Enhanced Photocatalytic Activity of ZnO Toward the Degradation of Methylene Blue Dye: Effects of Fe³⁺ and Sn⁴⁺ Doping

Abstract

ZnO, Fe 0.01 ZnO, Sn 0.05 ZnO, and Fe 0.01 Sn 0.01 ZnO photocatalysts are prepared by a simple low-temperature solution method using Zn(NO 3 ) 2 , Fe(NO 3 ) 3 , SnCl 4 , and NaOH as raw materials. X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area analysis, X-ray photoelectron spectroscopy, ultraviolet-visible diffusion spectroscopy, and photoluminescence spectroscopy are performed to characterize the products. All doped ZnO samples exhibit enhanced photocatalytic activity compared with undoped ZnO toward methylene blue (MB) degradation. In particular, Sn 0.05 ZnO shows excellent performance among the doped samples. The degradation rate of MB by Sn 0.05 ZnO reaches 99.61% after 120 min of illumination, which is approximately 2.2 times as high as that by undoped ZnO (45.88%). A comparison of the photocatalytic activity of the samples reveals the effects of Fe 3þ and Sn 4þ doping on the photocatalytic performance of ZnO on the basis of the following aspects: formation of impurity level, particle size, and pore structure of catalyst, microstructural changes in the crystal, and action of doped ions.

Facile fabrication of ternary MWCNTs/ZnO/Chitosan nanocomposite for enhanced photocatalytic degradation of methylene blue and antibacterial activity

“…8 , edge, valence band (VB), conduction band (CB) and the edge potential of Chitosan and ZnO semiconductor were measured by applying the following equations: where E CB represent the conduction band edge potential, E VB stand for the valence band edge potential, X is the electronegativity of the semiconductor, E g shows the bandgap of the semiconductor and E e stands for the energy of free electrons on the hydrogen scale which is about 4.5 eV vs. NHE 50 . The electronegativity of ZnO had been reported 5.47 eV 51 . The E VB and E CB of ZnO were measured to be 2.615 eV and − 0.135 eV, respectively.…”

Efficient Ni and Fe doping process in ZnO with enhanced photocatalytic activity: A theoretical and experimental investigation

“…The incorporation of dopants significantly changes the band gap of ZnO as a result of the appearance of intermediate energy levels within the forbidden region [17]. Additionally, this process can affect the crystalline structure, surface area, crystallite size and morphology of this oxide, as well as its physical and chemical properties [18][19][20][21][22][23]. In order to increase its technological applications, such characteristics can be tuned by choosing appropriate dopants and their concentration [24][25][26].…”

“…Recently, the incorporation of metallic ions such as Co 2+ [27,28], Ni 2+ [29,30], Fe 3+ [30] and Sn 4+ [20], into the ZnO structure to tune its properties, including its photocatalytic visible-light response, has also been investigated. Ji et al [20] showed that the degradation rate of methylene blue by Sn 0.05 ZnO reached 99.61% after 120 min of illumination, which was approximately 2.2 times higher than undoped ZnO.…”

“…Recently, the incorporation of metallic ions such as Co 2+ [27,28], Ni 2+ [29,30], Fe 3+ [30] and Sn 4+ [20], into the ZnO structure to tune its properties, including its photocatalytic visible-light response, has also been investigated. Ji et al [20] showed that the degradation rate of methylene blue by Sn 0.05 ZnO reached 99.61% after 120 min of illumination, which was approximately 2.2 times higher than undoped ZnO. Neena et al [31] synthesized g-C 3 N 4 -coupled Fe-doped ZnO micro-flowers and observed enhanced photocatalytic performance in the photo-degradation of the 2,4-dichlorophenol pollutant as a result of simultaneous Fe doping and coupling with g-C 3 N 4 .…”

One Pot Synthesis of Ternary MWCNTs/ZnO/Chitosan Nanocomposite for Enhanced Photocatalytic Degradation of Organic Dyes and Antibacterial Activity

“…E CB = E VB -E g (5) Where E CB represent the conduction band edge potential, E VB stand for the valence band edge potential, X is the electronegativity of the semiconductor, E g shows the bandgap of the semiconductor and E e stands for the energy of free electrons on the hydrogen scale which is about 4.5 eV vs. NHE 38 . The electronegativity of ZnO had been reported 5.47 eV 39 . The E VB and E CB of ZnO were measured to be 2.615 eV and − 0.135 eV, respectively.…”