CO oxidation of Ni films supported by carbon fiber

Seo, Hyun Ook; Nam, Jong Won; Kim, Kwang-Dae; Sim, Jong Ki; Kim, Young Dok; Lim, Dong Chan

doi:10.1016/j.molcata.2012.05.001

Cited by 6 publications

(2 citation statements)

References 28 publications

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“…Indeed, Greiner et al [56] suggested the formation of Ni(OH) 2 rather than Ni 2 O 3 on the NiO surface, which was attributed to the higher thermodynamic stability of Ni(OH) 2 compared with Ni 2 O 3 . Consistent with this hypothesis, Seo et al [57] reported the formation of Ni(OH) 2 on a carbon fiber Ni film rather than Ni 2 O 3 as well.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 68%

Oxygen transport in Pr nickelates: Elucidation of atomic-scale features

et al. 2020

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Pr 2 NiO 4+δ oxide with a layered Ruddlesden-Popper structure is a promising material for SOFC cathodes and oxygen separation membranes due to a high oxygen mobility provided by the cooperative mechanism of oxygen migration involving both interstitial oxygen species and apical oxygen of the NiO 6 octahedra. Doping by Ca improves thermodynamic stability and increases electronic conductivity of Pr 2−x Ca x NiO 4+δ , but decreases oxygen mobility due to decreasing the oxygen excess and appearing of 1-2 additional slow diffusion channels at x ≥ 0.4, probably, due to hampering of cooperative mechanism of migration. However, atomic-scale features of these materials determining oxygen migration require further studies. In this work characteristics of oxygen diffusion in Pr 2−x Ca x NiO 4+δ (x = 0-0.6) are compared with results of the surface analysis by X-ray photoelectron spectroscopy and modeling of the interstitial oxygen migration by the plane-wave density functional theory calculations. According to the X-ray photoelectron spectroscopy data, the surface is enriched by Pr for undoped sample and by Ca for doped ones. The O1s peak at~531 eV corresponding to a weakly bound form of surface oxygen located at Pr cations disappears at~500°C. Migration of interstitial oxygen was modeled for a I4/mmm phase of Pr 2 NiO 4+δ . The interstitial oxygen anion repulses the apical one in the NiO 6 octahedra pushing it into the tetrahedral site between Pr cations. The calculated activation barrier of this migration is equal to 0.585 eV, which reasonably agrees with the experimental value of 0.83 eV obtained by the oxygen isotope exchange method. At the same time, for the model compound Ca 2 NiO 4+δ , obtained by isomorphic substitution of Pr by Ca in Pr 2 NiO 4+δ , calculations implied formation of the peroxide ion comprised of interstitial and lattice oxygen species not revealed in the case of incomplete substitution (up to PrCaNiO 4+δ composition).Hence, calculations in the framework of the plane-wave density functional theory provide a realistic estimation of specificity of oxygen migration features in Pr 2 NiO 4+δ doped by alkaline-earth metals.

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Section: X-ray Photoelectron Spectroscopymentioning

confidence: 68%

Oxygen transport in Pr nickelates: Elucidation of atomic-scale features

et al. 2020

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“…Recent studies have demonstrated that Ni can be used to catalyze the conversion of CO to CO 2 at lower temperatures in contrast to the high temperatures required by noble metals [59][60][61][62]. Other studies have indicated that a thin film of NiO deposited on the support surface possesses a high reactivity and good stability for different processes such as ethanol decomposition, CO, and VOC oxidation [63][64][65][66].…”

Section: Introductionmentioning

confidence: 99%

Moderate Temperature Treatment of Gas-Phase Volatile Organic Toluene Using NiO and NiO–TiO2 Nano-catalysts: Characterization and Kinetic Behaviors

Almomani

Bhosale

Khraisheh

2020

Waste Biomass Valor

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For the first time, the potential of Ni/NiO and NiO–TiO2 nano-catalysts for the oxidation of toluene under moderate temperatures was investigated. The nano-catalysts were prepared using the solution combustion synthesis method (SCSM) and the effect of the composition of nano-catalysts, the inlet toluene concentration $$([\text{C}_{7} {\text{H}}_{8}]_{in})$$ ( [ C 7 H 8 ] in ) , the relative humidity (RH), and the temperature on the percentage of toluene conversion ($$\% {\text{TN}}_{Conv.} )$$ % TN C o n v . ) were subsequently examined. Results revealed that the nano-catalysts synthesized with a low fuel-to-metal ratio produced pure NiO, which has significant catalytic activity toward the conversion of toluene. Conversely, the high fuel-to-metal ratio generated a nano-catalysts that contains a mixture of Ni/NiO or pure Ni with low activity toward the conversion of toluene. Adding NiO to TiO2 increased the surface area of the catalyst, augmented the catalyst active sites, enhanced the oxidation of toluene, and increased CO2 selectivity ($${\text{S}}_{{{\text{CO}}_{2} }}$$ S CO 2 ). NiO and NiO–TiO2 nano-catalysts exhibited higher reaction rates, significant catalyst turnover frequency, and low activation energy. The obtained results revealed that the SCSM is a promising synthesis method for producing NiO or NiO–TiO2 nano-catalysts, which can be employed successfully for the removal of toluene from gas streams. Graphic Abstract

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