Effect of Sr doping in ZnO microspheres for solar light-driven photodegradation of organic pollutants

Selvaraj, Saravanan; Palanivel, Baskaran; Simon, Patrick; Mohan, M. Krishna; Navaneethan, M.; Ponnusamy, S.; Muthamizhchelvan, C.

doi:10.1007/s10854-021-06875-6

Cited by 13 publications

(15 citation statements)

References 32 publications

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“…So, 10 mg of photocatalyst may be more efficient for separating photo induced electron-hole pairs and show enhanced photocatalytic activity because of small particle size. The improvement in the photocatalytic activity of Gd doped ZnO is due to the formation of Zn−O−Gd bonds formed on the surface of ZnO [26]. The reason for the high activity of the doped samples and the result of Gd loading on the PC property can be explained by the following mechanism.…”

Section: Resultsmentioning

confidence: 99%

“…During the photocatalytic process, the valence band electrons of ZnO crystal lattice are excited to reach the conduction band upon the exposure of light. The generation of hydroxyl radicals by the holes in the valence band leads to the degradation of MB as these radicals react with water [26]. Gd 2+ ions are created as the reaction of Gd 3+ ions take place with the electrons in the conduction band of ZnO.…”

Section: Resultsmentioning

confidence: 99%

“…Super oxide radicals are created when the Gd 2+ ions are diffused into the atmospheric oxygen and react with the water molecules to produce H 2 O 2 which further leads to the formation of hydroxyl radicals. The dye molecules are degraded upon interacting with these radicals [19,25,26]. The overall process leads to the trapping of electrons and the recombination of photo-induced charge carriers is vanquished.…”

Section: Resultsmentioning

confidence: 99%

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Growth and Gd doping of ZnO nanostructures with enhanced structural, optical properties and photocatalytic applications

Dash

Sahu

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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In this study, pure and Gadolinium doped ZnO (Gd-ZnO) nanoparticles have been synthesized by wet chemical method and the effect of Gadolinium incorporation on the structure and optical activity of ZnO was examined. The average size of the undoped ZnO and Gd-ZnO (0.002 M and 0.003 M) nanoparticles was found to be 48 nm, 44 nm and 42 nm respectively which shows the lattice compression of ZnO after Gd doping. TEM study shows the hexagonal nanocrystallites of Gd-ZnO with size around 45 nm is formed. FTIR study shows the metal-oxygen band below 600 cm−1 and absorbance study gives the information about the narrowing of band gap of ZnO after Gd doping. The photocatalytic degradation efficiency of Gd-ZnO (92 %) has been found to be better as compared to undoped ZnO (89 %) in degrading methyl blue (MB). The photodegradation of MB is found to follow first order kinetics.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Growth and Gd doping of ZnO nanostructures with enhanced structural, optical properties and photocatalytic applications

Dash

Sahu

2022

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Some changes in crystal lattice owing to defects or oxygen voids created in the ZnO crystal lattice are associated with the red‐shifted absorbance peak of GZO samples. [ 34 ]…”

Section: Resultsmentioning

confidence: 99%

Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd³⁺‐Substituted ZnO Nanoparticles

