The synthesis of ZnO/SnO2 porous nanofibers for dye adsorption and degradation.

ZnO/SnO2 hetero-nanofibers about 250 nm in diameter and several micrometers in length are synthesized via an electrospun method using zinc chloride and stannous chloride as inorganic sources. All fibers are composed of many nanoparticles (5-10 nm) that induce a highly porous structure as well as high surface area. By adjusting the ratio of zinc/stannous source, the synthesized porous ZnO/SnO2 materials show various structures (corrugated fiber and tube), that are a result of the different oxidation/decomposition temperatures of the two components. Their photodegradation abilities toward various dye wastewaters (methylene blue, congo red, eosin red, and methyl orange) are demonstrated, showing fast photodegradation and good recycling ability. It is noteworthy that ZnO/SnO2 exhibits an enhanced photodegradation ability to congo red, ascribed to the high adsorption capacity derived from the strong electrostatic interaction between ZnO/SnO2 and congo red. Based on the investigation, these porous ZnO/SnO2 hetero-nanofibers possess versatile potential applications for wastewater purification.