Synthesis of Perovskite Phase Strontium Substituted Cerium Ferrites for its Photocatalytic Application

Abstract

Perovskites prepared in nanoscale have recently received extensive attention as the inorganic perovskite-type oxides are fascinating materials due to their wide range of applications as catalysts, solid-oxide fuel cells, sensors and so on. In the current study, sol-gel method was applied and the corresponding metal nitrates were used as precursors for the preparation of pure and mixed cerium strontium ferrites in perovskite phase. The materials were sintered at 800 o C for 8 hours to obtain in nanoscale. Substitution in A or B site of ABO 3 perovskite structure modifies the properties of the materials. The structural, optical and magnetic properties of the as synthesized materials were investigated using PXRD, FT-IR, UV-DRS, TEM and VSM techniques. The photo catalytic activity of the synthesized nano materials using the cationic methylene blue dye indicated higher degradation efficiency of about 97% for mixed ferrite compared to pure oxides. I. NTRODUCTION Perovskites are mixed metal oxides with the general formula ABO 3+/-δ where A is rare earth ion and B can be alkaline earth metal or transition metal ion. Partial substitution of A and B ions can lead to the formation of variety of compounds with general formula A 1-x A x B 1-Y B'YO 3+/-δ due to non-stoichiometry. Rare-earth ferrites have a tilted orthorhombic structure as the cation sites are highly substitutable which helps in modifying the properties such as: conductivity, pyroelectric, piezoelectric, magneto-optic, ferro-electric, magnetic for studying the specific applications of perovskite [1-10]. Several methods employed for nanomaterial synthesis include sol-gel, co-precipitation, solid-state sintering, and combustion route [11, 12]. Extensive modifications of the structural and magnetic properties were observed on substituting Sr 2+ and La 3+ in La 1-x Sr x FeO 3-δ in comparison with pure LaFeO 3 perovskite where there is no magnetic interaction between Fe 3+ and La 3+ as La 3+ is non-magnetic in nature [13]. Saeid Jabbarzare et.al reported on the synthesis of cerium ferrite perovskite and investigated for the magnetic, photocatalytic, absorption and dielectric properties which indicated CeFeO 3 as a ceramic with good colossal dielectric constant. SrFeO 3-δ was prepared by sol-gel route to study the conductivity and see back measurements. Shivendra Kumar Jaiswal et.al [14] synthesized via sol-gel route produced highly stable anion deficient strontium ferrite which acts as a filter for air with excellent oxygen permeation characteristics [15]. Therefore, an attempt has been made here to synthesize cerium strontium ferrite perovskite via sol-gel method. Further, in addition pure oxides, cerium strontium oxide and cerium ferrite were compared with the mixed novel ferrite by thoroughly analyzing the optical, structural and magnetic properties of the synthesized materials. II. EXPERIMENTAL DETAILS A. Synthesis of perovskite oxides For the synthesis of pure and mixed nano ferrites, appropriate amounts of cerous nitrate, strontium nitrate and ferric nitrate were used as precursors. Initially, citric acid was dissolved in ethylene glycol and was placed in magnetic stirrer at 150 o C for 15 minutes. The nitrate solutions on mixing with the above solution on continuous stirring gave rise to gel which was digested for 3 hours at 250 o C. The solid mass obtained was subsequently sintered in muffle furnace at 800 o C for 8 hours to produce fine powders as the final product.