Synthesis of Pr-doped ZnO nanoparticles: Their structural, optical, and photocatalytic properties**Project supported by the International Cooperation Program of the Ministry of Science and Technology of China (Grant No. 2015DFR00720), the Cooperation Program of Wuhan Science and Technology Bureau, China (Grant No. 2016030409020219), and the Shenzhen Committee on Science and Technology Innovation, China (Grant No. JCYJ20170818112901473).

Abstract

Undoped and praseodymium-doped zinc oxide (Pr-doped ZnO) (with 2.0-mol%–6.0-mol% Pr) nanoparticles as sunlight-driven photocatalysts are synthesized by means of co-precipitation with nitrates followed by thermal annealing. The structure, morphology, and chemical bonding of the photocatalysts are studied by x-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive x-ray emission spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR), respectively. The optical properties are studied by photoluminescence (PL) and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). We find that Pr doping does not change the crystallinity of ZnO; but it reduces the bandgap slightly, and restrains the recombination of the photogenerated electron–hole pairs. The photocatalytic performance of the photocatalysts is investigated by the photodegradation reaction of 10-mg/L rhodamine B (RhB) solution under simulated sunlight irradiation, showing a degradation rate of 93.75% in ZnO doped with 6.0-mol% Pr.