Composite Materials with Combined Electronic and Ionic Properties

Ralbag, Noam; Mann‐Lahav, Meirav; Davydova, Elena S.; Ash, Uri; Galed, Reuven; Handl, Michael; Hiesgen, Renate; Magliocca, Emanuele; Mustain, William E.; He, Jin; Cong, Peixi; Beale, Andrew M.; Grader, Gideon S.; Dekel, Dario R.

doi:10.1016/j.matt.2019.04.007

Cited by 37 publications

(30 citation statements)

References 85 publications

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“…The materials methodology of molecular doping of metals employed herein involves a variety of reducing processes of metal cations in the presence of the molecule or nanoparticle (NP) to be entrapped (see refs. for reviews and for recent examples). The resulting material is the metal in the form of tightly agglomerated nanometric crystals, incorporating the dopant molecule or NPs.…”

Section: Introductionmentioning

confidence: 99%

“…[9][10][11] Them aterials methodology of molecular doping of metals employed herein involves av ariety of reducing processes of metal cations in the presence of the molecule or nanoparticle (NP) to be entrapped (see refs. [12,13] for reviews and [11,14,18] for recent examples). Ther esulting material is the metal in the form of tightly agglomerated nanometric crystals,incorporating the dopant molecule or NPs.The dopant is firmly held by the physical caging and by interactions between its functional moieties and the metallic surface of the nanocrystals that form the cages.I th as been repeatedly shown, in previous applications studies of this materials methodology,t hat this 3D architecture is completely different from regular 2D adsorption, and various specific applications,s uch as in catalysis, [17] biomaterials, [15,16] fuel cell, [14] and more, [18] are achieved only with the 3D entrapment.…”

Section: Introductionmentioning

confidence: 99%

“…[12,13] for reviews and [11,14,18] for recent examples). Ther esulting material is the metal in the form of tightly agglomerated nanometric crystals,incorporating the dopant molecule or NPs.The dopant is firmly held by the physical caging and by interactions between its functional moieties and the metallic surface of the nanocrystals that form the cages.I th as been repeatedly shown, in previous applications studies of this materials methodology,t hat this 3D architecture is completely different from regular 2D adsorption, and various specific applications,s uch as in catalysis, [17] biomaterials, [15,16] fuel cell, [14] and more, [18] are achieved only with the 3D entrapment. This is so because unlike 2D adsorption where the molecules interact with the metal typically through one moiety,i n3 De ntrapment the interaction between the dopant and the molecule is through all of its parts,t herefore,t he effect of the electrons ocean of the metal on the dopant and of the dopants orbitals on the metal, is different and significantly stronger.…”

Section: Introductionmentioning

confidence: 99%

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Affecting an Ultra‐High Work Function of Silver

Armstrong

Cong

et al. 2020

Angew Chem Int Ed

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An ultra‐high increase in the WF of silver, from 4.26 to 7.42 eV, that is, an increase of up to circa 3.1 eV is reported. This is the highest WF increase on record for metals and is supported by recent computational studies which predict the potential ability to affect an increase of the WF of metals by more than 4 eV. We achieved the ultra‐high increase by a new approach: Rather than using the common method of 2D adsorption of polar molecules layers on the metal surface, WF modifying components, l‐cysteine and Zn(OH)2, were incorporated within the metal, resulting in a 3D architecture. Detailed material characterization by a large array of analytical methods was carried out, the combination of which points to a WF enhancement mechanism which is based on directly affecting the charge transfer ability of the metal separately by cysteine and hydrolyzed zinc(II), and synergistically by the combination of the two through the known Zn‐cysteine finger redox trap effect.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Affecting an Ultra‐High Work Function of Silver

Armstrong

Cong

et al. 2020

Angew Chem Int Ed

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“…In order to improve the ion conduction of the catalyst surface, Ralbag et al. used ionomers to dope silver metal catalysts at the molecular level to obtain composite materials with both electrocatalytic and ionic properties [3] . In addition, ionomer crosslinking immobilization, [4] nanodispersed ionomer [5] or ionic liquid modification [6] were employed to improve the microenvironment of Pt catalysts to prepare high‐performance alkaline membrane fuel cell catalyst layers.…”

