ZrO2 particles with different microstructure have been fabricated through an easy method with chitosan of different molecular weights as template. The chitosan of different molecular weights was obtained through synergistic degradation of raw chitosan by alpha-amylase and H2O2 using microwave hydrothermal method in low concentration acetic acid (1% V/V). The as-synthesized ZrO2 particles were characterized by wide-angle powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and N-2 adsorption-desorption. The possible formation mechanism of ZrO2 particles with different microstructure has been proposed, and the photocatalytic activity of the as-synthesized products was assessed by monitoring the photodegradation of Rhodamine B (Rh B) under UV irradiation. Morphologies of as-synthesized ZrO2 particles changed significantly with the different molecular weight of chitosan. As the molecular weight of chitosan decreased, the morphologies of as-synthesized ZrO2 particles showed aggregate, nano-cubes, and nano-sheets, respectively. The ZrO2 particles prepared with lower molecular weight chitosan as the template showed higher photocatalytic activity. The degradation efficiency of ZrO2 with 3.1 x 10(7) and 2.4 x 10(4)Da chitosan as template was 64.4% and 86.2%, respectively. (C) 2016 Elsevier Ltd. All rights reserved.