The Chemistry of Trimethylamine on Ru(001) and O/Ru(001)

Bf, Hallac; Asscher, Micha

doi:10.1021/la700895r

Cited by 6 publications

(5 citation statements)

References 38 publications

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“…The experiment was designed to be similar to TDS/TPD, wherein the sample of interest is pre-exposed to a gas adsorbate and then heated in a controlled fashion while monitoring the partial pressures of the evolved molecular species by using, for example, a mass spectrometer 37, 38 . The main difference of TPTEM from TDS/TPD is that it can be used to monitor the relative concentration of the remaining adsorbates within the spot on the sample illuminated by the femtosecond laser.…”

Section: Resultsmentioning

confidence: 99%

Adsorption energy of oxygen molecules on graphene and two-dimensional tungsten disulfide

Bagsican

Winchester

Ghosh

et al. 2017

Sci Rep

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Adsorption of gas molecules on the surface of atomically layered two-dimensional (2D) materials, including graphene and transition metal dichalcogenides, can significantly affect their electrical and optical properties. Therefore, a microscopic and quantitative understanding of the mechanism and dynamics of molecular adsorption and desorption has to be achieved in order to advance device applications based on these materials. However, recent theoretical calculations have yielded contradictory results, particularly on the magnitude of the adsorption energy. Here, we have experimentally determined the adsorption energy of oxygen molecules on graphene and 2D tungsten disulfide using temperature-programmed terahertz (THz) emission microscopy (TPTEM). The temperature dependence of THz emission from InP surfaces covered with 2D materials reflects the change in oxygen concentration due to thermal desorption, which we used to estimate the adsorption energy of oxygen molecules on graphene (~0.15 eV) and tungsten disulphide (~0.24 eV). Furthermore, we used TPTEM to visualize relative changes in the spatial distribution of oxygen molecules on monolayer graphene during adsorption and desorption. Our results provide much insight into the mechanism of molecular adsorption on the surface of 2D materials, while introducing TPTEM as a novel and powerful tool for molecular surface science.The successful isolation of monolayer graphene in 2004 and its remarkable properties found subsequently have paved the way for a new research field of two-dimensional (2D) atomic layer materials [1][2][3][4] . Many other 2D materials have since been discovered with a wide range of characteristics, from metallic to semiconducting to insulating, opening up exciting new opportunities for the development of devices based on monolayers, bilayers, and heterostructures of 2D materials [5][6][7][8] . However, since these materials typically consist of one or a few atomic layers, their properties are extremely susceptible to perturbations from their environment. Exposure to gases, for example, has been shown to drastically affect their electrical and optical properties [9][10][11][12][13][14][15] , which means that in order to realize 2D-materials-based devices, it is crucial to understand and control the influence of gas adsorption and desorption dynamics on their properties.Of the possible gas adsorbates/contaminants, oxygen (O 2 ) is one of the most important because not only it significantly alters the properties through doping, it is also the second most abundant gas in the atmosphere and is therefore highly likely to affect the performance of devices in practical applications. Though theoretical simulations proved to be useful in understanding the interaction of O 2 molecules and/or O atoms with 2D materials, conflicting results for the adsorption energies were obtained due to the inability of the approximation functionals used to properly describe the dispersion forces [16][17][18][19][20][21][22][23] . Knowing the correct value of the adsorption ...

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Section: Resultsmentioning

confidence: 99%

Adsorption energy of oxygen molecules on graphene and two-dimensional tungsten disulfide

Bagsican

Winchester

Ghosh

et al. 2017

Sci Rep

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“…Molecular adsorption on the oxide surface will lead to a positive or negative Volta potential shift depending on the type of interaction. SKP has shown its usefulness in the characterization of dipole interfaces after deposition of self-assembled monolayers (SAM) on Au, Ru, and for all kinds of optoelectronic devices. ,– Furthermore, recent publications from Nazarov and Thierry , described the effect of coating chemistry on the Volta potential after application of several coatings on metallic substrates. But, until now the effect of the oxide surface conditions on the dipole layer formed after adsorption of organic molecules has not been discussed in literature.…”

Section: Introductionmentioning

confidence: 99%

Interface Dipoles Observed after Adsorption of Model Compounds on Iron Oxide Films: Effect of Organic Functionality and Oxide Surface Chemistry

et al. 2008

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In this article, the interface dipole formed after adsorption of model compounds on thin iron oxide films is studied by scanning Kelvin probe (SKP). Amine and amide molecules with the same organic functionalities as an epoxy/amide coating system and a carboxylic acid molecule representing a maleic anhydride grafted or copolymerized polyolefin polymer were used as adsorbants. First, the effect of the functionality type on the Volta potential of a thermally formed iron oxide was investigated. It was shown that after carboxylic acid adsorption, the surface potential shifted in positive direction, whereas the amine and amide molecules induced a negative potential shift. Second, the Volta potential shift after adsorption of the amine and amide molecules on oxides with different amounts of surface hydroxyls was studied. A changing overall dipole moment as a function of the hydroxyl amounts was observed. Lewis acid-base interactions and protonation took place between the amine or amide functionality and the oxide surface. It was found that the Volta potential shift was mainly affected by the number of protonated amine or amide molecules. The individual interface dipole moments of the two binding types could be deduced from the Volta potential shift, assuming that the individual dipole moments of the two binding types contributed linearly to the overall dipole moment. For the protonation reaction, an interface dipole of -1.28 and -1.54 D was observed for the respective amine and amide molecule, whereas for the Lewis acid-base interaction, a dipole of +0.10 and +0.14 D was found.

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“…3 The adsorption and reaction of aliphatic and aromatic amines has been investigated extensively due to the importance of the basic amine group to many heterogeneously catalyzed processes as reactants and products and as catalyst modifiers. [4][5][6] Previous surface chemical studies of amines have focused primarily on clean and/or oxygen-covered Ni, 3,7,8 Ru, 9 Pt, 10 W, 11 Cu, 5,12 Ag, 13,14 and Si 15 surfaces.…”

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confidence: 99%

Selective oxidation of propylamine to propionitrile and propionaldehyde on oxygen-covered gold

2009

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The Chemistry of Trimethylamine on Ru(001) and O/Ru(001)

Cited by 6 publications

References 38 publications

Adsorption energy of oxygen molecules on graphene and two-dimensional tungsten disulfide

Adsorption energy of oxygen molecules on graphene and two-dimensional tungsten disulfide

Interface Dipoles Observed after Adsorption of Model Compounds on Iron Oxide Films: Effect of Organic Functionality and Oxide Surface Chemistry

Selective oxidation of propylamine to propionitrile and propionaldehyde on oxygen-covered gold

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