Use of NiO/SiO2 catalysts for toluene total oxidation: Catalytic reaction at lower temperatures and repeated regeneration

Abstract

We deposited NiO via atomic layer deposition on mesoporous SiO2 particles with diameters of several hundred micrometers and a mean mesopore size of ∼14 nm. NiO was deposited within the shell region of mesoporous SiO2 particles with a shell thickness of ∼11 mm. We annealed the as-prepared NiO/SiO2 at 450 and 600 °C, respectively. These two samples were used as catalysts for the uptake of toluene molecules and their oxidative conversion to CO2. The sample annealed at 450 °C was generally more reactive in toluene uptake and its subsequent conversion to CO2. When the NiO/SiO2 annealed at 450 °C was exposed to toluene vapor at 160 °C and then heated to 450 °C, CO2 was emitted with almost no toluene desorption. We suggest that our catalysts can be used as building blocks for odor removal devices that operate below 200 °C. These catalysts can be regularly regenerated at ∼450 °C.