Nickel aluminate (NiAl2O4) and doped nickel aluminate (Ni1-xMxAl2O4; M = Mg, Zn, Cu; x = 0.1) were prepared by sol-gel method using citric acid. The synthesized compounds were analyzed by various techniques such as powder XRD, FTIR, SEM-EDAX and UV-DRS. The lattice parameter was found to increase with the copper, zinc and magnesium doping in nickel aluminate. The band gap was decreased from 3.0 eV (NiAl2O4) to 2.9 (zinc doped), 2.7 eV (magnesium doped) and increased to 3.1 eV in the case of copper doping. The catalytic study was carried out for a cationic (methylene blue) and an anionic dye (methyl orange). The percentage degradation of methyl orange using Zn0.1Ni0.9Al2O4 and Mg0.1Ni0.9Al2O4 was found to be 92% (180 min) and 96% (90 min). 93% (120 min) and 97% (120 min) degradation of methylene blue was observed using zinc doped and magnesium doped nickel aluminate respectively. These results are comparatively higher than its parent analogue (94% (180 min) degradation against methyl orange and 91% (120 min) against methylene blue). Whereas the percentage degradation was found to be less in the case of Cu0.1Ni0.9Al2O4 (83% (180 min) against methyl orange and 90% (120 min) against methylene blue). © 2018 Elsevier Masson SAS

Elakkiya V

Department of Chemistry

School of Advanced Sciences

Vellore Campus

Sumathi S

Agarwal Y

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Solid State Sciences

In the current investigation, a new series of Ce doped gahnites of the formula ZnAl2-xCexO4 (x = 0–0.04), Fe doped gahnites of the formula ZnAl2-yFeyO4 (y = 0–0.5) and Ce and Fe co-doped gahnites of the formula ZnAl2-x-yCexFeyO4 (x = 0–0.04; y = 0–0.5) with high near infrared (NIR) reflectance were fabricated to mitigate the heat island effect. All the designed pigments were characterized by powder X-ray diffraction (PXRD), Fourier transformed infra red spectroscopy (FT-IR), Ultraviolet-Diffuse reflectance spectroscopy (UV-DRS). Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscopy (TEM) and CIE-L*a*b* colour values. Band gap of the white gahnite of the formula ZnAl2O4 (Eg = 3.8 eV) shifted to 2.70 eV and 2.15 eV for the pigments ZnAl1.96Ce0.04O4 and ZnAl1.5Fe0.5O4 respectively. Ce doped gahnites broadened the absorption centre from 250 nm to 350 nm in the UV spectrum and resulted in yellow colour. Whereas Fe doping introduced additional electronic transition between 440 nm and 490 nm and exhibited reddish yellow colour. NIR reflectance of ZnAl1.96Ce0.04O4, ZnAl1.5Fe0.5O4 and ZnAl1.78Fe0.2Ce0.02O4 was found to be 86%, 65%, 80% respectively between 700 and 2500 nm regions. Good thermal and chemical stability along with high NIR reflectance made the prepared pigments as a potential candidate to design cool roofing materials. © 2019 Elsevier B.V.

Journal of Alloys and Compounds

Ce and Fe doped gahnite: Cost effective solar reflective pigment for cool coating applications

Co1-xCuxFe2O4 nanoparticles with x = 0 and 0.5 were synthesized through the combustion method. The as-made materials are face centered-cubic close-packed spinel structures. The characterization techniques such as powder XRD, FTIR, UV-DRS and SEM studies collectively verified that the formed products are cobalt ferrite and copper substituted cobalt ferrite nanoparticles. In addition, the mean crystalline size, lattice parameter and band gap energy of nanoparticles are calculated. The photocatalytic activity of the obtained Co1-xCuxFe2O4 spinel nanoparticles is evaluated by monitoring the degradation of congo red under visible light irradiation. © Published under licence by IOP Publishing Ltd.

