Selective Hydrogenation of Nitroaromatics by Colloidal Iridium Nanoparticles

Sharif, Md. J.; Maity, Prasenjit; Yamazoe, Seiji; Tsukuda, Tatsuya

doi:10.1246/cl.130333

Cited by 23 publications

(15 citation statements)

References 26 publications

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“…Especially, an Ir 8 cluster with a simple cubic motif acts as a building unit of the larger clusters due to the high stability of the square planar structure. Therefore, further enhancement or improvement of the catalytic properties of Ir nanocatalysts can be expected for a variety of reactions such as hydrogenation, − aerobic oxidation, CO 2 fixation, hydrazine decomposition, and quinoline synthesis by reducing the particle size to the subnanometer region.…”

Section: Introductionmentioning

confidence: 99%

Structural Evolution of Iridium Oxide Cluster Anions Ir_nO_m^– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

et al. 2019

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Geometric structures of small cluster anions of iridium oxide Ir n O m – (n = 5–8, m = 0–14) were investigated by ion mobility mass spectrometry (IMMS) and theoretical calculation to clarify the evolutional behavior of the binding modes of the O atoms and the motif of the Ir frameworks as a function of m. The collision cross sections (CCSs) for n = 5–7 determined by IMMS showed a monotonic increase with m, whereas those for n = 8 dropped abruptly by ∼10% at m = 11, which otherwise gradually increased with m. For n = 5, detailed comparison between the experimental CCS values and those calculated for various structural isomers revealed that the O atoms in Ir5O m – are preferentially bonded to terminal sites of the Ir5 – cores throughout m = 1–8: the Ir5 – cores retained compact motifs up to m = 5 but distorted significantly for m = 6–8. The experimental CCS values for Ir6O6 – and Ir7O7 – were also explained by on-top binding of O atoms while retaining the motifs of the Ir frameworks. The CCS values for n = 8 suggest that the O atoms are sequentially bonded to terminal sites of the cubic Ir8 frameworks for m = 1–6 and of the deformed Ir8 frameworks for m = 7–11. These on-top binding modes of the O atoms on small Ir clusters are in sharp contrast to the μ2 mode of the O atoms at bridge sites on the clusters of other transition metals and are ascribed to non-face-centered cubic (fcc) Ir frameworks. The sudden drop in the CCS values of Ir8O m – at m = 11 was associated with bond breakage in the Ir framework induced by transition of the binding mode of O atoms from an on-top motif to a μ2 bridging motif. These results suggest that the small Ir clusters exhibit novel oxidation catalysis by taking advantage of the unique chemical properties of O atoms adsorbed on the on-top sites on non-fcc Ir clusters.

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Section: Introductionmentioning

confidence: 99%

Structural Evolution of Iridium Oxide Cluster Anions Ir_nO_m^– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

et al. 2019

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“…The peak at around 2.51 Å is assigned to the Ir-M (M = Ir, Rh) shells, while the peak at around 1.57 Å is assigned to the Ir-O shells. [32,33] For IrSb and Ir 0.7 Rh 0.3 Sb, an additional peak arises at around 1.9 Å, which can be assigned to the Ir-Sb shells. In addition, wavelet transform is performed to visually examine the localized coordination of Ir, with results showing in Figure 3d,e and Figures S15 and S16 in the Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir₁₋_xRh_xSb Intermetallic Alloy for Hydrogen Evolution Reaction

