Hydrogenation of substituted aromatic nitrobenzenes over 1% 1.0wt.%Ir/ZrO2 catalyst: Effect of meta position and catalytic performance

Campos, Cristian H.; Torres, Cecilia C.; Oportus, Marcelo; Peña, M.A.; Fierro, J.L.G.; Reyes, Patricio

doi:10.1016/j.cattod.2013.03.037

Cited by 45 publications

(25 citation statements)

References 55 publications

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“…The formation of both zero valent (Ir 0 ) and partially oxidized iridium (Ir d? ) has been previously established in H 2 -TPR studies over Ir/ZrO 2 [63] and Ir/SiO 2 [55] catalysts and is also confirmed here by TEM. HT calcination is expected to enhance sintering of the Ir crystallites and thus, render their deep oxidation difficult, in agreement with Wögerbauer et al [60] who found that large Ir crystallites cannot be fully oxidized up to 970°C.…”

Section: Catalyst Characterization Studiessupporting

confidence: 82%

“…4a, b shows that the maximum of the LT peak for the Ir/YSZ catalyst shifts to the opposite direction compared to that for the LT peak observed for Ir/ Al 2 O 3 . However, it should be noted that although most of the studies agree that iridium crystallite size has a pronounced effect on reduction temperature [52][53][54][55][56]63], there is a controversy on whether reduction at low temperatures is favored by small or large crystallites. Hydrogen-TPR and, as will be discussed below, TEM results of the present study imply that the reduction temperature of IrO x species depends not only on iridium crystallite size but also on variations of iridium particles morphology.…”

Section: Catalyst Characterization Studiesmentioning

confidence: 94%

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Dry Reforming of Methane: Catalytic Performance and Stability of Ir Catalysts Supported on γ-Al2O3, Zr0.92Y0.08O2−δ (YSZ) or Ce0.9Gd0.1O2−δ (GDC) Supports

et al. 2015

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The impact of the support on the Ir-catalyzed dry (CO 2 ) reforming of methane (DRM) reaction is explored in the present study. With this aim, supported iridium catalysts Ir/c-Al 2 O 3 , Ir/YSZ and Ir/GDC with 1 wt% iridium loading, using c-Al 2 O 3 , 8 mol% Y 2 O 3 stabilized ZrO 2 (YSZ: Zr 0.92 Y 0.08 O 2-d ) and 10 mol% Gd 2 O 3 doped CeO 2 (GDC: Ce 0.9 Gd 0.1 O 2-d ) as supports were comparatively studied in the temperature range of 400-850°C. The feasibility of tuning the catalytic performance and/or stability of the Ir active phase during DRM reaction, via support-induced interactions, was investigated. All catalysts were found to be extremely active and stable over time on stream. No significant effects induced by the support were observed at the high operating temperature of DRM. However, opposite to Ir/cAl 2 O 3 and Ir/YSZ samples, Ir/GDC provides the benefit to be stable in oxidation steps and/or oxidation-reduction cycles. This is of significant practical importance since such treatment procedures are often used in practice for catalysts regeneration. Besides catalytic performance measurements, extended hydrogen temperature-programmed reduction experiments, supported further by transmission electron microscopy characterization studies were carried out in order to reveal the impact of the support on the aforementioned stability and its origin.

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Section: Catalyst Characterization Studiessupporting

confidence: 82%

Section: Catalyst Characterization Studiesmentioning

confidence: 94%

Dry Reforming of Methane: Catalytic Performance and Stability of Ir Catalysts Supported on γ-Al2O3, Zr0.92Y0.08O2−δ (YSZ) or Ce0.9Gd0.1O2−δ (GDC) Supports

et al. 2015

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“…6b,7 Hydrazine, as an indirect hydrogen source, has been shown to be effective in nitro reduction. 8 Thus, our study started with evaluating the reduction of 1-bromo-4-( tert -butyl)-2-nitrobenzene ( 1a ) by Pd/C and hydrazine.…”

mentioning

confidence: 99%

Selective Reduction of Halogenated Nitroarenes with Hydrazine Hydrate in the Presence of Pd/C

