Photocatalytic Properties of PbMoO4 Nanocrystals against Cationic and Anionic Dyes in Several Experimental Conditions

This paper reports easy and fast synthesis of PbMoO4 nanocrystals by microwave-assisted hydrothermal (MH) method at different synthesis times (1, 10, 30 and 60 min) at 100 °C. X-ray diffraction, Rietveld refinement and Raman spectroscopy confirm all characteristics of diffraction peaks and active vibrational modes of the pure scheelite structure (tetragonal, I41/a) for all synthesized PbMoO4 nanocrystals. The optical bandgap calculated directly from the samples is close to 3.5 eV. The images collected by scanning electron microscopy show particles with mean length from 159.90(8) nm to 303.02(3) nm with greater exposure of planes (111), (100), (011) and (110). The photocatalytic activity of PbMoO4 nanocrystals against RhB and RBBR dyes resulted in successful degradation in short time intervals using ultraviolet light, where the best performance was achieved for the PbMoO4-10 sample, which was 29.2 and 51.8 times more effective than photolysis. The contribution of oxidant species was monitored by radical scavengers, which confirms that holes (h+) are the main oxidative species in photodegradation of RhB and RBBR dyes, while reuse of the catalyst against RhB and RBBR dyes confirms high stability of the catalyst, although recycled four times.