Synthesis of Hexahydroxy Strontium Stannate/Tin Dioxide Nanocomposites and Their Photocatalytic Properties for Gentian Violet

Background: Gentian violet dye released from industries into the environment has caused serious water pollution and is a significant environment pollutant to human beings owing to the toxicity. It is urgent to decrease the environmental pollution by removing gentian violet in the wastewater. Objective: The aim is to synthesize hexahydroxy strontium stannate/tin dioxide nanocomposites by a simple hydrothermal method without surfactants and research the photocatalytic performance for gentian violet degradation. Methods: Hexahydroxy strontium stannate/tin dioxide nanocomposites have been obtained via the hydrothermal method. The structure, size, morphology and photocatalytic performance were characterized by X-ray diffraction, electron microscopy, solid ultraviolet-visible diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. Results : The nanocomposites possess oven-shaped morphology with the size of less than 100 nm and are composed of hexagonal SrSn(OH)6 and tetragonal SnO2 phases. The band gap of the nanocomposites is 3.52 eV. 10 mg hexahydroxy strontium stannate/tin dioxide nanocomposites have the ability to completely degrade 10 mL gentian violet solution with the concentration of 10 mgL-1 under 6 h ultraviolet-visible light irradiation. Hydroxyl radical, hole and superoxide radical are main species for the gentian violet photocatalytic degradation using the nanocomposites. Conclusion: The hexahydroxy strontium stannate/tin dioxide nanocomposites show good photocatalytic performance for the GV degradation. The photocatalytic performance for gentian violet degradation using the hexahydroxy strontium stannate/tin dioxide nanocomposites depends on the irradiation time and content of the nanocomposites.

Synthesis of nanocomposites based on strontium stannate

From hydrochloric acid solutions of strontium and tin(IV) by addition of ammonia until pH = 10 was obtained double hydroxide of strontium-tin(IV) SrSn(OH)6. The process of double hydroxide thermolysis and the phase composition of decomposition products were studied by differential thermal analysis, X-ray diffraction and scanning electron microscopy. It is shown that the main dehydration step is completed at a temperatureofnearly350°CandX-rayamorphousproductisformed which converts into the crystalline phase of strontium stannate at a temperature above 650°C.