Amine ligand-based hydrothermal synthesis of Co 3 O 4 nanoparticles, characterization and magnetic study

Mansournia, Mohammadreza; Rakhshan, Narges

doi:10.1016/j.molstruc.2016.07.080

Cited by 25 publications

(11 citation statements)

References 42 publications

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“…The prominent peak of the Co2p3/2 level is deconvoluted into two peaks at 779.78 and 794.49 eV [Figure c], attributed to the Co 3+ 2p 3/2 (in octahedron site species) and Co 2+ 2p3/2 (in tetrahedral sites species) conformation, respectively . The exact oxidation state of Co can be induced from the spin–orbit splitting of the Co2p (2p 1/2 ) peak at 794.35–794.45 and 795.35–795.7 eV, assigned to Co 3+ 2p1/2 and Co 2+ 2p1/2 configurations, respectively . Moreover, the shake-up peaks of the Co 3 O 4 phase are also observed at 789 and 803.8 eV.…”

Section: Resultsmentioning

confidence: 70%

“…The FT-IR spectrum of the Co 3 O 4 NPs was recorded from 500 to 4000 cm –1 , and the results are shown in the supplementary information (Figure S5). As shown in Figure a, the broad IR band at 1097 cm –1 is assigned to the symmetric stretching of the CO 3 2– ion, and the two sharp peaks at 676 and 571 cm –1 are ascribed to the (Co–O) linkage fingerprint stretching vibrational modes that consequently confirm the formation of Co 3 O 4 NPs. , In specific, the bands at 676 and 571 cm –1 are characteristic of Co–O bonding vibrations, signifying the occurrence of Co 3+ ions and Co 2+ ions at the octahedral and tetrahedral sites, respectively, of the spinel-Co 3 O 4 crystal lattice.…”

Section: Resultsmentioning

confidence: 99%

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Mesoporous Octahedron-Shaped Tricobalt Tetroxide Nanoparticles for Photocatalytic Degradation of Toxic Dyes

Sonkusare

Chaudhary

Bhusari³

et al. 2020

ACS Omega

120

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The present article reports a facile approach to fabrication of mesoporous octahedron-shaped tricobalt tetroxide nanoparticles (Co 3 O 4 NPs) with a very narrow size distribution for eco-friendly remediation of toxic dyes. Co 3 O 4 NPs were fabricated by a sol−gel process using cobalt chloride hexahydrate (CoCl 2 • 6H 2 O) and monosodium succinate (C 4 H 5 O 4 Na) as a chelating/ structure-directing agent and sodium dodecyl sulfate as a surfactant. Moreover, the phase structure, elemental composition, and thermal and morphological facets of Co 3 O 4 NPs were investigated using XRD, FT-IR, EDS, Raman, XPS, TGA, SEM, and TEM techniques. The face-centered cubic spinel crystalline structure of the Co 3 O 4 NPs was confirmed by XRD and SEM, and TEM analysis revealed their octahedron morphology with a smooth surface. Moreover, the narrow pore size distribution and the mesoporous nature of the Co 3 O 4 NPs were confirmed by Brunauer−Emmett−Teller measurements. The photocatalytic activity of Co 3 O 4 NPs for degradation of methyl red (MR), Eriochrome Black-T (EBT), bromophenol blue (BPB), and malachite green (MG) was examined under visible light irradiation, and the kinetics of the dye degradation was pseudo-zero-order with the rate constant in the order of MR > EBT > MG > BPB. Furthermore, the mechanism of photo-disintegration mechanism of the dye was examined by a scavenging test using liquid chromatography−mass chromatography, and its excellent photodegradation activities were attributed to the photogenerated holes (h + ), superoxide (O 2 − ) anions, and hydroxyl ( • OH) radicals. Finally, the synergistic effect of the nano-interconnected channels with octahedron geometry, mesoporous nature, and charge transfer properties along with photogenerated charge separations leads to an enhanced Co 3 O 4 photocatalytic activity.

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Section: Resultsmentioning

confidence: 70%

Section: Resultsmentioning

confidence: 99%

Mesoporous Octahedron-Shaped Tricobalt Tetroxide Nanoparticles for Photocatalytic Degradation of Toxic Dyes

Sonkusare

Chaudhary

Bhusari³

et al. 2020

ACS Omega

120

View full text Add to dashboard Cite

show abstract

“…Because of the strong crystal-field effect of the latter, the energy gap between the t 2g and e g levels in cobalt amine complexes is generally large compared to that of cobalt aqua complexes. As a result, the system prefers to oxidize by losing one electron from its e g level to obtain stability, and mere contact with air can effectively drive the oxidation process of Co II to Co III . , This further gets reflected in the lower reduction potential value of Co III /Co II under ammoniacal conditions ( E °= 0.10 V).…”

Section: Resultsmentioning

confidence: 99%

“…As a result, the system prefers to oxidize by losing one electron from its e g level to obtain stability, and mere contact with air can effectively drive the oxidation process of Co II to Co III . 41,42 This further gets reflected in the lower reduction potential value of Co III /Co II under ammoniacal conditions (E°= 0.10 V).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Paradoxical Observance of “Intrinsic” and “Geometric” Oxygen Evolution Electrocatalysis in Phase-Tuned Cobalt Oxide/Hydroxide Nanoparticles

Ganguli

Koppisetti

Ghosh

et al. 2019

ACS Appl. Nano Mater.

