preparation and characterizations of cuo doped zno nano-structure for the photocatalytic degradation of 4-chlorophenol under visible light

in present investigation, zno nanostructure was synthesized by means of a precipitation and sonochemical methods. the x-ray diffraction (xrd) pattern is shown that the wurtzite structure of zno has the hexagonal symmetry and there is no impurity. the average zno particles crystallite size was calculated about 41 nm. the sem and tem images reveal nanostructure zno particles with a cauliflower-like and rod morphology with dimensions of 85, 79 and 117 nm. in order to increment of zno photoactivity under visible light, cuo doped zno nanostructures were fabricated by wet impregnation method using copper oxide as copper source and zno as the precursor. the xrd analysis confirms that cuo phase is present in the as-prepared sample and the average size of nano crystalline decreased to about 36nm. drs spectra indicated the extended absorption of cu-zno to the visible range as a result of band gap reduction to 2.9 ev (in comparison of 3.2 ev in zno). in order to investigate of photocatalytic activity of synthesized photocatalyst, degradation of 4-chlorophenol under visible light was done. sixteen experiments using full factorial were done by adjusting four parameters (amount of catalyst, initial concentration of 4-cp, ph, and time of irradiation). an empirical expression was proposed and successfully used to model the photocatalytic process with a high correlation, and an optimal experimental region was also obtained. from the developed model for degradation and subsequent anova test using design expert software, time of irradiation with 46.57% effect played the most important role in the photocatalytic activity, while the influences of parameters on each other were negligible. optimal experimental conditions for 4-chlorophenol concentration (0.01 g l−1) were found at initial ph =8 and catalyst loading of 0.07 g l−1. results showed that cu-zno can remove 95% of 4-chlorophenol from water in the optimal conditions.