Thermal expansion coefficient determination of pure, doped, and co-doped anatase nanoparticles heated in sealed quartz capillaries using in-situ high-temperature synchrotron radiation diffraction

Abstract

Synchrotron radiation diffraction was conducted in-situ and at high temperature to establish the lattice parameters of pure/undoped, doped, and co-doped anatase nanoparticles. The nanoparticles were heated from room temperature to 950 °C in sealed quartz capillaries. The effect of pressure, doping (aluminium or indium), and co-doping (indium-chromium or silver-chromium) on the thermal expansion coefficients of nanocrystalline anatase was established. Synchrotron radiation diffraction at high temperature and in-situ , transmission electron microscopy, and the Rietveld refinement method were used to characterise the anatase nanoparticles. The anisotropy of the thermal expansion, α a /α c , for pressurised anatase nanoparticles was smaller than that for anatase heated in unpressurised air or argon, and it was much smaller in a vacuum.

Investigation of the Morphological, Structural, and Vibrational Behaviour of Graphite Nanoplatelets

“…Rietveld pattern-fitting of the XRD pattern was analysed from the FullProf software, and the goodness-of-fit was estimated from the derived Bragg R-factors (R B ), expected R-factor (R exp ), and weighted pattern R-factor (R wp ) [37][38][39][40][41][42][43]. The preferred orientation, peak shape parameters, lattice parameters, scale factor, 2θ 0 , sample displacement, and pattern background were optimized in the Rietveld refinement to calculate the GNP lattice parameters.…”

“…In this work, the residual Rietveld refinements were 5.62 and~11.9 for the R wp and R exp , respectively. The goodness-of-fit (χ 2 ) of 4.46 shows an acceptable refinement quality [37][38][39][40][41][42][43].…”

Synthesis and Characterization of Electrospun Carbon Nanofibers from Polyacrylonitrile and Graphite Nanoplatelets

“…Calculated and measured values are indicated by solid black lines and red circles, respectively; the residual difference between the two is shown by a blue plot, while the (002), (020), and (004) peak positions are shown by green bars. A 1.59 goodness-of-fit (χ 2 ) shows an excellent refinement quality (the ideal goodness-of-fit is 1.0) [ 32 , 38 ].…”

Wettability of Nanostructured Transition-Metal Oxide (Al2O3, CeO2, and AlCeO3) Powder Surfaces

“…The Scherrer equation was used to calculate the average crystallite size ( D XRD ) of TMOs [ 23 , 24 , 25 ]: where k , λ , β , and θ are shape factor (0.91), wavelength of the Cu-K α radiation (0.15419 nm), full width at half maximum (FWHM), and the Bragg diffraction angle, respectively.…”