Semiconductor Photocatalyst of Tin Oxide Quantum Dots Prepared in Aqueous Solution for Degradation of Organic Pollutants in Contaminated Water

Abstract

Stannous chloride and thiourea are used as source materials to prepare SnO₂ quantum dots in the aqueous solution by a facile hydrolysis-oxidation process. The quantum dots have an average size of 1.9 nm with good dispersibility as well as long-term stability, and are validated to be an effective photocatalyst for the degradation of organic oil pollutants in contaminated water. The pollutant is removed by the quantum dots exposed to ultraviolet-visible irradiation at room temperature. The optimized condition is concluded to be a solution with quantum dot concentration of 10^-3 mol/L and the degradation speed reaches the maximum at the 12 th hour after irradiation. After 48 hours, 91.9 % of octane is removed, concluding a high degradation efficiency. The prepared SnO₂ quantum dots are potentially applicable in the remediation of marine environment as they hold the advantages of high efficiency, low cost and being environmental-friendly. The promotion and inhibition mechanisms of the photocatalytic SnO₂ QDs at low and high concentrations are discussed.