Synthesis and doping of nickel and zinc tungstate with group 11 elements for the analysis of photocatalytic properties

Abstract

This study presents two metal tungstates, nickel (NiWO4) and zinc (ZnWO4), modified with silver and copper respectively. It has been found that doping of nickel tungstate with silver was not possible through coprecipitation methods due to a dopant migration effect which deposits silver onto the surface of the catalyst. Surfactant mediated hollow NiWO4 nanostructures were also synthesized in the presence of silver through a soft template method. Both these modified NiWO4 structures showed increased photodegradation of methylene blue dye under UV irradiation normalized by mass. The zinc tungstate samples showed homogeneity of copper dispersed throughout the crystal without forming a heterostructure. It was shown that a competition between dopant types causes low doping of ZnWO4 with copper to be inactivated, while higher amounts increase the activity of the tungstate under UV irradiation.