Hongjun Ji

Influence of counter-ions on the self-assembly of ZrO2 nanodisks.

In three strong inorganic acidic conditions (HNO(3), HCl and H(2)SO(4)), we have prepared a series of air-water interfacial zirconium dioxide (ZrO(2)) films at normal temperature via a self-assembly technique, by using dodecylbenzenesulfonic acid (DBSA) as template and Zr(OC(4)H(9))(4) as precursor. X-ray diffraction (XRD), transmission electron microscope (TEM), UV-vis and fluorescence spectra have been used to characterize the ZrO(2) films. Results show that a number of worm-like mesoporous nanodisks and ambiguously mesoporous nanodisks are observed in the ZrO(2) films with NO(3)(-) and SO(4)(2-) counter-ions, respectively. Remarkably, a great many perfect target-like multiring nanodisks are obtained in the ZrO(2) sample with Cl(-) counter-ion. The self-assembly mechanism for ZrO(2) nanodisks has been purposely discussed. A model based on the structural changes with respect to the influence of counter-ions on the self-assembly of ZrO(2) nanodisks is therefore proposed. In addition, the structural changes for the ZrO(2) films self-assembled at a higher temperature have been discussed in combination with the influence of counter-ions.

Self-assembly of disk-like multiring ZnO–SnO2 colloidal nanoparticles

ZnO-SnO(2) colloidal nanoparticles have been successfully synthesized by using the composite of ZnCl(2) and Sn(OC(4)H(9))(4) as inorganic precursor and dodecylbenzenesulfonic acid (DBSA) as an organic template. The assembled nanostructures of ZnO-SnO(2) products have been carefully investigated by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). It is found that ZnO-SnO(2) colloidal nanoparticles take a disk-like multiring nanostructure. This interesting structure is predominantly determined by the tenacity for ZnO-SnO(2) mixtures to stabilize lamellae. A mechanism based on electrostatic interactions between the precursor and template has been proposed to illustrate the resulting nanoparticle structure.

Self-assembled SnO2 film with low density

A new kind of metallic oxide film consisted of nanodisks with porous structure has been prepared, which is different from that of targetlike multirings previously reported by our group. Herein, the SnO2 film has been prepared by using tin(IV) tert-butoxide as precursor, sodium dodecyl sulfonate (SDS) as template and gelatin as stabilizer. Results show that the SnO2 film is usually composed of series nanodisks with the diameters ranging from 0.1?m to 1?m and each disk displays worm-like porous structure in the transmission electron microscope (TEM) observation. These SnO2 nanodisks are suggested to born inside the solution and gradually rise up to the air-water interface due to low density of the disk or disk cluster. After further treatment, the well ordered SnO2 thin film is considered to have a potential application in gas-sensing materials. Remarkably, this may be a distinctive method to get SnO2 film and may be widely applied to produce other metallic oxide films with low density.