X-ray absorption study of the local structure at the NiO/oxide interfaces

Preda, I.; Soriano, L.; Díaz-Fernández, D.; Domínguez-Cañizares, G.; Gutiérrez, Alejandro; Castro, G.R.; Chaboy, J.

doi:10.1107/s0909049513012417

Cited by 13 publications

(9 citation statements)

References 32 publications

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“…The XANES spectrum of metallic nickel is characterized by the presence of two peaks of approximately the same intensity at the absorption edge in the region of 8350–8360 eV, as well as the pre-edge feature in the form of a shoulder at 8335 eV (1s→3d transition). In contrast, the spectrum of NiO has an intense peak at the absorption edge in the region of 8350 eV [ 66 , 67 ]. The Ni K-edge XANES spectra of the SG catalysts have a pronounced peak at 8351.0 eV, which is characteristic of NiO.…”

Section: Resultsmentioning

confidence: 99%

Ni–Cu High-Loaded Sol–Gel Catalysts for Dehydrogenation of Liquid Organic Hydrides: Insights into Structural Features and Relationship with Catalytic Activity

et al. 2021

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The heightened interest in liquid organic hydrogen carriers encourages the development of catalysts suitable for multicycle use. To ensure high catalytic activity and selectivity, the structure–reactivity relationship must be extensively investigated. In this study, high-loaded Ni–Cu catalysts were considered for the dehydrogenation of methylcyclohexane. The highest conversion of 85% and toluene selectivity of 70% were achieved at 325 °C in a fixed-bed reactor using a catalyst with a Cu/Ni atomic ratio of 0.23. To shed light on the relationship between the structural features and catalytic performance, the catalysts were thoroughly studied using a wide range of advanced physicochemical tools. The activity and selectivity of the proposed catalysts are related to the uniformity of Cu distribution and its interaction with Ni via the formation of metallic solid solutions. The method of introduction of copper in the catalyst plays a crucial role in the effectiveness of the interaction between the two metals.

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Section: Resultsmentioning

confidence: 99%

Ni–Cu High-Loaded Sol–Gel Catalysts for Dehydrogenation of Liquid Organic Hydrides: Insights into Structural Features and Relationship with Catalytic Activity

et al. 2021

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“…At that, the metallic Ni XANES spectrum revealed the presence of two peaks in the region of 8350-8360 eV of approximately the same intensity, as well as a shoulder at 8335 eV (transition 1s → 3d). In contrast to the XANES spectrum of metallic nickel, the NiO spectrum shows an intense peak at 8350 eV [65,66]. From Figure 5a it is evident that in the case of our test sample NiCuMo-P-SiO2 the Ni K-edge XANES spectrum had a shape similar to that of metallic nickel.…”

mentioning

confidence: 75%

Effect of Temperature on the Hydrotreatment of Sewage Sludge-Derived Pyrolysis Oil and Behavior of Ni-Based Catalyst

et al. 2020

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The high-energy potential of wastewater sewage sludge (SS) produced in large amounts around the world makes it an attractive feedstock for fuels and energy sectors. Thermochemical valorization relying on pyrolysis of SS followed by hydrotreatment of pyrolysis oil (Py-SS) might even allow the integration of SS into existing oil refineries. In the present study, catalytic hydrotreatment of Py-SS was performed over a NiCuMo-P-SiO2 catalyst in a batch reactor at temperatures in the range of 200–390 °C. Due to sulfur presence in the feed, the increasing reaction temperature induced in situ transformation of metallic Ni into Ni3S2 in the catalyst. In contrast, the Ni3P active phase possessed remarkable stability even at the harshest reaction conditions. The oxygen content in the reaction products was decreased by 59%, while up to 52% of N and 89% of S were removed at 390 °C. The content of free fatty acids was greatly reduced by their conversion to n-alkanes, while the larger amount of volatile aromatics was generated from high molecular mass compounds. The quality of oil-derived products greatly changed at elevated temperatures, providing strong evidence of effective upgrading via decarboxy(ny)lation, hydrogenation, and hydrocracking transformations.

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“…Instead, Krüger used a first-principles multichannel multiple-scattering approach to show that the absence of a split structure in feature A should be addressed to the loss of long-range order on a length scale of 1 nm [22]. Recently, Preda et al showed for NiO/SiO 2 that in addition to the lost of long-range order, distortion at the interface induce changes in the XAS spectra [23]. It should be noticed that Ti-L 2,3 spectra with typical features of anatase and rutile TiO 2 were obtained with our ALD system when TTIP was used in connection with O 2 -plasma instead of water [17].…”

Section: Resultsmentioning

confidence: 99%

Quantum size effects in TiO₂ thin films grown by atomic layer deposition

Tallarida¹,

Das²,

Schmeißer³

2014

Beilstein J. Nanotechnol.

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SummaryWe study the atomic layer deposition of TiO2 by means of X-ray absorption spectroscopy. The Ti precursor, titanium isopropoxide, was used in combination with H2O on Si/SiO2 substrates that were heated at 200 °C. The low growth rate (0.15 Å/cycle) and the in situ characterization permitted to follow changes in the electronic structure of TiO2 in the sub-nanometer range, which are influenced by quantum size effects. The modified electronic properties may play an important role in charge carrier transport and separation, and increase the efficiency of energy conversion systems.

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X-ray absorption study of the local structure at the NiO/oxide interfaces

Cited by 13 publications

References 32 publications

Ni–Cu High-Loaded Sol–Gel Catalysts for Dehydrogenation of Liquid Organic Hydrides: Insights into Structural Features and Relationship with Catalytic Activity

Ni–Cu High-Loaded Sol–Gel Catalysts for Dehydrogenation of Liquid Organic Hydrides: Insights into Structural Features and Relationship with Catalytic Activity

Effect of Temperature on the Hydrotreatment of Sewage Sludge-Derived Pyrolysis Oil and Behavior of Ni-Based Catalyst

Quantum size effects in TiO₂ thin films grown by atomic layer deposition

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X-ray absorption study of the local structure at the NiO/oxide interfaces

Cited by 13 publications

References 32 publications

Ni–Cu High-Loaded Sol–Gel Catalysts for Dehydrogenation of Liquid Organic Hydrides: Insights into Structural Features and Relationship with Catalytic Activity

Ni–Cu High-Loaded Sol–Gel Catalysts for Dehydrogenation of Liquid Organic Hydrides: Insights into Structural Features and Relationship with Catalytic Activity

Effect of Temperature on the Hydrotreatment of Sewage Sludge-Derived Pyrolysis Oil and Behavior of Ni-Based Catalyst

Quantum size effects in TiO2 thin films grown by atomic layer deposition

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Quantum size effects in TiO₂ thin films grown by atomic layer deposition