In this book, synthesis of metal and metal oxide nanostructures through the novel, simple and inexpensive electrical arc discharge in liquids presented. Important functional metal and semiconductor nanostructures such as ZnO, WO3, ZrO2, TiO2, Ag and Au were successfully produced. Also Ag-codoped TiO2 nanoparticles using a combination of top down arc discharge and bottom up sol-gel methods have synthesized. XRD and XPS results indicated formation of ZnO, WO3 and ZrO2 phase. TEM images revealed cubic WO3 and rod-like as well as semi spherical ZnO nanostructures. The particle size was found to increase with an increase in the arc current. Photocatalytic activity of produced nanostructures demonstrated that by increasing UV illumination time, the maximum absorption peak and concentration of Rh. B decreases in the presence of metal oxide nanostructures. In fact, decrease of concentration for ZrO2 was found to be more pronounced than the ZnO and WO3 which was due to increased surface to volume ratio. The present method can be used for the synthesis of various kinds of nanostructures from metal to metal oxide and compound nanomaterials.