Mesoporous aluminum-doped titanium dioxide(Al-TiO2) materials with high specific surface areas were prepared via a solid-state reaction route.The properties of these materials were characterized by X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM),energy dispersive spectroscopy(EDS),N2 absorption-desorption,ultraviolet visible light spectroscopy(UV-Vis) and electrochemical spectroscopy.The results show that the mesoporous structure of the product with ethanol is composed of anatase laced crystal walls with amorphous grain boundaries formed gradually by degradation.Compared with those without ethanol,these samples possess larger crystallite size since ethanol decreases the pore size at higher temperature.With the increase of ethanol amount,however,the crystallite size will grow.The amorphous grain boundaries in the mesoporous material,with a large impedance and low incidental cyclic potential,are difficult to effectively degrade and the phase transformation temperature is changed from 500 to 550℃.The growth rate of Al-TiO2 crystallites that obeys the quadratic polynomial equation may be controlled.
Mesoporous chromium aluminophosphate(CrAlPO)was successfully synthesized via solid state reaction(SSR)route at low temperature in the presence of a cationic surfactant cetyltrimethyl ammonium bromide(CTAB)and inorganic sources such as AlCl_3·6H_2O,CrCl_3·6H_2O and NaH_2PO_4·2H_2O.Characterizations by means of powder X-ray diffraction(XRD),N_2 adsorption-desorption,high resolution transmission electron microscopy(HR-TEM),scanning electron micrography(SEM),energy dispersion spectroscopy(EDS),thermo-gravimetry(TG),Fourier transform infrared spectroscopy(FT-IR),and ultraviolet visible light spectroscopy(UV-Vis)were carried out to understand both the pore characteristics and electron transition route of these obtained materials.The experimental results show that the meso-CrAlPO materials with various Cr/Al molar ratios possess a mesostructure and a specific surface area of 193 to 310 m^2 /g corresponding to an average pore size of 5.5 to 2.2 nm,respectively.The maxium content of Cr in meso-CrAlPO materials synthesized via SSR route can achieve 16.7wt%,being significantly higher than that of the meso-CrAlPO prepared via a conventional sol-gel route.Meanwhile,the formation mechanism of the meso-CrAlPO was also proposed.
