Synthesis, characterisation and optical band gap of Cr_1.3Fe_0.7O₃ nanopigments

Abstract

Purpose -Inorganic pigments have been widely investigated due to their chemical stability such as resistance to chemical attacks by acids and alkalis, excellent hardness and high temperature stability. Cr 1.3 Fe 0.7 O 3 which is considered as a ceramic nanopigment also seems to be a highly efficient photovoltaic material. The paper aims to discuss these issues. Design/methodology/approach -In this work, the paper reports the synthesis of a novel and high purity Cr 1.3 Fe 0.7 O 3 nanopigment via sol-gel process using stearic acid as complexing agent. The method includes formation of an organic precursor with metallic cations homogeneously distributed all over the matrix. Sample characterisations were performed by X-ray diffraction, electron microscopy, UV-vis diffused reflectance spectra and photoluminescence. The transport properties and colour characteristics were also investigated by spectroscopic and technological characterisation of the synthesised nanoparticles. Findings -The prepared nanopigments were uniform in distribution and a spherical morphology with an average size of about 200 nm was observed. Cr 1.3 Fe 0.7 O 3 nanoparticles showed a direct band gap value of 2.85 eV and the colour efficiency of the nanopigments evaluated by colourimetric analysis resulted characteristic values of L * ¼ 39.96, a * ¼ 3.67 and b * ¼ 3.12. Originality/value -This method for synthesis of nanopigments is novel and could be employed for various applications in synthesis of wide variety of nanoceramics.

Synthesis, characterization and optical band gap of Pirochromite (MgCr2O4) Nanoparticles by Stearic Acid Sol-Gel Method

“…For its many applications, the nanosized spinel particles are greatly desired because nanocrystalline MgCr2O4 spinel particles certainly offer higher sintering reactivity, consequently decrease the sintering temperature of the product, and improve the properties of the products. The spinel structure includes a large family of compounds that exhibit a wide variety of physicochemical properties with important practical applications 2 . Thus, spinel oxides (AB2O4), pirochromite (MgCr2O4), and other related binary oxides have important technological applications, including their use as magnetic materials, high-temperature ceramics 3 , strengthening agents, sensor elements, interconnecting materials for solid oxide fuel cells, combustion catalysts, or catalytic supports [4][5][6][7][8] .…”

Modified Sol-Gel Processing of NiCr2O4 Nanoparticles; Structural Analysis and Optical Band Gap

“…An appropriate amount of stearic acid was first melted in a beaker at~346 K. A fixed amount of nickel acetate and ammonium dichromate dissolved in deionized water and added to the melted stearic acid. The heating process of this dual phase materials was continued for complete diffusing metallic-cations from aqueous to organic phase [27], naturally cooling down to room temperature followed by drying in oven to obtain dried gel denoted as precursor. The precursor was finally calcined at 1,073 K for 4 h in air.…”

An Outlook into the Magnetic and Magnetocaloric Properties of Cr1.3Fe0.7O3

“…[2] Interestingly, in the recent times, Cr 1.3 Fe 0.7 O 3 oxide is found to play a major role in the fields of photocatalytic hydrogen evolution, nano pigments, and catalysts and as a sensor to detect C 2 H 4 . [3][4][5][6] Cr 1.3 Fe 0.7 O 3 can be treated as a mixture of Fe 2 O 3 and Cr 2 O 3 , that is, (Cr 1-…”

“…[ 2 ] Interestingly, in the recent times, Cr 1.3 Fe 0.7 O 3 oxide is found to play a major role in the fields of photocatalytic hydrogen evolution, nano pigments, and catalysts and as a sensor to detect C 2 H 4 . [ 3–6 ] Cr 1.3 Fe 0.7 O 3 can be treated as a mixture of Fe 2 O 3 and Cr 2 O 3 , that is, (Cr 1– x Fe x ) 2 O 3 , x = 0.35. Fatemeh Paborji et al [ 7 ] proposed that the high‐temperature oxidation of FeCr 2 O 4 spinel results in Cr 1.3 Fe 0.7 O 3 phase.…”