Fulltext

IOP Conference Series: Materials Science and Engineering

Photocatalytic degradation of congo red using copper substituted cobalt ferrite

In the current work, zinc aluminate and bismuth doped zinc aluminate (ZnAl2-xBixO4, x = 0, 0.05, 0.1) spinel oxide nanoparticles were synthesized by co-precipitation method. The obtained samples were characterized by powder XRD, FT-IR, DRS, SEM-EDX and BET. Photocatalytic degradation of zinc aluminate and bismuth doped zinc aluminate nanoparticles were investigated using methylene blue as a model pollutant under UV light. 98. 28% of photodegradation of methylene blue was achieved in 150 min using the bismuth doped zinc aluminate catalyst. The reduction of 4-nitrophenol to 4-aminophenol was completed within 7 s using bismuth doped catalyst. © 2017 Elsevier Ltd

Materials Research Bulletin

Catalytic activity of bismuth doped zinc aluminate nanoparticles towards environmental remediation

In this study, bismuth doped copper aluminate (CuAl2-xBixO4 x = 0, 0.01, 0.03, 0.05 and 0.10) nanoparticles were prepared via the solution combustion method and characterized by numerous procedures like powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, diffuse reflectance spectroscopy (DRS), scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDAX) and vibrating sample magnetometer (VSM). UV–Vis spectra exhibit low band gap energy ranging from 1.77 to 1.88 eV for the synthesized semiconductor oxide nanoparticles. The photocatalytic activity of copper aluminate and bismuth doped copper aluminate nanoparticles was studied by performing the decomposition of organic pollutants such as Methylene blue and Rhodamine-B under UV-light and visible light. It has been noticed from the results that the highest degradation was observed for Methylene blue dye with the bismuth doped copper aluminate (CAB03) nanoparticles compared to Rhodamine B. 99.71% degradation of Methylene blue was obtained within 60 min under UV-light irradiation and 99.90% within 60 min under visible light (H2O2) with 25 mg of catalyst. © 2017 Elsevier B.V.

Materials Chemistry and Physics

Structural, optical, magnetic and photocatalytic properties of bismuth doped copper aluminate nanoparticles

Zinc aluminate and cerium-doped zinc aluminate nanoparticles are synthesised by co-precipitation method. Ammonium hydroxide is used as a precipitating agent. The synthesised compounds are characterised by powder X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FT-IR), Ultraviolet diffuse reflectance spectroscopy (UV-DRS), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) and Surface area measurements. The photocatalytic activity of zinc aluminate and cerium doped zinc aluminate nanoparticles are studied under the UV light and visible light taking methylene blue as a model pollutant. The amount of catalyst, concentration of dye solution and time are optimised under UV-light. Degradation of methylene blue under the UV-light is found to be 99% in 20 min with 10 mg of cerium doped catalyst. Compared to visible light degradation, the degradation of dye under UV-light is higher. Cerium doping in zinc aluminate (ZnAl2O4:Ce3+) increased the photocatalytic activity of zinc aluminate. © 2017 Elsevier Masson SAS

Structural, optical and photocatalytic activity of cerium doped zinc aluminate

In the present work, synthesis of nickel aluminate using Opuntia dilenii haw as plant extract by a microwave combustion method (MCM) and its comparison with the conventional combustion method (CCM) is investigated. O. dilenii haw plant extract simplifies the process, provides an alternative process for a simple and an economical synthesis. The absence of surfactant has led to a simple, cheap and fast method of synthesis of NiAl2O4 nanoparticles. The as-synthesized NiAl2O4 nanoparticles were characterized by X-ray diffraction (XRD) studies, Fourier transform infrared spectroscopy (FT-IR) studies, high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), high resolution transmission electron microscopy (HR-TEM), diffuses reflectance spectroscopy (DRS), and Brunauer Emmett Teller (BET) surface area analysis. The XRD results confirmed the formation of the cubic phase NiAl2O4. The formation of pure nickel aluminate phase was confirmed by FT-IR. The formation of NiAl2O4 nanoparticles was confirmed by HR-SEM and HR-TEM and their possible formation mechanisms were also proposed. MCM could produce NiAl2O4 with uniform size and well-defined shape with crystallinity. The optical property was determined by DRS. NiAl2O4 prepared by the microwave combustion method was found to possess a higher surface area, lower crystallite size than the NiAl2O4 nanoparticles prepared by the conventional combustion method, which in turn has led to the improved performance toward the selective oxidation of benzyl alcohol to benzaldehyde. © 2014 King Saud University

Journal	Data powered by TypesetSolid State Sciences
Publisher	Data powered by TypesetElsevier BV
ISSN	1293-2558
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