Ionic Liquid-Modified Electrocatalysts: The Interaction of [C 1 C 2 Im][OTf] with Pt(1 1 1) and its Influence on Methanol Oxidation Studied by Electrochemical IR Spectroscopy

Brummel, Olaf; Faisal, Firas; Bauer, Tanja; Põhako‐Esko, Kaija; Wasserscheid, Peter; Libuda, Jörg

doi:10.1016/j.electacta.2015.12.006

Cited by 38 publications

(36 citation statements)

References 77 publications

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“…In the direct pathway methanol is oxidized to CO 2 via partially oxidized intermediates, while in the indirect pathway adsorbed CO (CO ads ) is formed as an intermediate, which poisons the catalyst. In this study we use this CO ads as a spectroscopic probe molecule to monitor changes in Pt particle size and structure …”

Section: Resultsmentioning

confidence: 99%

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

et al. 2016

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Pt-doped CeO x thin film electrocatalysts have recently been shown to exhibit high activity and stability at the anode of proton exchange membrane fuel cells (PEM-FC). To identify the role of the Pt dopant and the origin of the high stability of Pt–CeO x films, we applied electrochemical in situ IR spectroscopy on Pt–CeO x model thin film catalysts during methanol (1 M methanol) oxidation. The model catalysts were prepared by magnetron cosputtering of Pt (9–21 atom %) and CeO2 onto clean and carbon-coated Au supports. All samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) before and after reaction. At pH 1 (0.1 M HClO4) the Pt–CeO x dissolves partially during potential cycling, whereas the films are largely stable at pH 6 (0.1 M phosphate buffer). Electrochemical IR spectroscopy of the adsorbed CO shows that metallic Pt is formed on all Pt–CeO x samples during methanol oxidation. In comparison to Pt(111), Pt aggregates on Pt–CeO x show a CO on-top signal, which is red shifted by at least 25 cm–1 and suppression of the bridging CO signals. Whereas the Pt particles on Pt–CeO x films with high Pt concentration (>20 atom %) undergo rapid sintering during the potential cycling, small metallic Pt aggregates are stable under the same conditions on films with low Pt concentration (<15 atom % Pt). By means of density functional theory (DFT) calculations we analyzed the spectral shifts of adsorbed CO as a function of nanoparticle size both on free and ceria-supported Pt particles. Comparison with the experiment suggests the formation of “subnano”-particles, i.e., particles with up to 30 atoms (<1 nm particle diameter), which do not expose regular (111) facet sites. At sufficiently low Pt loading, these subnano-Pt particles are efficiently stabilized by the interaction with the ceria support under conditions of the dynamically changing electrode potential.

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Section: Resultsmentioning

confidence: 99%

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

et al. 2016

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“…[26][27][28] The structural dynamics of EDL formation was studied by XPS using two gold electrodes fabricated on a porous polymer surface. 29 The adsorption geometry and the reorientation of ILs in response to the applied potential have also been investigated experimentally using sum frequency generation, 30 infrared spectroscopy, 31 surfaceenhanced Raman spectroscopy, 32 scanning tunneling microscopy, 33,34 and X-ray photoelectron spectroscopy (XPS) through an ultrathin graphene-carbon nanotube composite window, 35 together with computational methods. 28,36 The chemical interaction between the electrode and ions in ILs, which is denoted as specific adsorption in electrochemistry, also plays an important role for the EDL structure of ILs.…”

Section: Introductionmentioning

confidence: 99%

Enrichment effects of ionic liquid mixtures at polarized electrode interfaces monitored by potential screening

Shin

Greco

Maier

et al. 2021

Phys. Chem. Chem. Phys.

