Pechini synthesis and microstructure of nickel-doped copper chromites

Abstract

Spinel-type solid solutions were synthesized by the Pechini method and calcined between 500 and 900 °C for 4 hours and at 900 °C for 8 hours to produce ceramic pigments. The resulting powders were characterized by thermogravimetric analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), particle size analysis and BET surface area measurements. The formation of spinel took place upon calcination at 700 °C. IR spectroscopy revealed the presence of n1 and n2 bands, typical of spinel structures, broadened by the presence of more than one cationic species in the structure. The specific area of the resulting powder decreased from 24.7 to 1.4 m² g-1 as the calcination temperature increased from 700 to 900 °C. Microstructural analyses revealed the presence of crystalline spinel as the only phase present in powders calcined at 900 °C. Colorimetric analyses using L*a*b* coordinates and UV-visible spectroscopy revealed that the pigment was predominantly black

Effects of multi-dopants (Zn and Ho) in stabilizing spinel structure for cathode materials in lithium rechargeable batteries—Novel chelated sol–gel synthesis

“…The FTIR spectra of LiMn 2 O 4 synthesized via sol-gel and coprecipitation methods have been reported by several researchers (Thirunakaran et al, 2009;Iqbal & Ahmad, 2008;Khedar, Abousekkina, & El-Metwaly, 2013). The IR spectroscopic bands of the sample calcined at 850 • C observed at 510-520 and 610-618 cm −1 are ascribed to Li O bending vibrations and Li Mn O stretching vibrations, which are in good agreement with earlier studies (Pimentel et al, 2005). The bands for the samples calcined at 250, 450, 650, and 850 • C shifted slightly to lower wave numbers.…”

Cerium and zinc: Dual-doped LiMn2O4 spinels as cathode material for use in lithium rechargeable batteries

“…6. FT-IR studies on spinel LiMn 2 O 4 have been undertaken by Pimentel et al [30]. Details of the wave number corresponding to the LiMn 2 O 4 and LiZn x Ce y Mn 2−x−y O 4 spinels are given in Tables 2 and 3.…”

Applications and Preparation Methods of Copper Chromite Catalysts: A Review

“…The Pechini method [361,362] based on polymeric precursors, is used to prepare spinels and it does not require high temperature calcinations and permits good stoichiometric control as well as reproducibility. This method consists of the formation of a polymeric resin between a metallic acid chelate and polyhydroxide alcohol by polyesterification.…”