 200, 350, 500, 600 and 750 ℃ in air atmosphere were discussed. The Pd/SiO2 sol system exhibits moderate dispersion and the mean particle size of Pd/SiO2 sol is 2.70 nm. When the calcination temperature is raised to 350 ℃, metallic palladium of high crystallinity is formed in the Pd/SiO2 sample. PdO occurs in minor quantities in the Pd/SiO2
sample calcined at 500 ℃, which increases in amount in the samples calcined at 600 and 750 ℃. With the increase of calcination temperature, the Si-CH3 and Si-OH bands in Pd/SiO2 materials are found to decrease in absorption intensity and the hydrophobicity on Pd/SiO2 film surfaces increases. The water contact angle on the Pd/SiO2 film surface achieves the maximum value as the calcination temperature is up to 350 ℃ and the particle sizes of the formed metallic Pd are about 15?20 nm. The optimal calcination temperature for hydrophobic Pd/SiO2 membrane materials is about 350 ℃.
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Jing Yang,Baosong Li,Hao Xu, et al. Hydrophobicity and Phase Changes of Pd/SiO2 Organic-inorganic Hybrid Materials Calcined in Air Atmosphere[J]. Journal of Fiber Bioengineering and Informatics, 2014, 7(1): 117-127.
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2014, Vol. 7 
