Zhaoyue Liu

Multichannel TiO2 hollow fibers with enhanced photocatalytic activity

This work describes that the photocatalytic activity of microsized TiO2 fibers for degrading gaseous acetaldehyde can be systematically enhanced by introducing nanostructured interior hollow channels, which is achieved by a facile multifluidic electrospinning method. The increased channel number augments the BET surface area of TiO2 fibers intuitively. A quite interesting phenomenon is that the percentage increase for photocatalytic activity is higher than that for surface area. It is thus proposed that the multichannel hollow structures induce not only an inner trap effect on gaseous molecules, but also a multiple-reflection effect on incident light, which further improves the photocatalytic activity of TiO2 hollow fibers.

Fibrous TiO2–SiO2 nanocomposite photocatalyst

The electrospinning method is employed to prepare a fibrous TiO2-SiO2 (Ti : Si = 1 : 2) nanocomposite photocatalyst, in which Degussa P25 T i O2 nanoparticles are embedded inthe body of SiO2 fibers and which shows good photocatalytic activity due to its 3-D open structure, as evidenced by photocatalytic reduction of silver ions and decomposition of acetaldehyde.

A transparent and photo-patternable superhydrophobic film

A transparent superhydrophobic TiO2 film, prepared by spin-coating a TiO2 slurry on a glass substrate and modifying the resultant TiO2 film with fluoroalkylsilane molecules, was patterned by illumination with ultraviolet light through a photomask, producing a superhydrophobic/superhydrophilic surface micropattern with very small superhydrophilic areas, which we were able to selectively fill with alginate hydrogel.

Assembly of self-assembled monolayer-coated Al2O3 on TiO2 thin films for the fabrication of renewable superhydrophobic-superhydrophilic structures.

A renewable superhydrophobic-superhydrophilic pattern with a minimum dimension of 50 microm is prepared from octadecyltrimethoxysilane self-assembled monolayer-covered superhydrophobic Al2O3 overlayers on a superhydrophilic TiO2 surface via self-assembly and calcination of boehmite (AlOOH.nH2O) particles. The resulting Al2O3 layer plays dual roles as a superhydrophobic layer and as a UV-blocking layer for the underlying TiO2.

Photocatalysis-Triggered Ion Rectification in Artificial Nanochannels Based on Chemically Modified Asymmetric TiO2 Nanotubes

Ion rectification is one of the important characteristics of biological ion channels. Inspired by the function of biological ion channels, creation of artificial nanochannels that show analogous ion rectification characteristics has attracted a great interest recently. Herein, we demonstrate a new type of artificial solid-state nanochannel with ion rectification characteristics. The creation of artificial nanochannels includes the formation of asymmetric TiO2 nanotubes by electrochemical anodization of Ti metal, followed by chemical modification with octadecyltrimethoxysilane (OTS) molecules. The carboxylic groups are introduced onto the tip side of TiO2 nanotubes via photocatalytic decomposition of OTS molecules by TiO2 photocatalysis under ultraviolet light. When the radius of tip side of TiO2 nanotubular channels is comparable to the thickness of electric double layer, the negatively charged surface in neutral electrolyte in combination with the asymmetric pore geometry contributes to the ion rectification characteristics. Compared with previous artificial nanochannels, our new type of artificial nanochannel is more facile to fabricate and behaves as a diode that rectifies the ion transport, which also shows some other potential applications, such as sensor and separation materials.