Effect of pH value on H2Ti2O5/TiO2 composite nanotubes as Pt catalyst support for methanol oxidation

• Products are gradually converted from “H2Ti2O5·H2O” to “anatase TiO2” with the decrease of pH value.
• pH value of acid treatment is the most essential for the composition of HTNTs.
• Hydrogenotitanate/titania composite nanotubes (HTNTs) are used as catalyst supports.
• Pt/C-HTNTs prepared at the pH value of 7 exhibits the best electrochemical activity and stability.
• The enhanced performance of Pt/C-HTNTs could be attributed to the combined effect.

Hydrogenotitanate/titania composite nanotubes (HTNTs) are synthesized from anatase titania power via hydrothermal process at various pH values of acid treatment. The change of HTNTs components is investigated in detail by X-ray diffraction (XRD), energy dispersive analysis of X-ray (EDAX), which reveal that the products are gradually converted from “H2Ti2O5·H2O” phase to “anatase TiO2” phase with the decrease of pH values. Pt based catalysts are prepared by microwave-assisted ethylene glycol method. The effects of pH values on the performance of Pt/C-HTNTs catalysts have been mainly investigated. It has been found that the distribution and electrocatalytic properties of platinum nanoparticles are sensitive to the pH value of acid treatment. The Pt/C-HTNTs catalyst prepared at the acid treatment pH value of 7 exhibits the better electrochemical activity and stability than other catalysts.

The catalyst at the acid treatment pH of 7 exhibits higher electrochemical activity and stability than other catalysts, which is attributed to the combined effect of the distribution of Pt nanoparticles, the number of three-phase interfaces and the electronic conductivity.Figure optionsDownload as PowerPoint slide