Proton conduction properties of hydrous sulfated nano-titania synthesized by hydrolysis of titanyl sulfate

The proton conduction properties of sulfuric acidmodified nano-titania prepared by impregnation method were investigated. The proton conductivity of sulfuric acid-modified nano-titania was almost the same as that of hydrous sulfated nano-titania investigated in our previous work when the amount of adsorbed sulfate groups was almost the same. The highest conductivity was obtained at an adsorbed sulfate group amount of 0.42 mmol/g, not 0.97 mmol/g. This result indicates that the enhancement of conductivity with increasing amount of adsorbed sulfate groups is limited. This might be attributable to insufficient water molecule adsorption on the Ti 4+ site coordinated with a bidentate sulfate group due to the prevention by excess sulfuric acid.

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