Preparation of a fiberglass-supported Ni-Si-Ti oxide catalyst for oxidation of hydrocarbons: effect of SiO₂

BACKGROUND: Preparation of homogeneous oxide coatings on the surface of fiberglass is a difficult task due to hydrophobicity of the fiberglass support. NiO-TiO₂ cannot coat the fiberglass surface homogeneously. In the present study, SiO₂ was added in the NiO-TiO₂. A sol–gel method was used to prepare Ni-Si-Ti sol and this was used to coat fiberglass and form a complex Ni-Si-Ti oxide system supported on its surface. The catalyst was tested for hydrocarbon oxidation reaction. RESULTS: The as-prepared material is a mixture of TiO₂ in the anatase modification and SiO₂ in the amorphous phase. UV-visible diffusion reflectance spectroscopy confirmed the presence of Ni²⁺ _Oh cations in the film bulk. Introduction of silica to the sample ensured a uniform distribution of the NiTi oxide system on the fiberglass surface and its durable retention there at 600 °C. The Ni-Si-Ti mixed oxide supported on fiberglass demonstrated a higher catalytic activity in the oxidation of n-heptane, compared to NiTi oxide/fiberglass catalyst. It is stable even at 600 °C, the temperature at which the maximum n-heptane conversion of 93% was reached. CONCLUSION: Adding SiO₂ in NiO-TiO₂ can coat fiberglass homogeneously as SiO₂ can coat hydrophobic surfaces such as fiberglass. This research provides a method with which to coat metal oxide catalyst on fiberglass that is very active and stable for oxidation of hydrocarbons even at high temparatures, compared to that without adding SiO₂.