Promotion of TiO2 Nanotube-Confined Pt Nanoparticles via Surface Modification with Fe2O3 for Ethylene Oxidation at Low Temperature.

A modified confined catalyst with Pt nanoparticles on the interior and Fe2O3 on the exterior surface of TiO2 nanotubes (Pt-in/Fe2O3-TNTs) was prepared and investigated for catalyzing the oxidation of ethylene. Compared with the Pt-in/TNTs without Fe2O3 modification, the Pt-in/Fe2O3-TNTs exhibited a significantly enhanced activity, and the complete conversion temperature of ethylene decreased from 170 to 95 °C. X-ray photoelectron spectroscopy analysis indicated that the Pt nanoparticles were stabilized at higher oxidation states in the Pt-in/Fe2O3-TNT catalyst. It was proposed that the modification of Fe2O3 on the outer surface can tune the electronic state of the encapsulated Pt particles and accelerate the electrons transferred from Pt to Fe species via TiO2 nanotubes, thus improving the catalytic oxidation performance of the confined catalyst.