Unlocking the Potential of N-Doped SnO2 for Sustainable Photocatalytic Degradation of Carcinogenic Dyes

Abstract

Environmental adulteration is an emerging concern due to the discharge of wastewater effluents from several sources. Several carcinogenic dyes are the major contaminants in these water bodies. These could cause long-lasting and detrimental effects to humans as well as aquatic ecosystems. For efficient degradation of such dyes, the exploration of nanotechnology has demonstrated huge potential. Herein, the degradation of dyes (MB, CV, and MO) has been carried out photocatalytically using N-doped SnO2 nanoparticles (N:SnO2 NPs) as well as in presence of a sacrificial agent, EDTA. These NPs were synthesized at an ambient temperature. Different characterization techniques were used throughout the analysis of the synthesized NPs. The PXRD analysis reveals formation of single-phase rutile structure with tetragonal symmetry. Using the Scherrer formula, the size of the NPs was found to be less than 5 nm, exhibiting increases in size with N doping. Further, morphological analysis through field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) examined the existence of highly agglomerated, spherical NPs. The thermogravimetric analysis (TGA) results depict the thermal stability of the synthesized NPs up to a temperature of 800 °C. These synthesized N:SnO2 NPs exhibit potent efficiency for the photocatalytic degradation of MB, MO, and CV dyes with an efficiency of 93%, 83%, and 73% degradation, respectively, under UV light irradiation. Additionally, the effect of the sacrificial agent, EDTA, was observed on the degradation process and resulted in a degradation of ~90% MB dye, 88% CV dye, and 86% MO dye within 15 min of UV light irradiation.

Photocatalytic Removal of Metronidazole Antibiotics from Water Using Novel Ag-N-SnO2 Nanohybrid Material

“…Moreover, the reason is the high elemental dispersion or the low concentration of either doping element [ 22 , 23 ]. The related materials′ average crystallite sizes were determined using the Debye-Scherrer formula [ 19 ] and are presented in Table 1 . From this, the estimated average sizes of the crystallite were 6.27 nm, 7.67 nm, 7.78 nm, and 6.92 nm for SnO 2 , Ag-SnO 2 , N-SnO 2 , and Ag-N-SnO 2 , respectively [ 19 , 20 ].…”

“…The related materials′ average crystallite sizes were determined using the Debye-Scherrer formula [ 19 ] and are presented in Table 1 . From this, the estimated average sizes of the crystallite were 6.27 nm, 7.67 nm, 7.78 nm, and 6.92 nm for SnO 2 , Ag-SnO 2 , N-SnO 2 , and Ag-N-SnO 2 , respectively [ 19 , 20 ]. The slope ( η ) of the Williamson–Hall (W-H) plot of β cos θ versus 4sin θ was used to calculate the crystal strains of SnO 2 , Ag-SnO 2 , N-SnO 2 , and Ag-N-SnO 2 [ 11 ].…”

“…Due to N doping, part of the O atoms in the SnO 2 lattice are replaced with N atoms. As a result, the absorption edge shifts to a lower energy because the N 2p orbitals overlapped with the O 2p orbitals in the valence band [ 19 ]. Figure 5 b shows that the estimated band gap energy for Ag-N-SnO 2 is 2.56 eV.…”

“…Additionally, at 368 eV and 373 eV, the two energy peaks are observed ( Figure 7 b), which are related to Ag 3d 5/2 and Ag 3d 3/2 for Ag 0 [ 9 , 23 ]. The binding energy centered at 413 eV in the deconvoluted core-level N 1s XPS spectrum ( Figure 7 c) indicates that N 3– is present in the lattice and can be attributed to the Sn-O-N linkage [ 19 ]. In the deconvoluted O 1s spectra ( Figure 7 d), the peak at 531.8 eV represents oxygen bound to C as C=O or C-O, whereas the other peak at 530.4 eV represent the lattice O 2– [ 10 ].…”

“…Furthermore, nitrogen (N) is one of the nonmetal dopants that effectively enhances semiconductor oxides′ absorption of light [ 15 ]. Bhawna et al reported that N-SnO 2 nanoparticles displayed significant photodegradation rates of methylene blue (93%) and methyl orange (83%) dyes under UV light exposure [ 19 ]. Siddique et al synthesized Ag/Bi/SnO 2 nanohybrid material using green chemistry route and documented photodegradation of methylene blue [ 20 ].…”