Effect of thermal treatment on the kinetics and sintering characteristics of nickel hydroxide as a precursor for the thermal genesis of nickel oxide catalyst

Gabr, R.M.; El-Naimi, A.N.; Al-Thani, M.G.

doi:10.1016/0040-6031(92)85029-u

Cited by 14 publications

(13 citation statements)

References 23 publications

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“…The focal point of the Swaddle and Long study was to investigate the hydrothermal decomposition of nickel oxide, so dry nickel hydroxide decomposition tests were only performed for comparison, and not for the detailed study of the dry decomposition process itself. While most of the literature studies as well as our study observed a deceleratory reaction, Gabr et al [22] conversely reported acceleratory behavior along with a nucleation and growth mechanismm, along with a much higher activation energy. The temperature range for their study was somewhat higher than most of the other literature studies, 250-350°C, and the authors reported (and modelled) significant sintering above 310°C.…”

Section: Isothermal-a Model Fitting (10 Mg Sample Mass)supporting

confidence: 46%

“…This reaction slowing effect has often been observed in the literature, although the effect is not always addressed [9-11, 29, 30]. Gabr et al proposed water escape inhibition at higher temperatures and conversions [22]. Hazell and Irving proposed that adsorbed water masks continued reaction measured by mass change above 60% conversion based upon IR absorption data [20].…”

Section: Isothermal-a Model Fitting (10 Mg Sample Mass)mentioning

confidence: 85%

“…For unripened (wet) nickel hydroxide, E a = 114 kJ/mol, for ripened (dry) nickel hydroxide, E a = 132 kJ/mol. The highest literature activation energies was reported as 177 kJ/mol by Gabr et al [22] for isothermal dynamic air conditions in the range of 250-350°C. An Avrami-Erofeyev nucleation and growth mechanism was proposed, although the geometrydefining Avrami-Erofeyev exponent was not provided.…”

Section: Introductionmentioning

confidence: 98%

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Isothermal decomposition kinetics of nickel (II) hydroxide powder

Carney

Chinn

Doğan

et al. 2015

Journal of Alloys and Compounds

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Nickel (II) hydroxide powder was investigated by thermogravimetry for isothermal decomposition kinetics and verification of the Ni-O-H ternary phase diagram at low temperatures. The activation energy and frequency factor were measured as E a = 134 kJ/mol and A = 1.27 × 10 10 s-1 , respectively. The validity of the first-order random nucleation model was confirmed, as opposed to diffusion and or moving-boundary models. The dependence of TGA results on specimen size was noted. The Ni-Ni(OH) 2-NiO phase triangle was confirmed. Accordingly, a thermodynamic description of the system was established in the Ni-rich corner, and the isotherm at room temperature is calculated.

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Section: Isothermal-a Model Fitting (10 Mg Sample Mass)supporting

confidence: 46%

Section: Isothermal-a Model Fitting (10 Mg Sample Mass)mentioning

confidence: 85%

Section: Introductionmentioning

confidence: 98%

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Isothermal decomposition kinetics of nickel (II) hydroxide powder

Carney

Chinn

Doğan

et al. 2015

Journal of Alloys and Compounds

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“…Nickel oxide (NiO) is a promising material, extensively used in catalysis, battery cathodes, gas sensors and electrochromic films. [1][2][3][4][5] Furthermore, bulk NiO is an antiferromagnetic (AFM) material with a Ne´el temperature of 523 K and can thus be used in a variety of magnetic applications, particularly as a pinning layer in spin valves and magnetic tunnel junctions. 6 Nanostructured AFM oxides have therefore recently gained increased attention.…”

Section: Introductionmentioning

confidence: 99%

Size and surface effects on the magnetic properties of NiO nanoparticles

Proença

Sousa

Pereira

et al. 2011

Phys. Chem. Chem. Phys.

146

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NiO nanoparticles (NPs) were prepared by a sol-gel process using the citrate route. The sol-gel parameters were tuned to obtain samples with different average particle sizes, ranging from 12 to 70 nm. Magnetic characterization revealed an increase in the blocking temperature with the diameter of the NPs and an increase in the effective magnetic anisotropy (K(eff)) with decreasing particle size. The magnetic moment per particle was calculated for all samples using the susceptibility value at T = 300 K. The number of uncompensated spins per NP was found to be proportional to n (n(S)≡ total number of spins), indicating that they are randomly distributed on the NP surface. For small diameters (<30 nm) the surface anisotropy constant was estimated, using, for NiO NPs, a recent model describing the evolution of K(eff) with particle size. Hysteretic loops performed at low temperatures after field cooling displayed loop shifts (∼6.5 kOe in the field axis and ∼0.18 emu g(-1) vertically), coercive field enhancement (H(C)≈ 4.8 kOe) and training effects for the smaller NPs. The sample with NPs of larger diameters presented magnetic properties close to those of bulk NiO.

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“…In recent years, NiO nanomaterials have been widely investigated for various technological applications including catalysis, battery cathodes, gas sensors, electrochromic films, and solar cells [1][2][3][4][5][6], and therefore it has become important to understand how material surfaces alter these magnetic and electronic properties of NiO.…”

Section: Introductionmentioning

confidence: 99%

Antiferromagnetic structures and electronic energy levels at reconstructed NiO(111) surfaces: ADFT+Ustudy

Kanai

2015

Phys. Rev. B

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ABSTRACT:We studied how the surface reconstruction and passivation influence the antiferromagnetic and electronic structures of NiO(111) surface using first-principles electronic structure calculations. These features lead to a surprisingly wide variety of different surface electronic structures, and some surfaces are even metallic. Different reconstructions and surface passivation were also found to qualitatively alter the charge-transfer band gap type of bulk NiO. At the same time, the antiferromagnetic character of bulk NiO in the <111> direction is retained even near the surface, and the magnetic moment quickly converges to the bulk value within a few surface layers.

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Effect of thermal treatment on the kinetics and sintering characteristics of nickel hydroxide as a precursor for the thermal genesis of nickel oxide catalyst

Cited by 14 publications

References 23 publications

Isothermal decomposition kinetics of nickel (II) hydroxide powder

Isothermal decomposition kinetics of nickel (II) hydroxide powder

Size and surface effects on the magnetic properties of NiO nanoparticles

Antiferromagnetic structures and electronic energy levels at reconstructed NiO(111) surfaces: ADFT+Ustudy

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