Observation of c-CuFe2O4 nanoparticles of the same crystallite size in different nanocomposite materials: The influence of Fe3+ cations

Nikolić, Violeta N.; Vasić, Milica; Kisić, Danilo

doi:10.1016/j.jssc.2019.04.007

Cited by 32 publications

(12 citation statements)

References 72 publications

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“…In a recent paper, Nikolić et al 41 proved that an increase on the Fe content favours the cubic phase stabilization. They provide a deep discussion about the Fe 3+ incorporation on the CuO 42 structure through the Cu 2+ release to form the CuFe 2 O 4 .…”

Section: Resultsmentioning

confidence: 99%

“…In a recent paper, Nikolić et al . proved that an increase on the Fe content favors cubic phase stabilization.…”

Section: Results and Discussionmentioning

confidence: 99%

“…These conclusions agree with our explanation. Although all of our samples have been prepared with the same Fe 3+ /Cu 2+ ratio (contrary to the experimental procedure presented in ref ), it is the gel burning process that quenches a premature cubic phase with a nonequilibrium cation distribution. This is then the key point because it affects the Cu 2+ side occupancy (i.e., to the Jahn–Teller effect) and the Fe content on the CuFe 2 O 4 structure.…”

Section: Results and Discussionmentioning

confidence: 99%

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Influence of the Synthesis Route in Obtaining the Cubic or Tetragonal Copper Ferrite Phases

Rosa

Segarra

2020

Inorg. Chem.

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In this work, magnetic copper ferrite nanoparticles are synthesized by polymer-assisted sol-gel and co-precipitation methods. The obtained purity and particle size reach values of 96 % and 94 nm, respectively. Evident differences in the crystal structure have been found in the synthesized nanoparticles. A tetragonal structure is formed by the sol-gel method, while the cubic form is obtained when the co-precipitation approach is used. This work provides an experimental evidence of the formation of both phases by using the same reactants and thermal conditions, and only modifying the technical procedure. The formation and stability of each phase is analysed by temperature dependent measurements, and the observed crystal structure differences are used to propose a potential fundamental explanation to our observations based on a difference on the cations' distribution and the Jahn-Teller distortion. Moreover, different copper ferrite purity and particle sizes are found when using each of the methods. The spherical shape of the particles and their tendency to sinter forming micrometric clusters are observed by electron microscopy. Finally, the divergence in magnetization between the samples prepared by each method support our argument about the different cations' distribution and open the door to a wide range of different technological applications for these materials.

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Section: Resultsmentioning

confidence: 99%

“…In a recent paper, Nikolić et al . proved that an increase on the Fe content favors cubic phase stabilization.…”

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

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Influence of the Synthesis Route in Obtaining the Cubic or Tetragonal Copper Ferrite Phases

Rosa

Segarra

2020

Inorg. Chem.

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“…The transformed Cu–O bond is shortened after calcination. , The shortened Cu–O bond inevitably induces electronic reconfiguration in the Cu–O combo and causes slight enhancement of the electronic density of Cu 2+ species (to generate Cu (2−δ)+ sites); thus, binding energies for Cu–O and Cu–OH exhibit strong red shifts. More importantly, the shortened Cu–O bond in the thermally annealed sample will also facilitate electronic reconfiguration promoted by the Jahn–Teller effect (inset of Figure a). − The tetrahedral nature of CuO crystals undergoes field energy splitting, and d π orbitals, namely d xy , d xz , and d yz , will be elevated from d x 2 – y 2 and d z 2 (d σ orbital), as generally accepted for field energy theory . However, the shortened Cu–O bond, predominantly caused by material surface restructuring during −OH removal, contributes further to the orbital split of d x 2 – y 2 and d z 2 , leading d z 2 close to the three d π orbitals.…”

Section: Resultsmentioning

confidence: 91%

Surface/Lattice Oxygen Synergism of Durable CuO Catalysts for Tandem Dehydrogenation–Oxidation of Glycerol to Carboxylic Acids in Oxygen-Free Medium

Wang

et al. 2022

ACS Sustainable Chem. Eng.

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Catalytic dehydrogenation–oxidation of bio-oxygenates to carboxylic acids and green H2 has been considered a key technology for biorefineries. Composition, size, and morphology are critical parameters for solid catalysts. However, the synergism of surface/lattice oxygen in inexpensive metal oxide catalysts is largely unexplored in this area. In this work, a systematic study on the surface/lattice oxygen synergism of crystallized CuO catalysts has been performed using glycerol dehydrogenation as an example. The key finding is that surface oxygen contributes to enhanced C–H bond activation, while lattice oxygen is key for tandem dehydrogenation–oxidation reactions. Thus, the crystallized CuO catalysts display a 2-fold enhancement in activity and 7-fold improvement in the durability of CuO catalysts, leading to almost 93% reduction of Cu leaching with negligible deactivation. The methodology discussed in this work will provide insights into the rational design of cost-effective CuO materials for other important aqueous dehydrogenation reactions in the chemical industry.

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“…In recent years, special attention of scientists was given to obtaining fine-crystalline materials with a spinel structure. For synthesis, several technological methods are used, such as precipitation and calcination [16,17], hydrothermal synthesis [18][19][20], synthesis during the decomposition of an organic precursor [4,6,21]. Nanosized materials exhibit increased activity in catalytic and adsorption processes requiring structurally sensitive properties.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and catalytic properties of nickel (II) - copper (II) ferrite

et al. 2021

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This work studies the process of formation of the spinel structure of nickel (II) -copper (II) ferrite. A possible mechanism for the formation of single-phase spinel samples is considered. It consists of the stage of formation of chelate complexes of nickel (II), copper (II), iron (III) cations with citric acid and their subsequent thermal decomposition. The materials obtained are studied by X-ray phase analysis and the BET technique. The catalytic activity of the synthesized ferrite Cu0.5Ni0.5Fe2O4 in the process of oxidative destruction of methyl orange in the presence of hydrogen peroxide is established. It is shown that the process is significantly accelerated with increasing temperature. The activation energy of the reaction was computed. It was found that the activation energy decreases in the presence of a catalyst. The results can be used to obtain materials suitable for industrial wastewater treatment using organic dyes in production cycles.

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Observation of c-CuFe2O4 nanoparticles of the same crystallite size in different nanocomposite materials: The influence of Fe3+ cations

Cited by 32 publications

References 72 publications

Influence of the Synthesis Route in Obtaining the Cubic or Tetragonal Copper Ferrite Phases

Influence of the Synthesis Route in Obtaining the Cubic or Tetragonal Copper Ferrite Phases

Surface/Lattice Oxygen Synergism of Durable CuO Catalysts for Tandem Dehydrogenation–Oxidation of Glycerol to Carboxylic Acids in Oxygen-Free Medium

Synthesis and catalytic properties of nickel (II) - copper (II) ferrite

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