Microstructural characterization and modified spectral response of cobalt doped NiO nanoparticles

The influence of cobalt doping in SnO 2 crystal lattice tailored the optical, structural, and surface properties of SnO 2 . Co 2+ was successfully doped in SnO 2 (Co-SnO 2 ) via green synthesis using Tradescantia spathacea aqueous leaf extract. Powder X-ray diffraction patterns of the synthesized nanoparticles showed a rutile structure with no impurities. As Co-doping was increased, the average crystallite size increased from 13.25 nm to 32.32 nm and BET results showed reduced surface area. The presence of organic compounds of the aqueous leaf extract was confirmed by Fourier-transform infrared spectroscopy. UV-visible diffuse reflectance spectroscopy showed a red shift suggesting a band gap reduction with Co-doping. The photoluminescence study showed a peak quenching with the increase in Co-doping. Spherical and smaller particles were observed by scanning electron microscopy. The density of states was proposed using X-ray photoelectron spectroscopy and UV-visible diffuse reflectance spectroscopy data. A novel antioxidant study of SnO 2 and Co-SnO 2 nanoparticles was done under visible light irradiation using 2,2-diphenyl-1-picrylhydrazyl free radicals and was compared to conventional antioxidant method in the dark. Photocatalytic 4nitrophenol conversion was also conducted in the dark and under visible light irradiation. The enhancement in the photoantioxidant activities and photocatalytic conversion of 4-nitrophenol to 4-nitrophenolate using SnO 2 and Co-SnO 2 was observed under visible light irradiation.Keywords SnO 2 . Tin(IV) oxide . Co-doped SnO 2 . Aqueous leaf extract . Tradescantia spathacea . Radical scavenging activity . 4-Nitrophenol

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“…The average lattice strain was reduced with Co-doping. This shows an agreement with the crystalline nature of SnO 2 with doping [56].…”

Section: X-ray Diffraction Analysis Of S-sno 2 and Co-sno 2 Npssupporting

confidence: 86%

Green and Phytogenic Fabrication of Co-Doped SnO2 Using Aqueous Leaf Extract of Tradescantia spathacea for Photoantioxidant and Photocatalytic Studies

et al. 2021

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“…Moreover, it is related to the structural modifications of NiO upon doping. Previous studies have also reported a decrease in the optical bandgap of NiO upon doping. − …”

Section: Resultsmentioning

confidence: 89%

Nanometer-Thick Mn:NiO and Co:NiO Films for High Performance Nonenzymatic Biosensors

Tutel

Koylan

Tunca

et al. 2021

ACS Appl. Nano Mater.

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People with diabetes require regular blood sugar level monitoring, using commercial enzyme-based biosensors. There is a considerable need to develop biosensors with nonenzymatic electrodes to eliminate the drawbacks of enzymes. Nanostructured nickel oxide (NiO) thin films are highly promising materials for the development of nonenzymatic glucose and hydrogen peroxide (H 2 O 2 ) biosensors. Although the biosensor performance can be easily attained with nonenzymatic electrodes, their commercialization still requires development of cost-effective and mass-production methods. In this work, we demonstrate the use of ultrasonic spray deposited, nanometer-thick, manganese and cobalt doped NiO (Mn:NiO and Co:NiO) films on indium tin oxide (ITO) coated glass substrates for glucose sensing. Sensor characterization followed detailed materials characterization. Nanometer-thick Co:NiO film electrodes showed better glucose sensor performance than those of bare NiO and Mn:NiO electrodes. High sensitivity of 1.67 μA/μM•cm 2 , a low detection limit of 231 nM, and a fast response time of 5.4 s within the linear range of 16−308 μM were obtained from nanometer-thick Co:NiO film electrodes. Amperometric measurements showed significant electrode reproducibility and stability. Nanometer-thick Co:NiO film electrode was also used to demonstrate actual clinical glucose measurements using human blood serum as a glucose source. Moreover, all fabricated nanometer-thick film electrodes were also utilized as H 2 O 2 sensors. This work provides a novel approach for monitoring the biosensor performance using nanometer-thick doped NiO film electrodes. Obtained results demonstrated the potential of ultrasonic spray deposition method for the massproduction of high-performance nonenzymatic nanometer-thick film biosensors.

