Mini-review: Ferrite nanoparticles in the catalysis

Abstract

Recent applications of ferrite nanoparticles as catalysts in organic processes are reviewed. Catalytic applications include the use of mainly cobalt, nickel, copper, and zinc ferrites, as well as their mixed-metal combinations with Cr, Cd, Mn and sometimes some lanthanides. Core-shell nanostructures with silica and titania are also used without loss of magnetic properties. The ferrite nanomaterials are obtained mainly by wet-chemical sol-gel or co-precipitation methods, more rarely by sonochemical technique, mechanical high-energy ball milling, spark plasma sintering, microwave heating or hydrothermal route. Catalytic processes with application of ferrite nanoparticles include decomposition (in particular photocatalytic), reactions of dehydrogenation, oxidation, alkylation, C-C coupling, among other processes. Ferrite nano catalysts can be easily recovered from reaction systems and reused up to several runs almost without loss of catalytic activity.

Magnetically Separable Transition Metal Ferrites: Versatile Heterogeneous Nano‐Catalysts for the Synthesis of Diverse Bioactive Heterocycles

“…[8,9] Transition metal based nanomaterials are playing dual role by mimicking metal surface activation as well as providing nano-sized support systems. [10,11] Among various magnetic nano-particles used as catalysts, transition metal ferrites (MFe 2 O 4 ) have drawn significant attention in both academia as well as industry due to their chemical stability, high saturation magnetization, high permeability, insolubility in most reaction solvents, low toxicity, readily accessibility, inexpensiveness, simply recoverable and reusability. [12,13] These spinel type cubic nano-ferrites with the general formula (M 2 + )(Fe 3 + ) 2 O 4 possess both Lewis acidic (due to Fe 3 + of Fe 2 O 3 ) as well as basic character (due to O 2À of MO, where M = Mn 2 + , Co 2 + , Ni 2 + , Cu 2 + and Zn 2 + ).…”

Synthesis and Catalytic Properties of Iron Oxides in the Reaction of Low-Temperature Ozone Decomposition

“…Iron oxides are commonly used in many fields of science and technology [1]. In particular, Fe 3 O 4 , γ-and α-Fe 2 O 3 , as well as α-and β-FeO(OH) are used as catalysts in the case of oxidation of organic compounds with ozone [2][3][4][5][6] and hydrogen peroxide [7,8]. Phase compositions of catalysts based on iron oxides depend on an iron salt concentration, the nature of anion and precipitating agent, temperature and duration of hydrolysis, as well as on conditions of drying and calcination of solid precipitates [1,[9][10][11].…”

Activated Carbon-Spinels Composites for Waste Water Treatment

“…Ferrites formed from transition metals are widely studied, due to their use as magnetic materials, semiconductors, pigments, and catalysts. These are classified according to their crystallization structure: hexagonal (MFe 12 O 19 ), garnet (M 3 Fe 5 O 12 ), and spinel (MFe 2 O 4 ), where M is one or more divalent transition metals (Mn, Fe, Co, Ni, Cu, and Zn) [6]. The catalytic properties of the different ferrites are given by the transition metals present in the structure and the distribution of the same.…”