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Abstract
Multifunctional rare-earth-based materials have been widely studied and their performances rationally designed by tuning composition, morphology and crystallinity. Specifically, Praseodymium (Pr) based materials with unique 4f electron structure and reversible valence change property are a promising multifunctional candidate for numerous applications. There have been several investigations into this ranging from a solution-based method to a solid-state reaction and these have been introduced to synthesize Pr based structures. However, adequate control of morphology remains unclear and many show poor crystallinity and irregular morphology.
Pr-based nano-micro structures with controlled morphology were fabricated by facile wet-chemical routes and the systematic study of reaction parameters such as precursor, solvent and temperature were investigated to modify the properties. The morphology-dependent performance, including photocatalytic degradation, catalytic oxygen evolution reaction and energy storage, were confirmed.
One-dimensional (1-D) Pr(OH)3 nanorods with good crystallinity were fabricated and nanorods with a high aspect ratio displayed a better photocatalytic degradation of organic dye compound which also suggest the {100} crystal planes were more active. In addition to this, the Pr(OH)3 thin film with three-dimensional (3-D) structure was assembled by the 1-D nanorods and the effects of different reaction conditions were studied. It was found that the alignment of the nanorods played a vital role in the redox process. The polyhedral microrods and uniform nanospheres PrCO3OH were synthesized and the selectively exposed crystal facet contributed mainly to the redox properties rather than the size effect. The Praseodymium oxides were found to have different oxygen-levels and a novel 3-D hierarchical nanocomposite was produced for energy storage application. This study provides a new direction towards developing Pr-based multifunctional materials by wet-chemical methods.