Adsorption of tetralin and hydrogenated intermediates and products on the (100) surfaces of Ir, Pt and Pd: a DFT study

Li, Xiang; Wong, Madaliene S. M.; Lim, Kok Hwa

doi:10.1007/s00214-010-0728-4

Cited by 10 publications

(6 citation statements)

References 64 publications

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“…Our current DFT calculations show that the BEs of atomic H adsorbing on Pt (100) surface at atop, bridge and hollow sites are -2.71, -2.90 and -2.51 eV, respectively, with the bridge site as the most favorable site. This is because the (100) surface is more open compared to the (111) surface and hence hollow site interacts less effectively with the H atom as the H-Pt bonds are longer compared to (111) surface [37,42].…”

Section: Atomic Hydrogen (H)mentioning

confidence: 94%

A DFT Study on the Adsorption of Formic Acid and Its Oxidized Intermediates on (100) Facets of Pt, Au, Monolayer and Decorated Pt@Au Surfaces

Wang

Lim

2011

Catal Lett

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In this work we have systematically characterized the adsorption of formic acid, its decomposed intermediates and products on the (100) surfaces of Pt, Au, monolayer and decorated Pt@Au surfaces. The calculated thermodynamic results validate our previous experimental results that the decorated Pt@Au surface may facilitate formic acid oxidation compared with the benchmark Pt catalyst; while the monolayer Pt@Au surface is not suitable for formic acid oxidation.

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Section: Atomic Hydrogen (H)mentioning

confidence: 94%

A DFT Study on the Adsorption of Formic Acid and Its Oxidized Intermediates on (100) Facets of Pt, Au, Monolayer and Decorated Pt@Au Surfaces

Wang

Lim

2011

Catal Lett

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“…The calculated much lower energy barrier on the Pt(1 1 1) surface for the hydrogenation of MCONE than on the Pd(1 1 1) surface is in agreement with the experimental observation herein that on the Pt/HY [50][51][52] indicate that the free energy barrier for hydrogenation of C@O bonds is higher (i.e., lower rates) on Pd than on Pt surfaces. The lower activity of Pd has been usually linked to the stronger interactions of O with Pd than with Pt [53][54][55]. The stronger interaction of the reactant with the catalyst surface leading to lower rates indicates that Pt, on the activity volcano plot, is closer than Pd to the optimum MAO strength that maximizes hydrogenation.…”

Section: Hydrogenation Of 3-methylcyclohexanone and 3-methylcyclohexementioning

confidence: 96%

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Anaya

Zhang

Tan

et al. 2015

Journal of Catalysis

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a b s t r a c tThe liquid-phase hydroalkylation of m-cresol catalyzed by zeolite catalysts doped with noble metals was investigated at 473 K and 5200 kPa of H 2 . Metals (Pt and Pd) were incorporated in HY (Si/Al = 30) and HMor (Si/Al = 10) zeolites by incipient wetness impregnation. The structural properties of the samples were characterized by NMR, XPS, and BET. Hydroalkylation of m-cresol involves a series of steps that start with the ring saturation to 3-methylcyclohexanone (MCONE), which is the primary product and is further hydrogenated to methylcyclohexanol (MCNOL) on the metal function. This, in turn, is dehydrated on the acid sites to 3-methylcyclohexene, which readily alkylates the unreacted m-cresol to form bicyclic compounds that fall in the desirable fuel range. In these bifunctional catalysts, differences in intrinsic hydrogenation activity of metals play an important role in determining the final selectivity to alkylated products. In fact, the ratio of number of acid sites (n A ) to exposed metal sites (n M ) can be tuned to maximize the selectivity toward bicyclic compounds because this selectivity is determined by the fate of the intermediate 3-methylcyclohexene (MCENE). That is, if the C@C hydrogenation on the metal is fast compared to alkylation on the acid site, the selectivity decreases. However, if the hydrogenation is too slow, the overall product yield decreases. Thus, to optimize the hydroalkylation yield, a delicate metal/acid balance is required. Moreover, in the absence of metal, the zeolite would deactivate very quickly. Therefore, having the metal and acid functions together is also important for extending the catalyst life. Finally, it has been observed that 3D-pore zeolites, such as HY, are preferred over 1D-pore zeolites such as HMor, which sharply diminish the formation of alkylation compounds, despite being more acidic than HY.

