Evidence for slow uptake of hydrogen by titania-supported metal samples: Consequences for estimating metallic surface areas

Jiang, Xinpeng; Hayden, Terry F.; Dumesic, James A.

doi:10.1016/0021-9517(83)90040-4

Cited by 87 publications

(7 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interactions at metal–support interfaces are a central factor in the design of catalytic materials. A typical example is the strong metal–support interaction (SMSI) observed in Pt catalysts supported on TiO 2 , which has been widely studied since the 1970s. − Tauster et al found that Pt/TiO 2 catalysts totally lose their chemisorption capacities for H 2 and CO after reduction treatment at high temperatures (≥400 °C), where Pt sintering is not obvious. In the SMSI state, a catalyst changes its catalytic activities and selectivities for reactions involving H 2 and CO.…”

Section: Introductionmentioning

confidence: 99%

Phase-Dependent Formation of Coherent Interface Structure between PtO₂ and TiO₂ and Its Impact on Thermal Decomposition Behavior

et al. 2017

View full text Add to dashboard Cite

This study investigated the thermal decomposition behaviors of platinum oxide (PtO2) nanoparticles deposited on polycrystalline TiO2 in different crystal phases. The dissociation of PtO2 to metallic platinum in air occurred at 400 °C on anatase TiO2 (Pt/TiO2-A), but required 650 °C or higher on rutile TiO2 (Pt/TiO2-R). The higher thermal stability of PtO2 on rutile TiO2 is caused by thermodynamic effect and rather than kinetic effect. In contrast to the thermodynamic prediction, metallic Pt (Pt0) on TiO2-R was reversibly oxidized to PtO2 (Pt4+) at 650 °C. This behavior was attributed to the coherent interface structure formed by strong interactions between PtO2 and rutile TiO2, as revealed by combined extended X-ray adsorption spectroscopy (EXAFS) and density functional theory (DFT) studies. At the optimized interface structure, between the (100) planes of α-PtO2 and rutile TiO2, the interface formation energy was −17.04 kJ mol–1 Å–2 versus −9.84 kJ mol–1 Å–2 in the anatase TiO2 model. The larger interface formation energy provides a stabilizing effect against PtO2 dissociation. Therefore, the widely used Pt-loaded rutile TiO2 typifies the interfacial interactions under an oxidizing atmosphere, which differ from the strong metal–support interactions prevailing under a reducing atmosphere.

show abstract

Section: Introductionmentioning

confidence: 99%

Phase-Dependent Formation of Coherent Interface Structure between PtO₂ and TiO₂ and Its Impact on Thermal Decomposition Behavior

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Metal particles can undergo substantial modifications in catalytic behavior when dispersed on different support materials. The impact of the establishment of chemical and physical interactions between metal particles and the support on the catalytic activity and selectivity for a given reaction has been the subject of numerous papers and excellent reviews have been written about this topic. − The most dramatic changes in the catalytic performance were found when titania or other readily reducible oxides were employed as support media. ,,− Indeed, the investigations of the so-called strong metal−support interaction (SMSI effect) reported by Tauster and co-workers 3,4 gave rise to an avalanche of papers and a debate that centered around the origin of the observed changes in catalytic activity. Several explanations were proposed to account for the decrease in hydrogen chemisorption capacity of various metal/TiO 2 systems, following reduction at temperatures of about 500 °C.…”

Section: Introductionmentioning

confidence: 99%

Induction of an Electronic Perturbation in Supported Metal Catalysts

and

Baker

2000

J. Phys. Chem. B

View full text Add to dashboard Cite

The debate as to whether an “electronic” effect is responsible for perturbations in the normal behavior of supported metal catalysts has seized the attention of scientists for many years. Unfortunately, many of the proposed so-called “electronic” models can now be more satisfactorily explained in terms of either the surface concentration or the size of the ensembles present on the support surface. In this study we have used both ferroelectric and selected ceramic support media to demonstrate that at specific temperatures the catalytic activity of a supported metal particle can be enhanced to a significant degree. The observed improvement in the performances of these systems can be correlated with changes in the structure of the support media and to the different dielectric constants exhibited by these materials. A further aspect that must be taken into consideration is the finding from high-resolution TEM examinations that even after mild reduction at 350 °C there was evidence that in the vicinity of metal particles the support underwent transformation to a lower oxide state.

show abstract

“…The fact that an exact parabolic law is not always found in the intermediate region of the plots of Figs lb or 2b might be explained assuming a more complex diffusion equation (e.g. with the linear term) or the interference of some chemisorption kinetics, diffusion into the bulk might be favoured by bulk Ti 3+ produced during the pretreatment [22]. Some more complex mechanisms, e.~ some chemisorption kinetics.…”

Section: Resultsmentioning

confidence: 93%

Calorimetric study of the kinetics of adsorption of hydrogen loaded titanium oxide

Stradella

1988

Journal of Thermal Analysis

View full text Add to dashboard Cite

The thermol~inetics of the adsorption of hydrogen on a loaded titanium dioxide has been studied by microcalorimetry.A diffusion process in the open structure of the oxide seems to be the rat6r determim'ng step. Some exceptions at the rule of the S-shaped z-t plot were found.The function "z" is here obtained from the thermokinetics of the process and is constituted by the reciprocal of the time derivative of the fraction of the integra~ heat of adsorption, i.e., by the reciprocal of the relative heat flow.A review of empirical isotherms and of theoretical models proposed for the kinetics of adsorption has been recently published [1]. One conclusion of this paper is that the plot of the reciprocal of the rate of adsorption against time is convex at small "t" and concave at large "t" and the region of constant rate sometimes proceeds the convex region.The present article which deals with the adsorption of hydrogen on a doped titanium dioxide attempts to show that some exceptions to this rule may occur. ExperimentalThe material studied was a titania-based catalyst that is proposed for the production of hydrogen by the photocleavage of water [2]. A sample of TiO2 from Degussa (P-25, surface area 55 mZ/g; 72% anatase, 28% rutile) was loadedJohn Wiley & Sons, Limited, Chichester Akad~niai Kiad6, Budapest

show abstract

Evidence for slow uptake of hydrogen by titania-supported metal samples: Consequences for estimating metallic surface areas

Cited by 87 publications

References 27 publications

Phase-Dependent Formation of Coherent Interface Structure between PtO₂ and TiO₂ and Its Impact on Thermal Decomposition Behavior

Phase-Dependent Formation of Coherent Interface Structure between PtO₂ and TiO₂ and Its Impact on Thermal Decomposition Behavior

Induction of an Electronic Perturbation in Supported Metal Catalysts

Calorimetric study of the kinetics of adsorption of hydrogen loaded titanium oxide

Contact Info

Product

Resources

About

Evidence for slow uptake of hydrogen by titania-supported metal samples: Consequences for estimating metallic surface areas

Cited by 87 publications

References 27 publications

Phase-Dependent Formation of Coherent Interface Structure between PtO2 and TiO2 and Its Impact on Thermal Decomposition Behavior

Phase-Dependent Formation of Coherent Interface Structure between PtO2 and TiO2 and Its Impact on Thermal Decomposition Behavior

Induction of an Electronic Perturbation in Supported Metal Catalysts

Calorimetric study of the kinetics of adsorption of hydrogen loaded titanium oxide

Contact Info

Product

Resources

About

Phase-Dependent Formation of Coherent Interface Structure between PtO₂ and TiO₂ and Its Impact on Thermal Decomposition Behavior

Phase-Dependent Formation of Coherent Interface Structure between PtO₂ and TiO₂ and Its Impact on Thermal Decomposition Behavior