Silicon-aluminum composite aerogel material with controllable structure and preparation method thereof

The invention discloses a silicon-aluminum composite aerogel material with a controllable structure and a preparation method of the silicon-aluminum composite aerogel material, and belongs to the technical field of aerogel materials. The silicon-aluminum composite aerogel material is prepared by using fly ash floating beads and silicate ester containing a Si-O structure as raw materials, ethanol as a solvent and a specific doping agent as auxiliary materials through a doped sol-gel method. The obtained silicon-aluminum composite aerogel material is good in mechanical hardness, high in porosity, low in density and large in specific surface area. Compared with a conventional method in which fly ash is independently and directly used as a raw material, the method has the advantages that the content and the utilization rate of silicon and aluminum in the raw material are greatly improved, the defect that the Al-Si ratio in the raw material cannot be effectively adjusted when fly ash is independently used as the r