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“…The three bridge sites (A, B, and C) and the top site are discarded as possible adsorption sites since they are more than 70 kJ mol –1 less stable than the hollow sites. Larger adsorption energies have been calculated for hollowB benzene on Pd(100) with periodic DFT calculations by Li et al (−208 kJ mol –1 ) and Orita et al (−196 kJ mol –1 ) but for much lower coverage (1/4 and 1/3 of the experimental saturation coverage, respectively). The same relative ordering in stability of the three types of sites was found in a DFT study of the Ni(100) case by Mittendorfer and Hafner .…”

Section: Benzene Adsorption On Pd(100) At Medium and Saturation Coveragementioning

confidence: 99%

“…Insights into the interaction of benzene with the different Pd surfaces can help to understand and improve the behavior of Pd nanosized catalysts. Benzene adsorption on various Pd surfaces has been studied extensively using a variety of surface analytical techniques, including low-energy electron diffraction (LEED), − near-edge X-ray absorption fine structure spectroscopy (NEXAFS), , thermal desorption spectroscopy (TPD), ,,− electron energy loss spectroscopy (EELS), ,,,,− scanning tunneling microscopy (STM), ,,, and ultraviolet photoemission spectroscopy (UPS). ,,,− In addition, benzene adsorption on various transition metals has been studied using theoretical techniques such as periodic density functional theory (DFT). ,− …”

Section: Introductionmentioning

confidence: 99%

Periodic DFT Study of Benzene Adsorption on Pd(100) and Pd(110) at Medium and Saturation Coverage

et al. 2014

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Benzene adsorption on Pd(100) and Pd(110) has been investigated using periodic density functional theory (DFT) calculations. 4-Fold hollow geometries are preferentially adopted on both surfaces, and due to stronger repulsive interactions on Pd(100) a larger decrease in adsorption energy is calculated from medium to saturation coverage (∼120 kJ mol −1 ) compared to Pd(110) (∼15 kJ mol −1 ). On Pd(100), a slight energetic preference is calculated at saturation coverage for an adsorbate with two CC bonds parallel to the [011̅ ] direction. However, an adsorption geometry with alternately two types of benzene adsorbates, rotated azimuthally by 30°r elative to one another, cannot be discarded since both geometries are compatible with ultraviolet photoemission spectroscopy (UPS) and high-resolution electron energy loss spectroscopy (HREELS) observations. On Pd(110), there is a slight energetic preference for the hollow(0) site relative to the hollow(15) and hollow(30) at saturation coverage, and their calculated electronic features match UPS experiments. For the hollow(30), calculated vibrational features are not compatible with HREELS experiments, indicating that benzene does not populate hollow(30) sites at saturation coverage. Calculated STM images confirm that the experimentally observed two-lobed protrusion separated by a single depression oriented with its direction some 50°from [11̅ 0] can only correspond to the hollow(15) adsorbate. Inclusion of van der Waals interactions (vdW-DFT) increases adsorption energies by some 50 kJ mol −1 , but the relative ordering of the various adsorption sites remains unaltered as compared to PW91.

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Adsorption of tetralin and hydrogenated intermediates and products on the (100) surfaces of Ir, Pt and Pd: a DFT study

Cited by 10 publications

References 64 publications

A DFT Study on the Adsorption of Formic Acid and Its Oxidized Intermediates on (100) Facets of Pt, Au, Monolayer and Decorated Pt@Au Surfaces

A DFT Study on the Adsorption of Formic Acid and Its Oxidized Intermediates on (100) Facets of Pt, Au, Monolayer and Decorated Pt@Au Surfaces

Tuning the acid–metal balance in Pd/ and Pt/zeolite catalysts for the hydroalkylation of m-cresol

Periodic DFT Study of Benzene Adsorption on Pd(100) and Pd(110) at Medium and Saturation Coverage

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