Pd/SiO₂ Organic-Inorganic Hybrid Materials by Sol-Gel Method: Preparation and Thermal Stability under H₂ Atmosphere

Abstract:

Pd/SiO₂ organic-inorganic hybrid materials were prepared by adding PdCl₂ into methyl-modified silica sol. The Pd/SiO₂ hybrid materials were characterized by X-ray diffraction (XRD), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of calcination temperature and Pd-doping on the phase transition of Pd element and the thermal stability of CH₃ group in the Pd/SiO₂ organic-inorganic hybrid materials were investigated. The results showed that the reduced metallic Pd⁰ exhibits good thermal stability under H₂ atmosphere in the calcination process. Pd element in noncalcined Pd/SiO₂ materials exists in PdCl₂ form, calcination at 200 °C in a H₂ atmosphere produces some metallic Pd⁰ and calcinations at 350 °C results in the complete transformation of Pd²⁺ to metallic Pd⁰. With the increase of calcination temperature, the Pd⁰ particle sizes increase and the hydrophobic Si−CH₃ bands decrease in intensity. As the calcination temperature is greater than or equal to 350 °C, the loading of metallic Pd⁰ nearly has no influence on the chemical structure but, with the increase of Pd content, the formed Pd⁰ particle size increases. To keep the hydrophobicity of Pd/SiO₂ membrane materials, the optimal calcination temperature is about 350 °C under H₂ atmosphere.

• Periodical: Advanced Materials Research (Volume 1118)
• Pages: 20-27
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1118.20
• Online since: July 2015
• Authors: Jing Yang*, Bao Song Li, Xiang Huo, Hao Xu, Hai Yun Hou
• Keywords: H₂ Atmosphere, Palladium Doping, Sol-Gel Method, Thermal Stability

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