Preparation and Characterization of Zn1-xNixFe2O4 Nanoparticles with Spinel Structure Synthesized by Hydrothermal Method

Optical properties of Cr doped ZnAl2O4 nanoparticles with Spinel structure synthesized by hydrothermal method

“…In addition, with the increase of Cr concentration, the intensity of FT-IR spectra for Zn 1−x Cr x Al 2 O 4 samples decreases slowly in the range of 400-700 cm −1 region, and the peaks moving toward long wavelength direction and occurs red shift. This is mainly due to the cation distribution in ZnAl 2 O 4 nanocrystals changes significantly when Cr ions entered ZnAl 2 O 4 lattice and replaced Zn ions and the particle size reaches the nanoscale scale, some Al 3+ enters the A position of tetrahedron, and Cr 3+ enters the B position of octahedron, which leads to the generation of ion logarithm of super exchange between A and B [10], and introduce new interstitial structural defects in spinel structure, the new introduced structural defects will lead to redshift of the spectra, which is consistent with the UV-vis analysis results. Figure 9 shows PL spectra of Zn 1−x Cr x Al 2 O 4 (x=0, 0.01, 0.03, 0.05 and 0.07) samples with excitation wavelength of 300 nm at room temperature.…”

“…Spinel structure metal-oxide (AB 2 O 4 ) is a kind of important functional semiconductor materials, which have attracted extensive attention due to its unique crystal structure, special properties and broad application prospect in the fields, such as catalysts, catalytic carriers, high-temperature ceramics, optical materials, sensors and dielectric materials [1][2][3][4][5][6][7], etc. In the formula AB 2 O 4 , A represents the tetrahedral position occupied by bivalent metal cations, and the tetrahedral gap formed by four oxygen ions, while B position represents the octahedral position occupied by the trivalent metal cations, and the octahedral void formed by six oxygen ions [8][9][10]. According to the metal cation distribution, the general chemical formula of spinel structure can be written as (A 1−x B x )[A x B 2-x ]O 4 , where ()represents tetrahedral position, [] represents octahedral position, and x is the inversion coefficient.…”

Magnetically Recoverable Cr and Mn Co-Doped Zn0.95−xCr0.05MnxAl2O4 Nanoparticles for Dye Degradation Under Simulated Sunlight Irradiation

“…[26][27][28][29] The crystal structure and band structure of a spinel structure metal oxide can be adjusted by doping with a transition metal ion, which can extend the visible light response region, inhibit the recombination of photoinduced electron-hole pairs, enhance the photocatalytic activity, increase the separation rate of photoinduced carriers and improve photocatalytic activity. 30,31 In addition, transition metal ion-doped ZnAl 2 O 4 exhibits roomtemperature ferromagnetism, which can be effectively separated and recovered by an external magnetic field. 22 The hole or electron carrier acts as the receptor or donor, and the electrical, magnetic and optical properties of the new semiconductor materials are controlled by adjusting the carrier type and concentration.…”