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Excellent activity of cobalt oxides/hydroxides towards electrocatalytic oxygen evolution reaction (OER) demands the development of a unified protocol to synthesize different phases of these materials. In this paper, a low-temperature (120 °C) solvothermal method was developed to synthesize pure phase Co 3 O 4 , Co 2 (OH) 3 Cl, and Co II 1−x Co III x (OH) 2 Cl x •nH 2 O [HT(II,III)] and detailed analyses of their formation mechanism, intrinsic as well as geometric activity toward OER electrocatalysis, were carried out. This method employs a variety of amines to facilitate the Co II to Co III oxidation, which otherwise requires continuous gas (purified air/oxygen) flow or usage of oxidizing agents for reactions carried out below 150 °C. The choice of solvent (water/ water−ethanol mixture) was also found to play a pivotal role in the reaction pathway, phase, and morphology of the resulting products due to changes in the pH of the reaction medium. In contrast to the geometric OER activity that follows the order HT(II,III) > Co 2 (OH) 3 Cl > Co 3 O 4 , the intrinsic activity (from specific activity and turnover frequency) of Co 2 (OH) 3 Cl was found to be significantly higher compared to that of HT(II,III). Underlying factors behind this observation were probed and found to be the (i) higher OER active site density, (ii) larger interlayer spacing, (iii) slitlike pore geometry, (iv) amorphous and turbostratic nature, and (v) lower charge-transfer resistance of HT(II,III). While for HT(II,III) and Co 2 (OH) 3 Cl, structural and morphological changes coupled with low charge-transfer resistance led to the rapid generation of active catalytic centers that promote the electrocatalytic process, high charge-transfer resistance and reluctance toward any structural change were found to be responsible for the poor OER electrocatalytic performance of Co 3 O 4 .

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“…The detailed synthetic procedures are described in the Methods section. This synthesis method is advantageous compared with other methods in the literature [43,44] for three reasons. First, the ratio of the amount of retrieved NPs to that of solvent used during the synthesis process is relatively large.…”

Section: Synthesis Of Metal-oxide Nanoparticlementioning

confidence: 99%

Room‐Temperature‐Processable Highly Reliable Resistive Switching Memory with Reconfigurability for Neuromorphic Computing and Ultrasonic Tissue Classification

Kim

Bang

Baac

et al. 2023

Adv Funct Materials

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Reversible metal-filamentary mechanism has been widely investigated to design an analog resistive switching memory (RSM) for neuromorphic hardware-implementation. However, uncontrollable filament-formation, inducing its reliability issues, has been a fundamental challenge. Here, an analog RSM with 3D ion transport channels that can provide unprecedentedly high reliability and robustness is demonstrated. This architecture is realized by a laser-assisted photo-thermochemical process, compatible with the backend-of-line process and even applicable to a flexible format. These superior characteristics also lead to the proposal of a practical adaptive learning rule for hardware neural networks that can significantly simplify the voltage pulse application methodology even with high computing accuracy. A neural network, which can perform the biological tissue classification task using the ultrasound signals, is designed, and the simulation results confirm that this practical adaptive learning rule is efficient enough to classify these weak and complicated signals with high accuracy (97%). Furthermore, the proposed RSM can work as a diffusive-memristor at the opposite voltage polarity, exhibiting extremely stable threshold switching characteristics. In this mode, several crucial operations in biological nervous systems, such as Ca 2+ dynamics and nonlinear integrate-and-fire functions of neurons, are successfully emulated. This reconfigurability is also exceedingly beneficial for decreasing the complexity of systems-requiring both drift-and diffusive-memristors.

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Amine ligand-based hydrothermal synthesis of Co 3 O 4 nanoparticles, characterization and magnetic study

Cited by 25 publications

References 42 publications

Mesoporous Octahedron-Shaped Tricobalt Tetroxide Nanoparticles for Photocatalytic Degradation of Toxic Dyes

Mesoporous Octahedron-Shaped Tricobalt Tetroxide Nanoparticles for Photocatalytic Degradation of Toxic Dyes

Paradoxical Observance of “Intrinsic” and “Geometric” Oxygen Evolution Electrocatalysis in Phase-Tuned Cobalt Oxide/Hydroxide Nanoparticles

Room‐Temperature‐Processable Highly Reliable Resistive Switching Memory with Reconfigurability for Neuromorphic Computing and Ultrasonic Tissue Classification

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