Study of Pt–CeO2 interaction and the effect in the selective hydrodechlorination of trichloroethylene

Barrabés, Noelia; Föttinger, Karin; Dafinov, A.; Medina, Francisco; Rupprechter, Günther; Llorca, Jordi; Sueiras, J.E.

doi:10.1016/j.apcatb.2008.08.018

Cited by 54 publications

(46 citation statements)

References 32 publications

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“…Recently, for a ceria-supported catalyst a band in this region was assigned to an interfacial Pt-CO-Ce 3+ species. [31] In an experiment without oxygen (exposure to pure CO), the intensity of this peak increased over time, while the signal for gas-phase CO 2 decreased (see Figure S5), indicating that even in the absence of O 2 , small amounts of CO can be oxidized presumably by a Mars-van Krevelen-like mechanism [20] by means of oxygen from the support.…”

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confidence: 89%

Ligand Capping of Colloidally Synthesized Nanoparticles—A Way to Tune Metal–Support Interactions in Heterogeneous Gas‐Phase Catalysis

et al. 2011

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Catalysis by noble metals is still extremely important for the industrial production of chemicals, [1] in catalytic converters, [2] and in new areas of energy generation (e.g. fuel cells [3] ) and storage (e.g. batteries [4] ). Since the supplies of these metals are limited and their prices continuously increase, the search for new classes of catalytic materials, such as cheap and abundant oxides, [5] and significant improvement of the performance of existing metal catalyst systems is indispensable.An attractive option in this context is the use of the support as a co-catalyst; in other words, shifting the main task of the support from ensuring sufficient particle dispersion to participating in the catalytic cycle. Particularly interesting in this respect are so-called strong metal-support interactions (SMSI) which have been the subject of a number of catalytic studies since their discovery in the 1970s.[6] Many different transition-metal oxides, such as TiO 2 , [7] CeO 2 , [8] and WO 3 [9] are known to show a SMSI effect which can strongly influence the electronic structure of metal catalysts and even lead to thin oxide layers covering the metal nanoparticles.[10] While in some cases (e.g. toluene hydrogenation on Pt/TiO 2 [11] ) the SMSI effect was found to decrease the overall catalytic activity (by diminishing the number of active sites through encapsulation of the metal particles by the oxide), in other cases it can considerably improve activity (e.g. CO oxidation on Pt/TiO 2 [12] ). Such synergism can for instance result from the fact that the oxide provides special adsorption sites at the perimeter of the particles, [11] induces a different particle morphology, [7] or delivers active species.[12] Since CO oxidation on Pt, for instance, suffers from the fact that CO is strongly bound to Pt and thus poisons the surface so that O 2 cannot adsorb at low temperatures, a supply of oxygen by the support should improve the performance drastically. Indeed, this type of SMSI effect was recently observed: [13] The interaction of Pt with FeO, which delivers oxygen at the border between the two constituents, was exploited in the development of a very efficient catalyst for PROX (preferential oxidation of CO in the presence of hydrogen) which already works at room temperature. Besides the possible contribution of subsurface Fe, [14] the active site was discussed to be a highly reduced FeO layer on Pt, while hydrogen is necessary to replenish these reduced sites. [13] Although the potential of SMSI is clear and industrial companies are already benefitting from such catalysts, rational concepts to generate and tune SMSI are still largely missing in the literature. One possible strategy is the use of supported preformed colloidal nanoparticles instead of metal precursors which are assembled into particles only in subsequent steps on the surface. Here, spacers between the catalytic particle and the support in the form of organic ligands can be employed which can possibly mediate the interaction between the metal and the sup...