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“…The UV absorbance peak is attributed to the direct recombination of electrons with holes in the valence band. However, the visible absorbance accounts for excess oxygen in the samples, which was also detectable by the EDX ratios [37]. Also, it could be related to the change in the oxidation state of copper, as obtained from the XPS spectra (Cu 1+ and Cu 2+ ) [37].…”

Section: Ultraviolet-visiblementioning

confidence: 96%

“…However, the visible absorbance accounts for excess oxygen in the samples, which was also detectable by the EDX ratios [37]. Also, it could be related to the change in the oxidation state of copper, as obtained from the XPS spectra (Cu 1+ and Cu 2+ ) [37]. Tauc's relation was used to calculate the optical band gap energy E g of Cu 1-x Mg x O nanoparticles [38], as shown by the following equation:…”

Section: Ultraviolet-visiblementioning

confidence: 99%

Impact of Mg-doping on the structural, optical, and magnetic properties of CuO nanoparticles and their antibiofilm activity

et al. 2023

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Doping in metal oxide systems is being chased by many researchers since it is enhancing their properties. In the present study, Cu1-xMgxO nanoparticles, capped with EDTA were synthesized by the chemical co-precipitation method, with x = 0.000, 0.005, 0.010, 0.015, and 0.020, and further characterized by different techniques. The impact of doping by Mg2+ ions on the structural, optical, and magnetic properties of CuO nanoparticles was investigated and the antibacterial activity of the synthesized nanoparticles was studied by antibiofilm screening. The X-ray Powder Diffraction (XRD) patterns show the formation of a pure CuO phase with a good incorporation of Mg-dopant into the CuO lattice due to the comparable ionic radii of Cu2+ and Mg2+ ions. The Mg-dopant increases the crystallite size from 25 nm (at x = 0.000) to 28.12 nm (at x = 0.020). The Transmission Electron Microscope (TEM) images reveal the effect of Mg-doping on the morphology of CuO nanoparticles by decreasing their agglomeration, resulting in more uniform spherical-shaped nanoparticles. Energy Dispersive X-ray (EDX) and X-ray Photoelectron Spectroscopy (XPS) confirm the purity and the successful development of Mg-doped CuO nanoparticles. The changes in the characteristic vibrational modes of CuO are studied by Raman spectra, upon Mg-doping. Furthermore, the optical properties explored by Ultraviolet-Visible (UV-Vis) spectroscopy reveal a redshift of the absorption peaks of CuO nanoparticles due to the Mg-doping. The energy gap (Eg) is affected by Mg-doping, where its broadening is attributed to the quantum confinement effect in CuO. The magnetic properties were investigated by Vibrating Sample Magnetometer (VSM) at room temperature. Cu1-xMgxO nanoparticles have combined paramagnetic and weak ferromagnetic behaviors. Besides, Cu1-xMgxO nanoparticles exhibited significant antibiofilm effects. These results highlight the potential use of Mg-doped CuO nanoparticles as antibiofilm agents.

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Microstructural characterization and modified spectral response of cobalt doped NiO nanoparticles

Cited by 50 publications

References 41 publications

Green and Phytogenic Fabrication of Co-Doped SnO2 Using Aqueous Leaf Extract of Tradescantia spathacea for Photoantioxidant and Photocatalytic Studies

Green and Phytogenic Fabrication of Co-Doped SnO2 Using Aqueous Leaf Extract of Tradescantia spathacea for Photoantioxidant and Photocatalytic Studies

Nanometer-Thick Mn:NiO and Co:NiO Films for High Performance Nonenzymatic Biosensors

Impact of Mg-doping on the structural, optical, and magnetic properties of CuO nanoparticles and their antibiofilm activity

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