Section: Figurementioning

confidence: 99%

Reshaping the Cathodic Catalyst Layer for Anion Exchange Membrane Fuel Cells: From Heterogeneous Catalysis to Homogeneous Catalysis

et al. 2020

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In anion exchange membrane fuel cells, catalytic reactions occur at a well‐defined three‐phase interface, wherein conventional heterogeneous catalyst layer structures exacerbate problems, such as low catalyst utilization and limited mass transfer. We developed a structural engineering strategy to immobilize a molecular catalyst tetrakis(4‐methoxyphenyl)porphyrin cobalt(II) (TMPPCo) on the side chains of an ionomer (polyfluorene, PF) to obtain a composite material (PF‐TMPPCo), thereby achieving a homogeneous catalysis environment inside ion‐flow channels, with greatly improved mass transfer and turnover frequency as a result of 100 % utilization of the catalyst molecules. The unique structure of the homogeneous catalysis system comprising interconnected nanoreactors exhibits advantages of low overpotential and high fuel‐cell power density. This strategy of reshaping of the catalyst layer structure may serve as a new platform for applications of many molecular catalysts in fuel cells.

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“…The possibility of exploring this direction has emerged from the intensive development of the materials methodology of molecular doping of metals. 23,24 A wide variety of molecules including organometallic complexes, 25 drug molecules, 26 dyes, 27 polymers, 28 nanoparticles 29 and more 30 have been incorporated into various metals, including copper, silver, gold, platinum, gallium and more. The resulting molecule@metal materials have been utilized for a host of activities ranging from catalysis to drug release, and in many instances synergistic and improved activities were recorded.…”

Section: Introductionmentioning

confidence: 99%

Enzymes in a golden cage

Baruch-Shpigler

Avnir

2020

Chem. Sci.

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We describe a general method for the entrapment of enzymes within bulk metallic gold. This is a new approach for the immobilization of enzymes on metals, which is commonly carried out by 2D adsorption or covalent biding, that is, the enzyme is in contact with the metal at a specific contact zone of the enzyme, while most of the rest of it remains exposed to the environment. The 3D metallic encaging of the enzymes is quite different: the enzyme is in contact with the metallic cage walls all around it and is well protected inside. The porous nature of the metallic matrix enables substrate molecules to diffuse inside, reach the active site, and let product molecules diffuse out. The generality of the approach was proven by the successful entrapment of five enzymes representing different classes and different bioand medical applications: L-asparaginase (Asp), collagenase, horseradish peroxidase (HRP), laccase and glucose oxidase (GOx). GOx-gold conjugates have been of particular interest in the literature. The main challenge we had to solve was how to keep the enzyme active in the process of gold-synthesis from its cationthis required careful tailoring of reaction conditions, which are detailed in the paper. The gold entrapped enzymes gain thermal stability and protectability against harsh conditions. For instance, we could keep Asp alive at the extreme pH of 13, which normally kills the enzyme instantly. The entrapped enzymes obey the Michaelis-Menten kinetics, and activation energies were determined. Good recyclability for eight cycles was found. Multi-enzymatic reactions by combinations of the off-the-shelf bioactive enzyme@gold powders are possible, as demonstrated for the classical detection of GOx activity with HRP. Detailed material characterization and proposed mechanisms for the 3D protectability of the enzymes are provided. The new enzyme immobilization method is of wide potential uses in medicine, biotechnology, bio-fuel cells and enzymatic (electro)sensing applications.Scheme 1 (Top) Entrapped enzyme (glucose oxidase, GOx) within a golden cage. In redthe surface amino acids of GOx which contain gold binding moieties (thiols, amines, imines and carboxylate anions, taken from PDB file 1CF3). (Bottom) The entrapment processsee also Scheme 2. Scheme 2The mechanism of entrapmentsee text for details. Bottom: 2D adsorption, a completely different architecture compared with the 3D entrapment.This journal is

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Composite Materials with Combined Electronic and Ionic Properties

Cited by 37 publications

References 85 publications

Affecting an Ultra‐High Work Function of Silver

Affecting an Ultra‐High Work Function of Silver

Reshaping the Cathodic Catalyst Layer for Anion Exchange Membrane Fuel Cells: From Heterogeneous Catalysis to Homogeneous Catalysis

Enzymes in a golden cage

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