Fe3O4/SiO2/TiO2 Core-Shell Nanoparticles as Catalyst for Ag(I) Ions

Abstract

Nanosized-photocatalysts with additional magnetic functionality have been studied extensively for many potential applications. Fe 3 O 4 /SiO 2 /TiO 2 core-shell nanoparticles have been evaluated as catalyst for photoreduction of aqueous solution of Ag(I) ions. The nanoparticles was prepared by coating Fe 3 O 4 with SiO 2 and TiO 2 consecutively through sol-gel process followed by microwaveassisted treatment. The prepared nanoparticles were confirmed by XRD and TEM. A photocatalytic reaction was carried out in a batch system with a UV-irradiation wavelength of 340-390 nm. The effects of catalyst loading, irradiation time and solution pH were studied. The Ag(I) photoreduction progress was monitored by AAS. The obtained Fe 3 O 4 /SiO 2 /TiO 2 core-shell nanoparticles can reduce 97% of Ag(I) in the solution whereas unmodified TiO 2 solids can only reduce 37% of the ion. The photocatalytic reaction could be best performed at pH 6, irradiation time of 2 h, and initial Ag(I) concentration of 25 mg/L. The prepared materials could be of interests in the treatment of waste containing toxic heavy metal ions.

Photocatalytic Reduction of AuCl4- by Fe3O4/SiO2/TiO2 Nanoparticles

“…Peaks of the anatase phase of TiO2 appear at 25.22°, 48.36, and 54.22 on the diffraction pattern of Fe3O4/SiO2/TiO2. A similar result was also reported by previous studies (Kunarti et al, 2016;Kunarti et al, 2017) and literatures (Schatz et al, 2009;Xue et al, 2013).…”

“…It is clearly not caused by competition in the photoreduction, but it prominently caused by adsorption of Ni 2+ on the surface of TiO2. As presented previously, the photocatalytic reduction process is always initiated and/or accompanied by adsorption on the surface of photocatalyst (Wahyuni et al, 2015;Kunarti et al, 2017). When AuCl4 − in the solution is along with Ni 2+ and Cu 2+ ions, the adsorption of the three ions should be involved.…”

“…Magnetite, Fe3O4, and Fe3O4/SiO2 nanoparticles were prepared according to the previous work (Kunarti et al, 2017) with slight modification. They were synthesized through a sol-gel method.…”

“…The SiO2 layer with porous structures enables the surface area to increase and to facilitate better access for target species to reach the active site of the material (Ullah et al, 2015). Several studies on addition of SiO2 layer to the Fe3O4/TiO2 nanocomposite show a better performance in photooxidation of organic compounds such as sucrose (Beydoun and Amal, 2002), methyl orange (Gad-Allah et al, 2007), acetaminophen, antipyretin, caffeine, metoprolol, bisphenol A (Álvarez et al, 2010), methylene blue (Kunarti et al, 2016) and photoreduction of silver(I) ions (Kunarti et al, 2017). We have been working on the photocatalytic reduction of metallic ions (Kunarti et al, 2017;Fajri, 2017).…”

Synthesis and Application of Fe₃O₄/SiO₂/TiO₂ Nanocomposite as Photocatalyst in CO₂ Indirect Reduction to Produce Methanol

“…This property was perfectly matched with photocatalyst because photocatalysis occurs in a heterogeneous system where this property enhances the recovery of the photocatalyst. The magnetic photocatalyst reduction was studied in our former research [16][17], gave a good result in metal photoreduction under UV irradiation. The others [18][19] even responsive to visible light in metal photoreduction.…”