Synthesis and characterization of BiOCl-CoWO4 nanocomposites with improved photocatalytic activity

We have synthesized novel BiOCl-CoWO4 heterostructured nanocomposites through chemical precipitation route with different amount of CoWO4 using KCl as Cl source at a temperature of 100 degrees C, 4 hours. X-ray diffraction, transmission electron microscopy, UV-visible NIR spectroscopy, photoluminescence spectroscopy, N-2 adsorption-desorption isotherms, and electrochemical impedance spectroscopy were performed to gain the crystal structure, morphology, optical properties, surface area, and charge separation of the prepared photocatalysts. BiOCl-CoWO4 composites demonstrated the diffraction peaks of both monoclinic CoWO4 nanoparticles and tetragonal BiOCl indicating the formation of the nanocomposite. TEM observations have shown that CoWO4 nanoparticles were deposited on the BiOCl surface. Photoluminescence, fluorescence lifetime study, and Electrochemical impedance spectroscopy responses of materials indicated a good separation efficiency of charge carriers in BiOCl-CoWO4-1. The photodegradation efficiency of the prepared materials was assessed by the decomposition of rhodamine B (RhB) dye solution under sunlight irradiation. Among the synthesized materials, the BiOCl-CoWO4-1 composite photocatalyst exhibited maximum photocatalytic activity. Thus the resulting heterostructure favored the efficient charge and energy transfer between BiOCl and CoWO4 nanoparticles across the interface. The investigations from the radical scavenger tests showed that photogenerated h(+), O-2(center dot)-, and (OH)-O-center dot radicals were involved in the photodegradation of RhB.