Enhanced photocatalytic activity of C-N-codoped TiO2 films prepared via an organic-free approach.

An organic-free sol-gel method was developed to synthesize crack-free, high surface roughness and visible-light-active C-N-codoped TiO(2) films. These films were subsequently evaluated for its photodegradation efficient using stearic acid as the model pollutant compound. The current approach avoids the use of hazardous organic solvents and employs carbon black as the carbon source as well as a template to increase the surface roughness. The presence of carbon and nitrogen species in TiO(2) was studied and discussed. The concentrations of carbon and nitrogen dopants in the TiO(2) films were affected by calcination temperature and the concentration of carbon black. Optimal visible light photocatalytic activity was observed for C-N-codoped TiO(2) film at 10.0 wt.% C, which was more than double that of the N-doped TiO(2) film. The enhancement in visible light photocatalytic activities of the C-N-codoped TiO(2) films was attributed to the synergistic effects of carbon and nitrogen dopants, and high surface roughness of the prepared films.

Superhydrophilicity-assisted preparation of transparent and visible light activated N-doped titania film.

A novel and environmental friendly method was developed to prepare transparent, uniform, crack-free and visible light activated nitrogen doped (N-doped) titania thin films without the use of organic Ti precursors and organic solvents. The N-doped titania films were prepared from heating aqueous peroxotitanate thin films deposited uniformly on superhydrophilic uncoated glass substrates. The pure glass substrates were superhydrophilic after being heated at 500 degrees C for 1 h. Nitrogen concentrations in the titania films were adjusted by changing the amount of ammonia solution. The optimal photocatalytic activity of the N-doped titania films was about 14 times higher than that of a commercial self-cleaning glass under the same visible light illumination. The current reported preparative technique is generally applicable for the preparation of other thin films.

Synthesis and characterization of sub-10 nm Platinum Hollow Spheres as electrocatalyst of direct methanol fuel cell.

Platinum Hollow Spheres (PHSs) with diameters less than 10 nm were successfully synthesized by using Co as a sacrificial template and H2PtCl6 as an oxidizing agent at 95 degrees C. The formation of PHSs at this temperature was not affected by citrate reduction and mainly depended on the pH. The results of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the platinum hollow sphere was mainly constructed by fcc (face cubic center) platinum with tiny crystallites on the shell. The performance of PHSs for methanol electro-oxidation was evaluated and compared with commercial E-TEK platinum black. Electrochemical measurement by cyclic voltammetry (CV) demonstrated that the electrochemical surface area of PHSs was about twice higher than E-TEK platinum black. Therefore, the synthesized PHSs had higher electrocatalytic activity for methanol electro-oxidation.