Environmental remediation from aqueous mercury (II) by photocatalytic reduction using a coupled SnO₂–Co₃O₄ nanocomposite

Abstract

Coupled SnO₂–Co₃O₄ nanocomposite has been prepared by a simple co-precipitation method. The prepared coupled composites were tested for photocatalytic reduction of Hg²⁺ under visible light. The characterization of catalyst properties was done by the means of X-ray diffraction, Brunauer–Emmett–Teller, transmission electron microscopy, and ultraviolet–vis spectra. The presence of Co₃O₄ in a SnO₂ composite can change the surface properties to achieve sensitivity to visible light. A coupled SnO₂–Co₃O₄ nanocomposite can eliminate the recombination of electron-hole pairs in the catalyst. The results demonstrated that the optimum mol% of SnO₂:Co₃O₄ was 1:3, as this resulted in the greatest performance of the photocatalyst and a reduction of about 100% of Hg²⁺ in a 100 ppm solution in just 30 min. Additionally, the quantum yield for Hg formation by 1Sn:3Co sample is higher than that of Co and Sn samples by about one and six times, respectively.

Keywords:

• A coupled SnO₂–Co₃O₄
• Nanocomposite
• Visible photocatalyst
• Mercury