Augmenting the photocatalytic performance of cobalt ferrite via change in structural and optical properties with the introduction of different rare earth metal ions. Issue 3 (15th February 2019)

• Record Type: Journal Article
• Authors: Dhiman, Manisha; Chudasama, Bhupendra; Kumar, Vinod; Tikoo, K.B.; Singhal, Sonal
• Is Part Of: Ceramics international. Volume 45:Issue 3(2019)
• Page Start: 3698
• Page End: 3709
• Publication Date: 2019-02-15
• Subjects: Rare earth substitution -- Magnetic nanoferrites -- Sol-gel method -- Structural and physical properties -- Photocatalysis; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.11.033
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In the present study, synthesis of different rare earth (RE) doped cobalt ferrite nanoparticles was done via facile sol-gel auto-combustion method using four different RE metal ions: Eu, Gd, Dy and Nd. The RE substituted cobalt ferrite nanoparticles were then characterized using FT-IR, powder XRD, HR-TEM, SAED, EDX, VSM and DRS techniques. From the characterization results, a significant variation in the structural, magnetic and optical properties of pure cobalt ferrite was observed with the introduction of different RE metal ions. This change in the properties was emerged due to the distortion of the ferrite crystal lattice due to replacement of smaller ionic radii Fe 3+ ions with the comparatively larger ionic radii RE 3+ metal ions. The catalytic activity of the fabricated RE doped cobalt ferrite nanoparticles was studied for the photo-Fenton degradation of cationic and anionic dyes. Under visible light irradiation, the as prepared RE doped nanoparticles exhibited great enhancement in the photo-Fenton degradation of dye molecules as compared to pure cobalt ferrite nanoparticles. The enhancement in the degradation rate was ascribed to the generation of defects in the crystal lattice, lower crystallite size and reduced band gap energy values which facilitated the facile transfer of photo-generated holes and electrons. Best catalytic results were obtained for CoNd0.08 Fe1.92 O4 for SO dye (k = 2.23 × 10 −1 min −1 ) which were found to be around 9 times higher than the pure cobalt ferrite nanoparticles (k = 0.23 × 10 −1 min −1 ). Graphical abstract: The introduction of RE metal ions resulted in the overall enhancement in the photocatalytic performance of ferrite molecules owing to octahedral site preference, lattice distortion, change in grain size and decreased band gap energy values of pristine CoFe2 O4 . fx1 Highlights: Different RE substituted CoREx Fe2-x O4 nanoparticles were synthesized using sol-gel route. Magnetically separable catalysts with narrow band gaps and lesser grain size were obtained. Effect of RE metal ions substitution on photocatalytic activity was studied. Role of active radical species involved in the degradation mechanism was examined.