Frett

2014

Synlett

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“…Moreover, 4-nitro acetophenone that possesses two unsaturated functionalities (-C=O and -NO 2 ) just led to the reduction of nitro group in high yield, but not -C=O functionality, confirming the high selectivity of Pd@C towards hydrogenation of -NO 2 functionality. In addition, it can be observed that the presence of electron-donating group (-NH 2 ) led to decrease of the yield of the reaction due to the stabilization of resonance effects to the nitro functionality 54 . According to the literature, in the case of halogen substituted reagent, dehalogenation may be responsible for low yield 55 .…”

Section: Results and Discussion Catalyst Characterization The Xrd Patmentioning

confidence: 99%

Preparation of palladated porous nitrogen-doped carbon using halloysite as porogen: disclosing its utility as a hydrogenation catalyst

Sadjadi

Malmir

Lazzara

et al. 2020

Sci Rep

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in this article, halloysite nanoclay (Hal) was used as porogen for the synthesis of nitrogen doped porous carbon material with high specific surface area and pore volume. To this purpose, polymerization of melamine and terephthalaldehyde (Mt) was performed in the presence of amine-functionalized carbon coated Hal (Hal@Glu-2N) that was prepared from hydrothermal treatment of Hal and glucose. Then, the prepared nanocomposite was palladated and carbonized to afford Pd@Hal@C. To further improve the textural properties of the nanocomposite, and introduce more pores in its structure, Hal nanotubes were etched. the characterization of the resulting compound, pd@c, and comparing it with pd@ Hal@C, showed that etching of Hal significantly increased the specific surface area and pore volume in pd@c. pd@c was successfully used as a heterogeneous catalyst for promoting hydrogenation of nitroarens in aqueous media using hydrogen with atmospheric pressure as a reducing agent. the comparison of the structural features and catalytic activity of the catalyst with some control catalysts, including, Pd@Hal, Pd@Hal@Glu, Pd@Hal@Glu-MT and Pd@Hal@C confirmed that nitrogen groups in c could improve the pd anchoring and suppress its leaching, while etching of Hal and introduction of more pores could enhance the catalytic activity through facilitating the mass transfer. Carbon materials are among the most used compounds for diverse range of applications such as electrode materials, energy storage, catalysis and water treatment 1-5. The function of carbon materials is strongly dependent on their physical and chemical properties such as specific surface area, porosity and the presence of heteroatoms in the carbon structure. According to the literature, doping of heteroatoms such as nitrogen atoms in the carbon structure can improve the electric and chemical properties of carbon materials and expand their applications 2,3,6-10. To achieve nitrogen doped carbon, carbonization of heteroatom-containing substrates has been suggested. However, the control of the textural properties of the carbon material through simple carbonization is challenging. To furnish a solution to this issue, use of template and structural guides such as KIT and mesoporous silica has been suggested 11,12. However, most of the templates are synthetic and use of them is costly and lingers the synthetic process of carbon materials 13. Halloysite is a natural clay mineral (imperial formula of Al 2 Si 2 O 5 (OH) 4 •nH 2 O) with tubular morphology and chemistry similar to Kaolin 14-23. This nanoclay has been successfully applied for various applications such as material chemistry, catalysis and smart delivery 18,24-26. It should be noted that the specific geological origin of Hal affects the morphological features and size polydispersity of nanotubes 27. Moreover, the chemistry of the surface of Hal is readily tuned-able and can be modified through surface functionalization 15,16,27. Reduction of nitro group to amine functionality is an industrially attractive chemical transf...

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Hydrogenation of substituted aromatic nitrobenzenes over 1% 1.0wt.%Ir/ZrO2 catalyst: Effect of meta position and catalytic performance

Cited by 45 publications

References 55 publications

Dry Reforming of Methane: Catalytic Performance and Stability of Ir Catalysts Supported on γ-Al2O3, Zr0.92Y0.08O2−δ (YSZ) or Ce0.9Gd0.1O2−δ (GDC) Supports

Dry Reforming of Methane: Catalytic Performance and Stability of Ir Catalysts Supported on γ-Al2O3, Zr0.92Y0.08O2−δ (YSZ) or Ce0.9Gd0.1O2−δ (GDC) Supports

Selective Reduction of Halogenated Nitroarenes with Hydrazine Hydrate in the Presence of Pd/C

Preparation of palladated porous nitrogen-doped carbon using halloysite as porogen: disclosing its utility as a hydrogenation catalyst

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