Modification of energy level diagram of nano-crystalline ZnO by its composites with ZnWO4 suitable for sunlight assisted photo catalytic activity

Kale, Vaishali; Hunge, Y.M.; Kamble, Shalaka A.; Deshmukh, Madhuri; Bhoraskar, S. V.; Mathe, V. L.

doi:10.1016/j.mtcomm.2021.102101

Cited by 22 publications

(9 citation statements)

References 27 publications

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“…The best photocatalytic degradation activity was observed for the sample with 1/0.08 molar ratio calcined at 850 ºC, reaching 96% of RhB degradation under UV irradiation in 60 min. Hao et al [73] and according to other authors [74,75], calculated the valence band (VB) and conduction band (CB) potentials and reported that the CB band edge of ZnO is higher than that observed for ZnWO 4 . Therefore, the photogenerated electrons easily transfer from the CB of ZnO to that of ZnWO 4 through the heterostructure interface, while the photoinduced holes move from the VB of ZnWO 4 to that of ZnO.…”

Section: Zinc Tungstate-based Heterojunctionsmentioning

confidence: 99%

Zinc tungstate: a review on its application as heterogeneous photocatalyst

2022

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ZnWO 4 crystallizes in a monoclinic wolframite-like structure, which has been studied for applications in heterogeneous photocatalysis for degradation, oxidation, and reduction of various contaminants. This type of tungstate has proved to be an efficient photocatalyst under both ultraviolet and visible light irradiation and, when ZnWO 4 forms a heterostructure with other semiconductors or when it is doped with different ions, it has a great efficiency under sunlight irradiation. For instance, the optimization of ZnWO 4 efficiency has been attained by its heterojunction with different semiconductors such as ZnO, one of the most used materials for this purpose, but also with other compounds such as BiOBr, FeWO 4 , TiO 2 , WO 3 , Bi 2 WO 6 , among others. In addition, doping ZnWO 4 with the Ti 4+ , Bi 3+ , Ce 3+ , and Co 2+ metal ions or with nonmetals (Fand N 3-) can also increase the photocatalytic yield of the material. The photocatalytic properties of ZnWO 4 -based catalysts have been explored toward inorganic and organic molecules. However, among the variety of target molecules, organic pollutants such as methylene blue, methyl orange, and rhodamine B dyes appear as the most investigated in studies involving photocatalysis in the presence of ZnWO 4 . In our review, we summarize important literature works, highlighting the advancement in photocatalysis using ZnWO 4 .

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Section: Zinc Tungstate-based Heterojunctionsmentioning

confidence: 99%

Zinc tungstate: a review on its application as heterogeneous photocatalyst

2022

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“…High band gap energy of ZnO make ther are not applied in visible light. [16] Therefore, it is necessary to modify ZnO so that it can be applied to visible light. Modification is done by doped with metal ions.…”

Section: ][15]mentioning

confidence: 99%

Prototype of Hexagonal Photo-Reactor for Degradation Humic Acid Using Cu-Zno as a Catalyst in Visible Lights

Hawari¹,

Safitri²,

Anjali³

et al. 2022

ELECTROLYTE

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Humic acid is a heterogeneous organic compound that is carcinogenic in peat water and is very difficult to degrade biologically. Water is a source of life, therefore the need for clean water is increasing. This study aims to carry out the degradation of humic acid using the photocatalytic method. Photocatalysis is the degradation of humic acid using light in the presence of a photocatalyst in the reaction process. The photocatalyst used in this study was 7% Cu doped ZnO. The Cu doped ZnO used with a band gap of 2.57 eV and a particle size of 27 nm. In this study, the humic acid degradation process used a hexagonal photo reactor with various stirring speeds of 500, 1000, 1500 rpm and without stirring. The degradation process is carried out using outdoor light (direct sun). The light intensity can be measured using lightmeters on the front and rear of the reactor. The degradation process uses variations in irradiation time of 1, 2, 3, 4 and 5 hours. The degradation results were measured using a UV-Vis spectrophotometer to see the absorbance before and before degradation. The results of this study obtained the highest percentage degradation at the speed of each stirring of 500 rpm of 90.09% at 5 hours of irradiation, 1000 rpm of 97.37% at 5 hours of irradiation, 1500 rpm of 97.79% at 5 hours of irradiation. hours and without stirring of 71.71% at 5 hours of irradiation. The maximum degradation concentration in this study was obtained at a stirring speed of 1500 rpm and an irradiation time of 5 hours. The speed and irradiation time have an influence on the degradation results obtained.

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“…Various approaches to synthesize metal oxides such as TiO 2 (sol–gel technique, nanoparticles with a spherical morphology), CeO 2 (coprecipitation technique, QDs), ZnO (chemical precipitation method, nanorods), SnO 2 (hydrothermal method, spherical-shaped nanoparticles), etc. are used for reduction of the MB dye . Among these, hydrothermally synthesized SnO 2 QDs have attracted a significant deal of research interest in view of the exceptional optical and electrical characteristics such as low resistive power, large specific capacity, and appropriate Eg (3.6 eV).…”

Section: Introductionmentioning

confidence: 99%

“…are used for reduction of the MB dye. 16 Among these, hydrothermally synthesized SnO 2 QDs have attracted a significant deal of research interest in view of the exceptional optical and electrical characteristics such as low resistive power, large specific capacity, and appropriate Eg (3.6 eV). Moreover, SnO 2 QDs have large electron flexibility (∼100 to 200 cm 2 V –1 s –1 ), revealing a rapid transfer of photoexcited electrons.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Sonophotocatalytic, Photocatalytic, and Catalytic Activities of Magnesium and Chitosan-Doped Tin Oxide Quantum Dots

et al. 2022

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The present study demonstrates the hydrothermal synthesis of SnO2 quantum dots (QDs) doped with different concentrations (2, 4 wt %) of magnesium (Mg) and a fixed amount of chitosan (CS). The obtained samples were investigated through a number of characterizations for optical analysis, elemental composition, crystal structure, functional group presence, interlayer spacing, and surface morphology. The XRD spectrum revealed the tetragonal structure of SnO2 with no significant variations occurring upon the addition of CS and Mg. The crystallite size of QDs was reduced by incorporation of dopants. The optical absorption spectra revealed a red shift, assigned to the reduction of the band gap energy upon doping. TEM analysis proved that the few nanorod-like structures of CS overlapped with SnO2 QDs, and agglomeration was observed upon Mg doping. The incorporation of dopants little enhanced the d-spacing of SnO2 QDs. Moreover, the synthesized nanocatalyst was utilized to calculate the degradation percentage of methylene blue (MB) dye. Afterward, a comparative analysis of catalytic activity, photocatalytic activity, and sonophotocatalytic activity was carried out. Notably, 4% Mg/CS-doped QDs showed maximum sonophotocatalytic degradation of MB in basic medium compared to other activities. Lastly, the prepared nanocatalyst was found to be efficient for dye degradation in any environment and inexpensive.

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Modification of energy level diagram of nano-crystalline ZnO by its composites with ZnWO4 suitable for sunlight assisted photo catalytic activity

Cited by 22 publications

References 27 publications

Zinc tungstate: a review on its application as heterogeneous photocatalyst

Zinc tungstate: a review on its application as heterogeneous photocatalyst

Prototype of Hexagonal Photo-Reactor for Degradation Humic Acid Using Cu-Zno as a Catalyst in Visible Lights

Comparative Study of Sonophotocatalytic, Photocatalytic, and Catalytic Activities of Magnesium and Chitosan-Doped Tin Oxide Quantum Dots

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