Structural, negative thermal expansion and photocatalytic properties of ZrV2O7: a comparative study between fibers and powders

Novel ZrV2O7 microfibers with diameters about 1–3 μm were synthesized using a sol–gel technique. For comparison, ZrV2O7 powders were prepared by the same method. The resultant structures were studied by X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy. The results indicated that both the pure ZrV2O7 microfibers and powders could be synthesized by the sol–gel technique. The thermal expansion property of the as-prepared ZrV2O7 microfibers and powders was characterized by a thermal mechanical analyzer, both the fibers with cylindrical morphology and irregular powders with average size between 100 and 200 nm showed negative thermal expansion between 150 °C and 600 °C. The photocatalytic activity of the microfibers was compared to that of powders under UV radiations. The band gap of ZrV2O7 microfibers decreased and its absorption edge exhibited red shift. The microfibers also had a higher surface area compared with the powders, resulting in considerably higher photocatalytic characteristics. The large surface area and the enhanced photocatalytic activity of the ZrV2O7 microfibers also offer potential applications in sensors and inorganic ion exchangers.