Abstract: PVP/[La(NO3)3-Cr(NO3)3] composite nanobelts were fabricated via the combination of sol-gel method with electrospinning.  LaCrO4 nanobelts and LaCrO3 nanobelts were obtained by calcination of the relevant composite nanobelts at different temperature for 8 h.  The samples were characterized by thermogravimetric-differential thermal analysis(TG-DTA),  X-ray diffractometry(XRD),  scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS).  It was found that the surface of the composite nanobelts was smooth,  and the width and thickness were (9.1±1.9) μm and 385 nm,  respectively.  Monoclinic monazite LaCrO4 nanobelts were prepared when the composite nanobelts were calcined at 600  ℃.  The width of LaCrO4 nanobelts was (2.5±0.5) μm,  and the thickness was ca. 100 nm.  Orthorhombic LaCrO3 porous nanobelts with space group Pbnm were formed by calcination of PVP/[La(NO3)3-Cr(NO3)3] composite nanobelts at 650—800  ℃.  The width and thickness of LaCrO3 nanobelts obtained by calcination of composite nanobelts at 650  ℃ were (2.4±0.5) μm and 90 nm,  respectively.  Some of LaCrO3 nanobelts was broken into LaCrO.3 nanoparticles at 800  ℃.  The width of LaCrO3 nanobelts was (1.3±0.4) μm,  and the thickness was about 90 nm,  while the mean diameter of LaCrO3 nanoparticles was ca. 80 nm.  The photocatalytic activities of LaCrO4 nanobelts and LaCrO3 nanobelts were studied using rhodamine B as degradation agent.  In the presence of LaCrO3 nanobelts obtained at 800  ℃,  the best degradation result of rhodamine B was achieved by illumination of ultraviolet ray,  and the degradation rate of rhodamine B reached  94.6% after the reactive mixture was illuminated for 200 min.

Key words: Electrospinning, LaCrO4, LaCrO3, Nanobelt, Photocatalysis