Lin

Xiao

Huang

et al. 2022

Advanced Energy Materials

116

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with the H 1s band. Among these catalysts, noble metals such as Pt and Ir exhibit the best HER activity locating at the top of the volcano plot, due to the Sabatier's principle. [15][16][17] However, the earth abundance of noble metals is an inevitable and insurmountable obstacle for the practical application of noble metals. Alloying noble metals with high-abundance metals is a possible way to reducing the usage of noble metals while sustaining their high catalytical performance, which remains a challenging mission. [18][19][20] Metal sites in complexes usually exhibit insufficient adsorption ability for active *H species, due to the Coulomb repulsion. Suffering from the insufficient adsorption, the metal sites in many catalysts are inert. For example, the Mo sites in MoX 2 (X = S, Se) are inactive for HER. [21][22][23] To enhance the HER performance of metal sites in complex, novel metal sites with abundant electrons are proposed to strengthen the interaction with *H. Kobayashi et al. reported negatively charged Pt obtained by light doping of W through electrochemical cleaning of core/shell PtW@WO 3 nanoparticles, to enhance the HER activity significantly. [24] The negatively charged Pt atoms provide favorable hydrogen adsorption energy, resulting in an overpotential superior to commercial Pt. As another example, Wei et al. prepared Pt clusters on TiO 2 with rich O vacancies. [25] Reversed charge transfer from TiO 2 to Pt is realized to boost the hydrogen evolution.In this work, we prepared ternary Ir 1−x Rh x Sb intermetallic alloy as highly active electrocatalyst for HER. Due to the large difference in the reduction potential of Ir, Rh, and Sb cations, the Ir 1−x Rh x Sb cannot be synthesized by common solvothermal method. The arc-melting method was then used for the preparation of Ir 1−x Rh x Sb alloy. The electron transfer can be well regulated by modulating the content ratio. Ir atoms in IrSb exhibit negative valence state owing to the electron transfer form Sb to Ir, as revealed by both experimental data and first-principal calculations. The hydrogen adsorption ability of Ir sites is then highly strengthened due to the accumulated electrons. Furthermore, the HER activity of Ir 1−x Rh x Sb is closely modulated and optimized by Rh doping. As a result, the Ir 0.7 Rh 0.3 Sb sample exhibits the best HER activity, with an overpotential of 22 mV at 10 mA cm -2 and a Tafel slope of 47.6 mV dec -1 . This work provides insights into highly active alloys and sheds lights on the utilization of electron-abundant metal atoms.Alloying noble metals with non-noble metals is a promising method to fabricate catalysts, with the advantages of reduced noble metal usage and excellent activity. In this work, electron-abundant Ir/Rh sites, as highly active centers for the hydrogen evolution reaction (HER), are realized by fabricating Ir 1−x Rh x Sb alloys through the arc-melting method. The electron transfer from Sb to Ir/Rh makes the latter negatively charged, leading to considerably optimized adsorption for active H species dur...

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“…The selective hydrogenation of aromatic compounds (quinoline and its analogues, aromatic nitro compounds, aromatic ketones, aromatic aldehydes etc.) by means of heterogeneous catalysis is among the most important subjects in industrial organic chemistry . The controllable hydrogenation products of aromatic compounds are always of interest, as they offer various options for further derivatization.…”

Section: Introductionmentioning

confidence: 99%

Selective hydrogenation of aromatic compounds using modified iridium nanoparticles

Sun

2018

Applied Organom Chemis

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Till now, Ionic liquid-stabilized metal nanoparticles were investigated as catalytic materials, mostly in the hydrogenation of simple substrates like olefins or arenes. The adjustable hydrogenation products of aromatic compounds, including quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes, are always of special interest, since they provide more choices for additional derivatization. Iridium nanoparticles (Ir NPs) were synthesized by the H 2 reduction in imidazolium ionic liquid. TEM indicated that the Ir NPs is worm-like shape with the diameter around 12.2 nm and IR confirmed the modification of phosphine-functionalized ionic liquids (PFILs) to the Ir NPs. With the variation of the modifier, solvent and reaction temperature, substrate like quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes could be hydrogenated by Ir NPs with interesting adjustable catalytic activity and chemoselectivity.Ir NPs modified by PFILs are simple and efficient catalysts in challenging chemoselective hydrogenation of quinoline and relevant compounds, aromatic nitro compounds, aromatic ketones as well as aromatic aldehydes. The activity and chemoselectivity of the Ir NPs could be obviously impacted or adjusted by altering the modifier, solvent and reaction temperature.

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Selective Hydrogenation of Nitroaromatics by Colloidal Iridium Nanoparticles

Cited by 23 publications

References 26 publications

Structural Evolution of Iridium Oxide Cluster Anions Ir_nO_m^– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

Structural Evolution of Iridium Oxide Cluster Anions Ir_nO_m^– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir₁₋_xRh_xSb Intermetallic Alloy for Hydrogen Evolution Reaction

Selective hydrogenation of aromatic compounds using modified iridium nanoparticles

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Selective Hydrogenation of Nitroaromatics by Colloidal Iridium Nanoparticles

Cited by 23 publications

References 26 publications

Structural Evolution of Iridium Oxide Cluster Anions IrnOm– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

Structural Evolution of Iridium Oxide Cluster Anions IrnOm– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir1−xRhxSb Intermetallic Alloy for Hydrogen Evolution Reaction

Selective hydrogenation of aromatic compounds using modified iridium nanoparticles

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Structural Evolution of Iridium Oxide Cluster Anions Ir_nO_m^– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

Structural Evolution of Iridium Oxide Cluster Anions Ir_nO_m^– (n = 5–8) with Sequential Oxidation: Binding Mode of O Atoms and Ir Framework

Realizing Negatively Charged Metal Atoms through Controllable d‐Electron Transfer in Ternary Ir₁₋_xRh_xSb Intermetallic Alloy for Hydrogen Evolution Reaction