Surface structure of an ionic liquid with high-resolution Rutherford backscattering spectroscopy

Nakajima, K.; Ohno, Atsushi; Suzuki, Motofumi; Kimura, Kenji

doi:10.1016/j.nimb.2008.11.020

Cited by 22 publications

(24 citation statements)

References 23 publications

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“…Many established UHV-based surface science techniques have successfully contributed to an increasingly detailed understanding not only of the IL/ vacuum interface, but also of IL bulk properties. The applied methods include X-ray photoelectron spectroscopy (XPS) [106,107,, UV photoelectron spectroscopy [138,139,165,166], inverse photoelectron spectroscopy (IPES) [165,166], X-ray absorption spectroscopy (NEXAFS) [165], soft X-ray emission spectroscopy (SXES) [166], low energy ion scattering (LEIS) [141], metastable ion spectroscopy (MIES) [138,139], time-offlight secondary mass spectroscopy (TOF-SIMS) [140], Rutherford backscattering [167][168][169][170][171], high resolution electron energy loss spectroscopy (HREELS) [138], reflection absorption infrared spectroscopy (RAIRS) [172][173][174][175], direct recoil spectroscopy (DRS) [176], and scanning tunneling microscopy [177][178][179][180][181], to name only a few. In addition, an increasing number of theoretical studies and simulations have been conducted [101,[182][183][184][185][186][187][188][189][190].…”

Section: Molecular Insights Into Il/gas and Il/support Interfacesmentioning

confidence: 99%

Ionic Liquids in Catalysis

2014

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Ionic liquids (ILs), salts with melting points below 100°C, represent a fascinating class of liquid materials typically characterized by an extremely low vapor pressure. Besides their application as new solvents or as electrolytes for electrochemical purposes, there are two important concepts of using ILs in catalysis: Liquid-liquid biphasic catalysis and IL thin film catalysis. Liquid-liquid biphasic catalysis enables either a very efficient manner to apply catalytic ILs, e.g. in Friedel-Crafts reactions, or to apply ionic transition metal catalyst solutions. In both cases, phase separation after reaction allows an easy separation of reaction products and catalyst re-use. One problem of liquidliquid biphasic catalysis is mass transfer limitation. If the chemical reaction is much faster than the liquid-liquid mass transfer the latter limits the overall reaction rate. This problem is overcome in IL thin film catalysis where diffusion pathways and thus the characteristic time of diffusion are short. Here, Supported Ionic Liquid Phase (SILP) and Solid Catalyst with Ionic Liquid Layer (SCILL) are the two most important concepts. In both, a high surface area solid substrate is covered with a thin IL film, which contains either a homogeneously dissolved transition metal complex for SILP, or which modifies catalytically active surface sites at the support for SCILL. In each concept, interface phenomena play a very important role: These may concern the interface of an IL phase with an organic phase in the case of liquidliquid biphasic catalysis. For IL thin film catalysis, the interfaces of the IL with the gas phase and with catalytic nanoparticles and/or support materials are of critical importance. It has recently been demonstrated that these interfaces and also the bulk of ILs can be investigated in great detail using surface science studies, which greatly contributed to the fundamental understanding of the catalytic properties of ILs and supported IL materials. Exemplary results concerning the IL/vacuum or IL/gas interface, the solubility and surface enrichment of dissolved metal complexes, the IL/support interface and the in situ monitoring of chemical reactions in ILs are presented.

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Section: Molecular Insights Into Il/gas and Il/support Interfacesmentioning

confidence: 99%

Ionic Liquids in Catalysis

2014

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“…Owing to the very low vapor pressure of ILs,15 spectroscopic surface science techniques—formerly only applied to study solid surfaces—can be adopted to investigate IL surfaces. Examples include direct recoil spectroscopy (DRS),14a,b high‐resolution electron energy loss spectroscopy (HREELS),16 low‐energy ion scattering (LEIS),17 Rutherford back‐scattering,18 X‐ray and neutron reflectometry,19 and grazing incidence X‐ray diffraction 20…”

Section: Maximum Solubility Of [Rh(acac)(co)2] and Tppts In Various Imentioning

confidence: 99%

Ligand Effects on the Surface Composition of Rh‐Containing Ionic Liquid Solutions Used in Hydroformylation Catalysis

Kolbeck¹,

Paape²,

Cremer³

et al. 2010

Chemistry A European J

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The molecular design of nanoporous membranes with desired morphology and selectivity has attracted significant interest over the past few decades. A major problem in their applications is the trade‐off between sieving property and permeability. Here, we report the discovery of elongation‐induced nano‐pore evolution during the external stretching of a novel polyamide‐imide nanofiltration hollow fiber membrane in a dry‐jet wet‐spinning process that simultaneously leads to a decreased pore size but increased pure water permeability. The molecular weight cutoff, pore size, and pore size distribution were finely tuned using this approach. AFM and polarized FTIR verified the nano‐pore morphological evolution and an enhanced molecular orientation in the surface skin layer. The resultant nanofiltration membranes exhibit highly effective fractionation of the monovalent and divalent ions of NaCl/Na2SO4 binary salt solutions. More than 99.5% glutathione can be rejected by the nanofiltration membranes at neutral pH, offering the feasibility of recovering this tripeptide. © 2009 American Institute of Chemical Engineers AIChE J, 2010

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“…Recent work by several groups [30][31][32][33][34][35][36][37][38][39][40][41][42][43] including those of the authors [44][45][46][47][48][49][50][51][52][53][54][55][56][57] shows that a rigorous surface science approach can indeed be applied to IL surfaces and interfaces. There are mainly two aspects, which make such studies possible: First, the vapor pressure of many aprotic ILs is suffi ciently low so that their surfaces can be straightforwardly studied under ultrahigh vacuum (UHV) conditions.…”

Section: Introductionmentioning

confidence: 99%

Surface Science and Model Catalysis with Ionic Liquid‐Modified Materials

et al. 2011

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Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy.

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Surface structure of an ionic liquid with high-resolution Rutherford backscattering spectroscopy

Cited by 22 publications

References 23 publications

Ionic Liquids in Catalysis

Ionic Liquids in Catalysis

Ligand Effects on the Surface Composition of Rh‐Containing Ionic Liquid Solutions Used in Hydroformylation Catalysis

Surface Science and Model Catalysis with Ionic Liquid‐Modified Materials

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