Thermally stable mesoporous tetragonal zirconia through surfactant-controlled synthesis and Si-stabilization.

Thermally stable, highly mesoporous Si-stabilized ZrO 2 was prepared by sol-gel-synthesis. By utilizing the surfactant dodecylamine (DDA), large mesopores with a pore width of ∼9.4 nm are formed. Combined with an NH 3 -treatment on the hydrogel, a high specific surface area of up to 225 m 2 g -1 and pore volume up to 0.46 cm 3 g -1 are obtained after calcination at 973 K. The individual contributions of Si-addition, DDA surfactant and the NH 3 -treatment on the resulting pore system were studied by inductively coupled plasma with optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), N 2 sorption, and transmission electron microscopy (TEM). Electron tomography was applied to visualize and investigate the mesopore network in 3D space. While Si prevents the growth of ZrO 2 crystallites and stabilizes the t-ZrO 2 phase, DDA generates a homogeneous mesopore network within the zirconia. The NH 3 -treatment unblocks inaccessible pores, thereby increasing specific surface area and pore volume while retaining the pore width distribution.