THERMALLY STABLE NANO-COMPOSITE OF ZRO2/MWCNT WITH STRONG INTERFACIAL INTERACTION AND TUNABLE PARTICLE SIZE

This research is focused on the synthesis and characterization of a composite of ZrO₂ nanoparticles uniformly decorating multi-walled carbon nanotubes (MWCNT) with high dispersion. Using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM), the ZrO₂ were found to be 2-3 nm tetragonal crystalline nanoparticles. Strong interfacial interaction between the ZrO₂ nanoparticles and the MWCNT surface was observed by near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at the carbon K-edge and the oxygen K-edge, and this strong metal-oxide/support interaction through oxygen functionalities on the MWCNT surface leads to small ZrO₂ particle size and thermal stability. The ZrO₂ particle size can be well tuned by varying ZrO₂ loading and annealing temperature, as studied by XRD, HR-TEM, in-situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS), and NEXAFS. Such materials can be turned into solid acid catalysts by sulfur impregnation (S-ZrO₂/MWCNT), which has potential applications in fuel cells and biomass processing.