Eu2+ and Eu3+ doubly doped ZnWO4 nanoplates with superior photocatalytic performance for dye degradation

Abstract

Eu2+ and Eu3+ doubly doped ZnWO4 nanoplates with highly exposed {100} facets were synthesized via a facile hydrothermal route in the presence of surfactant cetyltrimethyl ammonium bromide. These ZnWO4 nanoplates were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrometry, diffuse UV-vis reflectance spectroscopy, photoluminescence spectrophotometry, and photoluminescence lifetime spectroscopy to determine their morphological, structural, chemical, and optical characteristics. It is found that Eu-doped ZnWO4 nanoplates exhibit superior photo-oxidative capability to completely mineralize the methyl orange into CO2 and H2 O, whereas undoped ZnWO4 nanoparticles can only cleave the organic molecules into fragments. The superior photocatalytic performance of Eu-doped ZnWO4 nanoplates can be attributed to the cooperative effects of crystal facet engineering and defect engineering. This is a valuable report on crystal facet engineering in combination with defect engineering for the development of highly efficient photocatalysts.