In this paper, temperature dependence of nanoporous framework evolution process and variety of pore properties (pore volume, specific surface area (BET), and pore size) of SiO 2 aerogels were characterized by FTIR, XPS, XRD, SEM, TEM, BET, BJH, etc. Results show that SiO 2 aerogels treated at different temperatures all possess amorphous structure. With the increase of treated temperatures, BET values of SiO 2 aerogels increase initially and then decrease, and it reaches the maximum value of 882.81 m 2 /g when treated at 600 ℃ for 2 h due to the addition of the nanopores and shrinkage skeleton of SiO 2 aerogels. Higher temperatures may result in a framework transformation and particle growth; both factors could reduce the BET values of the aerogels. Nanoporous skeleton of SiO 2 aerogels at room temperatures is composed of tetrahedron with a pore size of about 22.28 nm. Higher treated temperatures result in an increase of octahedron amount in nanoporous framework and a decrease of pore size. When treated at 1000 ℃, an approximate dense SiO 2 bulk via the framework collapse and particle growth is obtained. These varieties are derived from the formed extra bonds of Si-O-Si, higher local stress, and liquid phase between particles during heat treatment process.

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