A series of magnetic solid acid nano-catalysts were designed and prepared through a facile co-precipitate approach. The original nanocomposites ZrO2–Al2O3–Fe3O4 were characterized by means of ICP-AES, BET, XRD, TEM, HRTEM, VSM, FT-IR, NH3-TPD and TG. Their catalytic behaviours were investigated via esterification, the synthesis of bis-indolylmethanes, Hantzsch reaction, Biginelli reaction and Pechmann reaction. In all of these organic reactions, the corresponding products were obtained in moderate to excellent yields. The optimal catalyst was ZAF-16/16, which retained catalytic activity after several recycles.

A novel fluorescent Fe3+ probe (L)based on 2-(2-hydroxyphenyl)benzothiazole has been synthesized and characterized. Both UV-vis and fluorescence spectroscopic studies demonstrated that L was highly sensitive and selective towards Fe3+ over other metal ions in acetonitrile. Upon binding with Fe3+, the emission band of L red-shifted from 370 nm to 420 nm and the fluorescence intensity was enhanced ∼103-fold. The lowest detection limit for L is 6.04 × 10−8 M and the dissociation constants Kd is 1.13 × 10−11 M, which were calculated from the fluorescence titration curves. The detailed UV-vis and fluorescent titrations studies suggested that the binding stoichiometry of the L–Fe3+ complex was 2:1, and the structure between L and the Fe3+ complex was confirmed by the 1H NMR titration. Then IR spectra provided further proof of the binding mode of the L–Fe3+ complex.

In the work, we report a facile template-free approach to prepare hollow VO2 microspheres. Uniform hollow VO2 assemblies composed of ordered microspheres with an average diameter of 3.0 µm and a hollow interior of 2.0 µm were prepared by calcining the precursor, which was synthesized via heat preservation process sealed in Teflon-lined stainless autoclave in the presence of urea. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scan electron microscopy (SEM) have been used to characterize VO2 microspheres. The proposed mechanism for the formation of hollow VO2 microspheres is discussed.

A series of magnetic solid acid nano-catalysts were designed and prepared through a facile co-precipitate approach. The original nanocomposites ZrO2–Al2O3–Fe3O4 were characterized by means of ICP-AES, BET, XRD, TEM, HRTEM, VSM, FT-IR, NH3-TPD and TG. Their catalytic behaviours were investigated via esterification, the synthesis of bis-indolylmethanes, Hantzsch reaction, Biginelli reaction and Pechmann reaction. In all of these organic reactions, the corresponding products were obtained in moderate to excellent yields. The optimal catalyst was ZAF-16/16, which retained catalytic activity after several recycles.