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Ligand Capping of Colloidally Synthesized Nanoparticles—A Way to Tune Metal–Support Interactions in Heterogeneous Gas‐Phase Catalysis

et al. 2011

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“…Among existing approaches catalytic hydrodechlorination is one of the most promising methods for this task [1]. Initially, the majority of studies in this field have focused on hydrodechlorination using noble metals as active phase and reagents supplied in gaseous phase [5,6]. However, research transitioned relatively quickly to low-cost alternatives, which resulted in the utilization of variety of transition metals (e.g., nickel, copper) for this purpose [7][8][9][10].…”

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confidence: 99%

Effect of metal precursor and pretreatment conditions on the catalytic activity of Ni/C in the aqueous phase hydrodechlorination of 1,1,2-trichloroethene

Kowalewski

Kamińska

Słowik

et al. 2017

Reac Kinet Mech Cat

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Active carbon supported nickel catalysts prepared with nickel(II) nitrate and nickel(II) chloride precursors after reduction at 673 or 1173 K were investigated in the aqueous phase hydrodechlorination of 1,1,2-trichloroethene (TCE). These nickel catalysts facilitate the purification of water via decomposing TCE, but their catalytic properties depend on the chemistry of the nickel precursor used for Ni/C synthesis and pretreatment conditions. The chemistry of precursor catalysts affects the particle size, which in turn is correlated with catalytic activity. We observed the highest activity for Ni/C with the largest nickel particles. The application of high temperature reduction of nickel precursors increases the activity and minimizes the differences between the catalytic properties of the samples prepared from different salts.

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“…20,21 Numerous experimental studies of Pt/CeO 2 systems used IR spectroscopy of adsorbed CO for clarification of the state of platinum species (Table 1) and their catalytic performance. 4,[22][23][24][25][26][27][28][29][30] For instance, Happel et al 22 have detected in IR spectra several vibrational bands when CO was adsorbed on ceria supported platinum nanoparticles ( Table 1). The bands at 1875 and 2080 cm -1 were attributed to CO in the bridge and top .…”

Section: Introductionmentioning

confidence: 99%

Can the state of platinum species be unambiguously determined by the stretching frequency of an adsorbed CO probe molecule?

Aleksandrov

Neyman

Hadjiivanov

et al. 2016

Phys. Chem. Chem. Phys.

140

128

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Electronic Supplementary Information (ESI) available: Information includes sketches of all modeled Pt8(CO) complexes in gas phase and some of their energetic and structural characteristics, structure of e-reg/(CO)2 complex, and figure with the changes of the CO stretching frequency versus oxidation state and Bader charge of mononuclear platinum species. See DOI: 10.1039/x0xx00000x The paper addresses possible ambiguities in determination of the state of platinum species by the stretching frequency of a CO probe, which is a common technique for characterization of platinum-containing catalytic systems. We present a comprehensive comparison of the available experimental data with our theoretical modeling (density functional) results of pertinent systems -platinum surface, nanoparticles and clusters as well as reduced or oxidized platinum moieties on ceria support. Our results for CO adsorbed on-top on metallic Pt . This trend corroborates the Kappers-van der Maas correlation derived from analysis of experimental stretching frequency of CO adsorbed on platinum-containing samples on different supports. We also analyzed the effect of the charge of platinum species on the CO frequency. Based on the calculated vibrational frequencies of CO in various model systems, we concluded that the actual state of the platinum species may be mistaken based only on the measured value of the C-O vibrational frequency due to overlapping regions of frequencies corresponding to different types of species. In order to identify the actual state of platinum species one has to combine this powerful technique with other approaches.

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Study of Pt–CeO2 interaction and the effect in the selective hydrodechlorination of trichloroethylene

Cited by 54 publications

References 32 publications

Ligand Capping of Colloidally Synthesized Nanoparticles—A Way to Tune Metal–Support Interactions in Heterogeneous Gas‐Phase Catalysis

Ligand Capping of Colloidally Synthesized Nanoparticles—A Way to Tune Metal–Support Interactions in Heterogeneous Gas‐Phase Catalysis

Effect of metal precursor and pretreatment conditions on the catalytic activity of Ni/C in the aqueous phase hydrodechlorination of 1,1,2-trichloroethene

Can the state of platinum species be unambiguously determined by the stretching frequency of an adsorbed CO probe molecule?

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