Synthesis of sub-5 nm Co-doped SnO2 nanoparticles and their structural, microstructural, optical and photocatalytic properties

Abstract

A swift chemical route to synthesize Co-doped SnO 2 nanopowders is described. Pure andcrystalline nanoparticles were synthesized, with mean grain sizes < 5 nm and the dopant element homogeneously distributed in substitutional sites of the SnO 2 matrix. The UV-visible diffuse reflectance spectra of the Sn 1-x Co x O 2- samples reveal red shifts, the optical bandgap energies decreasing with increasing Co concentration. The samples' Urbach energies were calculated and correlated with their bandgap energies. The photocatalytic activity of the Sn 1-x Co x O 2- samples was investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02% (w/w) of Sn 0.95 Co 0.05 O 2- nanoparticles in 60 min of irradiation.

Structural, optical, photocatalytic, and antimicrobial activities of cobalt-doped tin oxide nanoparticles

“…The redshift of band gap in doped samples can be attributed to the sp-d exchange interactions between the band electrons and the localized d electrons of the Co 2? ions substituting Sn 4? ions [8,28,29]. Fang et al [30] in their work reported that redshift in the band gap of Fe 3?…”

“…(r = 0.75 Å ) is larger than that of Sn 4? (r = 0.69 Å ) [8,25]. Figure 2a provides the TEM image of sample CT3 and the particle size distribution with log-normal profile and selected area diffraction (SAED) patterns in its inset, and Fig.…”

“…Casados et al [4] show that pure tin oxide has photocatalytic properties similar to that of commercial titanium oxide (Degussa P25) under UV light irradiation in the degradation of methylene blue (MB) for reaction times in the range 0-1 h. However, due to the large band gap observed for SnO 2 , it can be photoactivated only by UV irradiation which constitutes only 4-5 % of the entire solar energy, leaving most of the visible portion of solar radiation. This limitation can be overcome by doping SnO 2 with transition metal ions such as Co, Ni, and Mn that extends the absorption spectrum from UV to visible regions, and therefore, the solar energy could be used effectively [8,9]. In addition to photocatalytic activity, inorganic metal oxides such as TiO 2 , ZnO, and SnO 2 doped with transition metal ions have received increasing attention in antimicrobial applications because such materials can achieve effective disinfection without the formation of any harmful by-products [10][11][12][13][14].…”

Synthesis and Characterization of Tin Oxide: A Review

“…The crystal structure type of SnO 2 is similar to the rutile phase structure of TiO 2 (dimensions of the unit cell: a = b = 0.47374 nm and c = 0.31864 nm, polar crystal with octahedral and space group no. 136 P42/mnm In one unit cell, the tin(IV) ion is surrounded by 6 oxygen ions and every oxygen is bordered by 3 tin(IV) ions, resulting in a coordination structure [8][9][10] as shown in Figure 1. The discovery of the photocatalytic properties of TiO 2 also led to a range of proposals for photocatalytic applications of related oxides.…”

One-Pot Hydrothermal Synthesis of Sulfur-Doped SnO2 Nanoparticles and their Enhanced Photocatalytic Properties

“…As a result, the recombination of photo-induced electron-hole pairs is e®ectively inhibited, and the photocatalytic e±ciency is promoted by doping related trapped states. [35][36][37][38] Besides, the nonmetal doping is also an e®ective modi¯cation strategy for the improvement of visible-light-driven photocatalytic activity due to the bandgap narrowing. 34,[39][40][41] In particular, nonmetal doping such as N, C and S could make catalyst have better solar absorption and photocatalytic activity due to certain disadvantages of metal doping such as low thermal stability and enhanced recombination of charge carriers.…”