Morphology adjustment of one dimensional CeO2 nanostructures via calcination and their composite with Au nanoparticles towards enhanced catalysis

Abstract

One dimensional (1D) CeO₂ nanostructures have been successfully fabricated via a single nozzle electrospinning method and subsequent two-step calcination route by adjusting heating rates. The formation process of CeO₂ nanotubes (NTs) and nanobelts (NBs) was investigated by observing the morphology evolution of fibers during calcination. Control of the heat-treatment procedure including solvent evaporation, the Kirkendall effect, polymer softening, and thermal decomposition of poly(vinylpyrrolidone) plays an important role in the morphologies of the samples. Well-dispersed and small Au nanoparticles (NPs) were deposited on 1D CeO₂ nanostructures through a direct wet-chemical reaction or adding Au precursors during electrospinning. The results of the catalytic performance for CO oxidation suggest that CeO₂ NTs display enhanced catalytic activities compared with CeO₂ NBs. The loading of Au NPs significantly enhanced the catalytic properties of 1D CeO₂ nanostructures. Because of the large surface areas, good crystallinity and the strong interfacial interactions between Au NPs and the CeO₂ matrix, the 1% Au/CeO₂ NTs exhibit superior catalytic activity with onset CO conversion at 65 °C and complete CO conversion at 142 °C.