Sahu

Kumar

Vats

et al. 2022

Part & Part Syst Charact

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of ZnO has not yet been completely realized and explored despite two decades of rigorous research. It has a wide range of uses in photocatalysts, UV lasers, solar cells, photodiodes, sensors, optoelectronics, spintronic devices, and more. [1][2][3][4][5][6] Depending on the application, essential modifications have been made over time to increase the stability of ZnO nanostructures. High quantum confinement effect plays a significant role in the configuration of the electronic structure at the nanoscale. Also, factors such as doping, defects, and crystallinity affect various properties of the nanostructures. Doping ZnO with appropriate ions with varying sizes is great approach way to vary its properties for certain device applications. [7][8][9] According to Chaudhary et al., WO 3 -ZnO@rGO nanocomposites can be used for relevant photocatalytic applications and wastewater purification. [10] Additionally, Yousaf et al. have reported that the ZnO-NiO/rGO nanohybrid shows exceptional photocatalytic performance and is a reliable contender in the field of catalysis. [11] Transition metal (TM) and rare earth (RE)-doped metal oxides have been studied extensively under this regime. For optoelectronics and spintronic applications, ZnO doped with rare-earth ions is Undoped ZnO and Zn 1−x Gd x O nanoparticles are made using a sono-chemical co-precipitation approach. X-ray diffraction and transmission electron microscopy investigations verified the formation of a wurtzite structure with spherical geometry. All the samples are found to be nanocrystalline by transmission electron microscopy, with crystallite diameters ranging from 14 to 22 nm. The optical constants are calculated via diffuse reflectance spectroscopy. The Urbach energy and photoluminescence spectrum both showed that all doped nanoparticle samples contained defects and disorder due to vacancies. The band structure finding suggest that the forbidden gap of ZnO may change due to the conduction band shift, Burstein-Moss shift, and shrinkage effect. The near band emission in the ultraviolet region and deep level emission of the photoluminescence spectrum are both strong and decreased with increasing Gd 3+ concentration. Studies using X-ray absorption near edge spectroscopy revealed that the host nano-lattice Zn sites are substituted with Gd 3+ cations to preserve the symmetry with minor distortion. Investigations into charge transfer through the oxygen bands (Gd-O-Zn) are made using O K-edge spectra. The defect emission bands identified through Gd doping indicated that these emissions may be changed for ZnO samples, which could be advantageous for applications in phosphors and light-emitting devices.

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“…Photocatalysts have been proven to be the best candidates for the degradation of organic pollutants. Their performance can be further improved by introducing a metal which contributes to a delay of electron recombination holes as well as lowering the band gap to obtain a spontaneous photodegradation [12,16].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of eco-friendly ZnO-based heterophotocatalysts with enhanced properties under visible light

Mougnol

Waanders

Ntwampe

et al. 2022

Preprint

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Heterogeneous photocatalysts have been widely used for the removal of various organic pollutants from wastewater. The main challenge so far resides in the sustainability of the process, with regard to the synthesis and the application under visible light. In this study the precipitated materials from the moringa oleifera seed (MO), groundnut shells (GS) and apatite (A) agrowastes were functionalized with zinc oxide (ZnO) and silver (Ag) solution, to produce novel bioheterophotocatalysts. Various analytical techniques such as scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDS), photoluminescence (PL) and x-ray diffraction (XRD) analyses were used for the characterization of the novel photocatalysts. It was proven that, besides the addition of metals into a semiconductor, agrowastes were also proven to be even better to enhance the photocatalytic activity of a ZnO-based photocatalyst. The combination of MO/GS/A/ZnO/Ag in a 1:1:1 ratio, resulted in a lower band gap of 1.59 eV, as compared to the larger band gap of 2.96 eV for ZnO/ Ag. These photocatalysts' efficiency was also tested on the photodegradation of PAHs derived from coal leaching in various water sources such as acidic mine drainage, alkaline mine drainage and sewage wastewater. From MO/GS/A/ZnO/Ag, the removal efficiency was obtained to be 69.59%, 62.19% and 61.68% while 52.62%, 37.96 and 44.30% using ZnO/Ag in acidic mine drainage, alkaline mine drainage and sewage wastewater in 60 min under solar irradiation. Which happens to highly influence the destabilization of PAHs in the water sources.

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Effect of Sr doping in ZnO microspheres for solar light-driven photodegradation of organic pollutants

Cited by 13 publications

References 32 publications

Growth and Gd doping of ZnO nanostructures with enhanced structural, optical properties and photocatalytic applications

Growth and Gd doping of ZnO nanostructures with enhanced structural, optical properties and photocatalytic applications

Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd³⁺‐Substituted ZnO Nanoparticles

Synthesis of eco-friendly ZnO-based heterophotocatalysts with enhanced properties under visible light

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Effect of Sr doping in ZnO microspheres for solar light-driven photodegradation of organic pollutants

Cited by 13 publications

References 32 publications

Growth and Gd doping of ZnO nanostructures with enhanced structural, optical properties and photocatalytic applications

Growth and Gd doping of ZnO nanostructures with enhanced structural, optical properties and photocatalytic applications

Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd3+‐Substituted ZnO Nanoparticles

Synthesis of eco-friendly ZnO-based heterophotocatalysts with enhanced properties under visible light

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Exploring the Defects and Vacancies with Photoluminescence and XANES Studies of Gd³⁺‐Substituted ZnO Nanoparticles