Promoting effect of Pt in Ni-based catalysts for CH4 reforming

Arishtirova, K.; Pawelec, B.; Николов, Р.Н.; Fierro, J.L.G.; Damyanova, S.

doi:10.1007/s11144-007-5139-8

Cited by 15 publications

(8 citation statements)

References 14 publications

(10 reference statements)

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“…Recently, bimetallic catalysts have been shown exhibit higher activity and/or selectivity for various catalytic reactions than the pure metal catalysts . It has also been suggested that the addition of noble metals to a Ni catalyst may reduce coke deposition and therefore provide better stability . Based on combined DFT, surface science and advanced characterization, Besenbacher et al .…”

Section: Introductionmentioning

confidence: 98%

“…Production of hydrogen from natural gas offers many advantages among all potential sources. Steam reforming, dry reforming, partial oxidation and autothermal reforming of methane have been known as main processes used to produce hydrogen from natural gas . Supported Ni catalysts are widely used for catalytic reforming of methane for hydrogen production in industrial processes due to their low price and high activity.…”

Section: Introductionmentioning

confidence: 99%

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Methane Activation on Bimetallic Catalysts: Properties and Functions of Surface Ni−Ag Alloy

et al. 2019

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The paper presents a fundamental study of the properties and functions of well-defined NiÀ Ag surface alloys in methane decomposition and steam reforming, aiming at providing a better understanding of the principle for manipulating the catalytic activity of steam reforming and suppressing carbon formation. A better insight of structure-property relationship was obtained by a kinetic study of the reactions on well-defined surface NiÀ Ag alloys, which were synthesized by surface redox reaction to selectively introduce Ag atoms into the surface of Ni particles supported on hydrotalcite derived support. The effects of Ni surface alloy with Ag are three-folds in general. Replacement of Ni by Ag reduces the number of active site exponentially with increasing Ag site coverage. Ag site is not only inactive, but also significantly reduces the activity of adjacent Ni sites for methane activation in both methane decomposition and steam reforming. The third effect is to block the active sites for the nucleation and growth of the filamentous carbon. The rate of methane activation at Ni step sites was found to be 16-19 times of that on Ni terrace sites. The carbon formation rate decreased linearly with Ag site coverage and the effect of Ag is divided into two regions. At low Ag site coverages (0 to 0.055), Ag atoms preferentially deposit on Ni step sites, which has a significant effect on the methane activation compared to Ag atoms on the Ni terrace sites. The results reveal that the effects of Ag site on the carbon formation in the two regions are mostly caused by the different effects of Ag on the activity of Ni step sites and terrace sites, respectively, rather than the different ensemble sizes for carbon formation proposed in the literature.[a] Dr.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Methane Activation on Bimetallic Catalysts: Properties and Functions of Surface Ni−Ag Alloy

et al. 2019

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“…Since Pt precursors can be reduced by H 2 more easily than precursors of 3d TMs, the initial structural configuration of Pt-3d-TM catalysts prepared by the co-impregnation and co-reduction process should be Pt NPs decorated by 3d-TM overlayers. 77 On the other hand, inward diffusion of surface 3d-TMs into the subsurface or even bulk regions of Pt crystals may happen upon heating in UHV or reductive atmospheres ( Figure S2). 10,56,60,62,78,79 Accordingly, the surface structure of the PtNi/CB catalysts can be simply controlled by reduction in H 2 .…”

Section: ' Introductionmentioning

confidence: 99%

Synergetic Effect of Surface and Subsurface Ni Species at Pt−Ni Bimetallic Catalysts for CO Oxidation

et al. 2011

J. Am. Chem. Soc.

267

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Various well-defined Ni-Pt(111) model catalysts are constructed at atomiclevel precision under ultra-high-vacuum conditions and characterized by X-ray photoelectron spectroscopy and scanning tunneling microscopy. Subsequent studies of CO oxidation over the surfaces show that a sandwich surface (NiO 1-x /Pt/Ni/Pt(111)) consisting of both surface Ni oxide nanoislands and subsurface Ni atoms at a Pt(111) surface presents the highest reactivity. A similar sandwich structure has been obtained in supported Pt-Ni nanoparticles via activation in H 2 at an intermediate temperature and established by techniques including acid leaching, inductively coupled plasma, and X-ray adsorption nearedge structure. Among the supported Pt-Ni catalysts studied, the sandwich bimetallic catalysts demonstrate the highest activity to CO oxidation, where 100% CO conversion occurs near room temperature. Both surface science studies of model catalysts and catalytic reaction experiments on supported catalysts illustrate the synergetic effect of the surface and subsurface Ni species on the CO oxidation, in which the surface Ni oxide nanoislands activate O 2 , producing atomic O species, while the subsurface Ni atoms further enhance the elementary reaction of CO oxidation with O.

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“…Thus, significant efforts have been made to improve Ni-based catalysts to prevent coking in reforming reactions, and detailed investigation of the reaction mechanisms can aid design of novel catalysts and optimization of reaction conditions. Recent research showed that introducing small amounts of precious metals into Ni-based catalysts could effectively reduce coking and enhance catalyst activity and stability [6,11,12,[22][23][24][25][26][27][28][29][30][31][32][33][34]. For instance, Besenbacher et al [22] and Molenbroek et al [23] found that the addition of a small amount of Au into the Ni catalyst (hereafter termed Au/Ni) can effectively reduce coking.…”

Section: Introductionmentioning

confidence: 99%