Composite materials made from glass microballoons and ceramic nanofibers for use as catalysts and catalyst supports

Glass microballoons (GMBs) are commonly used to reduce the density of epoxy-resin syntactic foams, but they can also be applied as a low-cost and lightweight catalyst support. In order to create a practical structure that can be utilized for such an application, a ceramic syntactic foam consisting of glass microballoons (GMBs) and silica nanofibers (NFs) with or without TiO₂ binder was synthesized. The mechanical strength, phase composition, high-temperature deformation behavior, and microstructure of the composite material were analyzed using bending and compression tests, X-ray diffraction, and scanning electron microscopy, respectively. It was determined that the addition of nanofibers improves the thermal behavior and mechanical strength of the composite material during and after processing. The composite materials maintained up to 70% anatase titania at as high as 700 °C, and this indicates that they can be of interest for high-temperature catalysis. No high-temperature deformation of GMBs was observed at 800 °C or 1000 °C, whereas XRD of samples coated with TiO₂ using a titanium oxysulfate solution indicated the formation of cristobalite above 800 °C. Preliminary methane-reforming experiments were performed with NiO-seeded titania-coated GMBs, uncoated GMBs, and an uncoated silica fibers/GMBs composite. Uncoated GMBs and titania-coated GMBs had a low conversion ratio of methane to products, but the uncoated composite structure showed high conversion of the reactants at high temperatures, indicating that it may be suitable catalyst support in this reaction.