文献类型：期刊文献

英文题名：Effect of Zr on the Microstructure and High-Temperature Phase Separation Evolution of SiOC Aerogels

作者：Han, Yuqing[1];Wu, Youqing[1];Huang, Sheng[1,2];Zhang, Hong[3];Liang, Zijun[1];Guan, Xuebo[3];Wu, Shiyong[1,2]

机构：[1]East China Univ Sci & Technol, Dept Chem Engn Energy Resources, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Engn Res Ctr Resource Utilizat Carbon containing W, Minist Educ, Shanghai 200237, Peoples R China;[3]Naicher New Mat Yingkou Co Ltd, Yingkou 115004, Peoples R China

年份：2023

卷号：39

期号：45

起止页码：15950

外文期刊名：LANGMUIR

收录：;EI(收录号：20234815137846);WOS:【SCI-EXPANDED(收录号:WOS:001096867100001)】；

基金：This work was supported by the Key Technologies Program of the Yingkou Science and Technology Bureau [Item No. 2022JH3/0200003].

语种：英文

外文关键词：Aerogels - Amorphous silicon - Carbon - Phase separation - Pore structure - Pyrolysis - Silicon carbide - Thermal conductivity - Zirconia - Zirconium

摘要：SiZrOC aerogels were synthesized through the pyrolysis of the zirconium source-doped SiOC system using zirconyl chloride octahydrate (ZrOCl28H(2)O) at temperatures ranging from 900 to 1300 degrees C. This study investigates the microstructure evolution and phase separation of SiOC and SiZrOC aerogels during the pyrolysis process. Upon pyrolysis, both aerogels exhibited a Si-O-C structure with a high thermal stability. The introduction of zirconium elements significantly enhanced the pore volume (3.20 cm(3)/g) and porosity (96.0%) and reduced the thermal conductivity (0.023 Wm(-1)K-1) of the organic-inorganic precursor aerogel. Moreover, the three-dimensional pore structure was retained even under high-temperature pyrolysis conditions. SiZrOC-1100 displayed a high specific surface area of 273.52 m(2)/g, a high pore volume of 1.70 cm(3)/g, and a low thermal conductivity of 0.033 Wm(-1)K-1. At high temperatures, the SiZrOC phase transformation produces tetragonal ZrO2, which inhibits the graphitization process of free carbon and the growth of SiC grains. Furthermore, the phase separation process of the SiOxCy matrix structure generated oxygen-rich SiOxC4-x units, while carbon-rich SiOxC4-x units were negligible below a pyrolysis temperature of 1200 degrees C. Between 900 and 1200 degrees C, SiZrOC is composed of amorphous SiOC, amorphous ZrO2, microcrystalline t-ZrO2, and free carbon phase. These findings provide valuable insights into the preparation of high-performance SiOC aerogels.