Pd nanoparticles entrapped in TiO₂ nanotubes for complete butane catalytic combustion at 130 °C

Abstract

Air pollution by volatile organic compounds is a major health issue due to increasing industrialization and urbanization, notably in the developing countries. Cleaning organic pollutants by catalytic combustion is a potential solution, but actual methods require relatively high temperatures, thus increasing remediation costs. There is therefore a need for methods that operate at mild temperatures. Here we prepared a novel catalyst made of Pd nanoparticles entrapped in TiO₂ nanotubes by vacuum-assisted impregnation. Then, we tested this catalyst for butane combustion. The catalyst was characterized by N₂ adsorption–desorption isotherms, transmission electronic microscopy, energy-dispersive X-ray analysis coupled with a scanning transmission electron microscope, X-ray photoelectron spectroscopy and temperature programmed oxidation. Results show a complete combustion of butane at 130 °C, which is about 20 °C lower than temperatures required by actual catalysts made of Pd nanoparticles deposited on the exterior surface of TiO₂ nanotubes. Structure characterization suggests that this higher performance at lower temperature is explained by the confinement of TiO₂ nanotubes. Such a confinement could hinder the metal sintering and, in turn, facilitate the formation of PdO during oxidation on the entrapped Pd nanoparticles.