Mesoporous nanocrystalline zirconium oxide: novel preparation and photoluminescence property

A novel strategy involving the combination of soft-templating and solid–liquid method (CSSL) is presented to synthesize mesoporous nanocrystalline zirconia with high specific surface area, that is, the mesostructured zirconia hybrid is firstly synthesized via cooperative assembly between zirconium sulphate as inorganic precursor and 1-hexadecyl-3-methylimidazolium bromide (C₁₆mim⁺Br⁻) as the structure-directing agent, and subsequently ground with solid magnesium nitrate salt followed by heat-treatment in air. The resulting zirconia material after calcination at 600 °C possesses a wormlike arrangement of mesopores surrounded by tetragonal ZrO₂ nanocrystallites of ca. 2.3 nm. The BET surface area is 255 m²/g and the pore size is ca. 4.3 nm. However, no mesoporous structure exists in the obtained zirconia material via the simple soft-templating method at the same calcination temperature. Photoluminescence (PL) spectra of the obtained mesoporous nanocrystalline ZrO₂ show a strong emission peak at ca. 394 nm under UV excitation of 250 nm wavelength.