Structure, optical properties and antimicrobial activities of MgO–Bi2−xCrxO3 nanocomposites prepared via solvent-deficient method

Abstract

MgO–Bi2−xCrxO3 nanocomposites for x = 0 and 0.07 were fabricated using the solvent-deficient route. X-ray diffraction method, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA) and UV–Vis spectroscopy were employed to study the properties. The samples were also evaluated for the antibacterial activity. The x = 0 sample showed a dominant monoclinic crystalline structure of $$\alpha\text{-}{\text{Bi}}_{2}{\text{O}}_{3}$$ α -Bi 2 O 3 phase. No peaks attributed to MgO were observed. Cr-doped $$\text{MgO}{-}{\text{Bi}}_{2}{\text{O}}_{3}$$ MgO - Bi 2 O 3 in which Bi was substituted showed that $${\text{the tetragonal BiCrO}}_{3}$$ the tetragonal BiCrO 3 phase was also present in the $$\text{MgO}{-}{\text{Bi}}_{2}{\text{O}}_{3}$$ MgO - Bi 2 O 3 composite. The Scherrer formula was employed to determine the crystallite size of the samples. The Cr-doped sample showed a decrease in the crystallite size. The microstructures of the non-doped MgO–Bi2O3 and MgO–Bi1.93Cr0.07O3 composites consisted of micrometer sized grains and were uniformly distributed. Direct transition energy gap, $${E}_{\text{g}}$$ E g decreased from 3.14 to 2.77 eV with Cr-doping as determined from UV–Vis spectroscopy. The Cr-doped $$\text{MgO}{-}{\text{Bi}}_{2}{\text{O}}_{3}$$ MgO - Bi 2 O 3 nanocomposites exhibited two energy gaps at 2.36 and 2.76 eV. The antibacterial activity was determined against gram-negative bacteria (Salmonella typhimurium and Pseudomonas aeruginosa) and gram-positive bacteria (Staphylococcus aureus) by disc diffusion method. Cr-doping led to a decrease in inhibitory activity of MgO–Bi2−xCrxO3 nanocomposite against the various types of bacteria.

Synthesis of glycine-mediated CuO–Fe2O3–MgO nanocomposites: Structural, optical, and antibacterial properties

“…The diffraction peaks were matched with JCPDS files of CuO (74-1021), Fe 2 O 3 (76-1821), MgO (45-0946), and CuFe 2 O 4 (72-1174) with monoclinic, hexagonal, cubic, and tetragonal crystals, respectively, indicating the polycrystalline nature of the synthesized materials. The average crystallite size (D, nm) of G1, G1.5, and G2 samples were computed by Scherrer's law and Bragg's law as expressed by equations ( 1) and (2) 45,46 nλ ¼ 2dsinθ…”

“…The diffraction peaks were matched with JCPDS files of CuO (74–1021), Fe 2 O 3 (76–1821), MgO (45–0946), and CuFe 2 O 4 (72–1174) with monoclinic, hexagonal, cubic, and tetragonal crystals, respectively, indicating the polycrystalline nature of the synthesized materials. The average crystallite size (D, nm) of G1, G1.5, and G2 samples were computed by Scherrer’s law and Bragg’s law as expressed by equations (1) and (2) 45,46 where D is the size of crystalline domain, λ (0.154 nm) is the incident radiation wavelength, θ is the diffraction angle, 𝛽 is the full–width at half maximum, d-spacing Å is the inter-atomic spacing, and n is the order of reflection. The dislocation density ( δ ) was evaluated by the relation given in equation (3).…”

Synthesis of trimetallic oxide (Fe2O3–MgO–CuO) nanocomposites and evaluation of their structural and optical properties

“…1 . The cell volume (v), lattice constants (a, b, c) and d-spacing for pure CuO monoclinic, MgO cubic and Fe 2 O 3 hexagonal phase and Fe 2 O 3 –MgO–CuO nanocomposite were calculated 22 , 33 – 36 and listed in Table 1 .

Figure 1 XRD patterns of CuO, Fe 2 O 3 , MgO and Fe 2 O 3 –MgO–CuO nanocomposites.

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“…Furthermore, it is a non-toxic and readily available semiconductor 18 , 19 . Magnesium oxide (MgO), with a direct bandgap of 5.2–7 eV, is an n-type semiconductor that displays noticeable structural, catalytic, optical, and chemical properties 17 , 20 – 22 . Iron(III) oxide (Fe 2 O 3 ) is a narrow bandgap of nearly 2 eV.…”

Garlic Extract-Mediated Synthesis of ZnS Nanoparticles: Structural, Optical, Antibacterial, and Hemolysis Studies

“…Plant-based biosynthesis of NPs basically involves the application of plant extracts to reduce and stabilize metal ions through some implicated plant phytocompounds like amino acids, alkaloids, enzymes, saponins, terpenoids, phenolics [4,5], etc. ZnS is a promising semiconductor with a wide bandgap, which benefiting electronic, optoelectronic, and electrochemical devices [6].…”