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“…Besides application in classic solid state chemistry, ILs can be used as reaction media to prepare (oligomeric) metal complexes, metal organic frameworks, coordination polymers [25–35] or cluster compounds incorporating main group elements [36–41] . Within SPP 1708, the synthesis of intermetallic cluster and nanoparticles, [3,42–56] the controlled synthesis of polyanions and cations, [57–61] solvent‐free chalcogenidometal‐containing materials, [62–75] deposition of nanocrystalline materials, [76–80] ionic liquids as precursors for inorganic materials, [81–83] ionic‐liquid‐modified hybrid materials, [84–87] as well as the low‐temperature synthesis of thermoelectric materials [88–92] were investigated. Moreover, theoretical [93–106] and solubility [107–114] aspects during the synthesis process were studied.…”

Section: Introductionmentioning

confidence: 99%

Pseudohalogen Chemistry in Ionic Liquids with Non‐innocent Cations and Anions

et al. 2020

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Within the second funding period of the SPP 1708 “Material Synthesis near Room Temperature”,which started in 2017, we were able to synthesize novel anionic species utilizing Ionic Liquids (ILs) both, as reaction media and reactant. ILs, bearing the decomposable and non‐innocent methyl carbonate anion [CO3Me]−, served as starting material and enabled facile access to pseudohalide salts by reaction with Me3Si−X (X=CN, N3, OCN, SCN). Starting with the synthesized Room temperature Ionic Liquid (RT‐IL) [nBu3MeN][B(OMe)3(CN)], we were able to crystallize the double salt [nBu3MeN]2[B(OMe)3(CN)](CN). Furthermore, we studied the reaction of [WCC]SCN and [WCC]CN (WCC=weakly coordinating cation) with their corresponding protic acids HX (X=SCN, CN), which resulted in formation of [H(NCS)2]− and the temperature labile solvate anions [CN(HCN)n]− (n=2, 3). In addition, the highly labile anionic HCN solvates were obtained from [PPN]X ([PPN]=μ‐nitridobis(triphenylphosphonium), X=N3, OCN, SCN and OCP) and HCN. Crystals of [PPN][X(HCN)3] (X=N3, OCN) and [PPN][SCN(HCN)2] were obtained when the crystallization was carried out at low temperatures. Interestingly, reaction of [PPN]OCP with HCN was noticed, which led to the formation of [P(CN)2]−, crystallizing as HCN disolvate [PPN][P(CN⋅HCN)2]. Furthermore, we were able to isolate the novel cyanido(halido) silicate dianions of the type [SiCl0.78(CN)5.22]2− and [SiF(CN)5]2− and the hexa‐substituted [Si(CN)6]2− by temperature controlled halide/cyanide exchange reactions. By facile neutralization reactions with the non‐innocent cation of [Et3HN]2[Si(CN)6] with MOH (M=Li, K), Li2[Si(CN)6] ⋅ 2 H2O and K2[Si(CN)6] were obtained, which form three dimensional coordination polymers. From salt metathesis processes of M2[Si(CN)6] with different imidazolium bromides, we were able to isolate new imidazolium salts and the ionic liquid [BMIm]2[Si(CN)6]. When reacting [Mes(nBu)Im]2[Si(CN)6] with an excess of the strong Lewis acid B(C6F5)3, the voluminous adduct anion {Si[CN⋅B(C6F5)3]6}2− was obtained.

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Ionic Liquid-Modified Electrocatalysts: The Interaction of [C 1 C 2 Im][OTf] with Pt(1 1 1) and its Influence on Methanol Oxidation Studied by Electrochemical IR Spectroscopy

Cited by 38 publications

References 77 publications

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

Enrichment effects of ionic liquid mixtures at polarized electrode interfaces monitored by potential screening

Pseudohalogen Chemistry in Ionic Liquids with Non‐innocent Cations and Anions

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Ionic Liquid-Modified Electrocatalysts: The Interaction of [C 1 C 2 Im][OTf] with Pt(1 1 1) and its Influence on Methanol Oxidation Studied by Electrochemical IR Spectroscopy

Cited by 38 publications

References 77 publications

Stabilization of Small Platinum Nanoparticles on Pt–CeO2Thin Film Electrocatalysts During Methanol Oxidation

Stabilization of Small Platinum Nanoparticles on Pt–CeO2Thin Film Electrocatalysts During Methanol Oxidation

Enrichment effects of ionic liquid mixtures at polarized electrode interfaces monitored by potential screening

Pseudohalogen Chemistry in Ionic Liquids with Non‐innocent Cations and Anions

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Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation

Stabilization of Small Platinum Nanoparticles on Pt–CeO₂Thin Film Electrocatalysts During Methanol Oxidation