ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis and properties of Sn-doped α-FeOOH nanoparticles

Nina Popov, Mira Ristić, Marko Robić, Vanja Gilja, Ljerka Kratofil Krehula, Svetozar Musić, and Stjepko Krehula

Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia

E-mail: krehul@irb.hr

Received: 15 March 2021  Accepted: 19 July 2021

Abstract:

Pure and Sn-doped goethite (α-FeOOH) nanoparticles with good uniformity were synthesized by a facile precipitation method. The effects of Sn doping on the particle size and shape, structural, thermal, vibrational, optical and photocatalytic properties of prepared goethite nanoparticles were investigated. The Sn⁴⁺-for-Fe³⁺ substitution in the crystal structure of goethite was proved by determination of a significant unit cell expansion (the effect of larger Sn⁴⁺ ions) and a substantial reduction of the hyperfine magnetic field (the effect of magnetic dilution by non-magnetic Sn⁴⁺ ions). Sn doping induced a decrease in length and an increase in thickness of goethite nanocrystallites and nanoparticles, i.e., the change in particle shape from thin goethite nanorods to shorter and thicker Sn-doped goethite nanoellipsoids and nanocuboids. Thermal dehydroxylation of goethite was shifted to significantly higher temperatures by the Sn⁴⁺-for-Fe³⁺ substitution. The optical band gap of goethite nanoparticles narrowed with the increased Sn⁴⁺-for-Fe³⁺ substitution. The visible light photocatalytic efficiency for rhodamine B (RhB) degradation by a heterogeneous photo-Fenton process was gradually enhanced by Sn doping from 38% for pure goethite nanorods to 55% for Sn-doped nanoellipsoids and 70% for Sn-doped goethite nanocuboids.

Keywords: Goethite; Mössbauer spectroscopy; Nanoparticles; Optical band gap; Sn dopant; Visible light photocatalyst

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01802-9

Chemical Papers 75 (12) 6355–6366 (2021)