ChemInform Abstract: Thermal Decomposition and Reformation of PdO Catalysts; Support Effects.

Farrauto, Robert J.; Lampert, Jordan; Hobson, M.C.; Waterman, Earl M.

doi:10.1002/chin.199547030

Cited by 1 publication

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, the formation of bulklike PdO is known to be responsible for the favorable performance of supported Pd catalysts in fuel-lean applications of methane oxidation. [1][2][3][4][5][6][7][8][9][10][11][12] The high activity of PdO as a complete oxidation catalyst certainly motivates detailed investigations of the chemistry of PdO surfaces. More generally, clarifying the chemical properties of late TM oxides is important for understanding the catalytic behavior of transition metals in oxidizing environments, which includes applications of catalytic combustion, fuel cell catalysis, and pollution control systems.…”

Section: Introductionmentioning

confidence: 99%

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H₂ on a PdO(101) Thin Film

et al. 2010

View full text Add to dashboard Cite

We investigated the dissociative chemisorption and oxidation of H 2 and D 2 on a PdO(101) thin film using temperature-programmed desorption (TPD) experiments and density functional theory (DFT) calculations. We find that the dissociation of H 2 is highly facile on PdO(101), with more than 90% of a saturated H 2 layer dissociating below 100 K. Most of the dissociated hydrogen reacts with the surface to produce H 2 O that desorbs above 350 K during TPD. Our experimental data demonstrate that H 2 dissociation on PdO(101) occurs by a precursor-mediated mechanism in which a molecularly chemisorbed H 2 species acts as a necessary precursor to dissociation. The experimental data also reveal that a kinetic isotope effect strongly suppresses the dissociation of D 2 on PdO(101) terraces and causes the kinetic branching to shift toward desorption of the molecular D 2 precursor. DFT calculations predict that H 2 binds relatively strongly on PdO(101) by forming a σ complex on a coordinatively unsaturated (cus) Pd site. Using DFT, we identified only a single pathway for H 2 dissociation that generates stable products on PdO(101). In this pathway, the adsorbed H 2 σ complex dissociates by transferring an H atom to a neighboring cus-O site, thereby producing an OH species and an H atom bound to a cus-Pd site. Zero-point-corrected barriers determined for this pathway fail to explain our experimental observations of facile dissociation of H 2 on PdO(101) and a strong kinetic isotope effect that suppresses D 2 dissociation. We present evidence that quantum mechanical tunneling dominates the dissociation of H 2 on PdO(101) at low temperatures and that differences in tunneling rates are responsible for the large kinetic isotope effect that we observe experimentally.

show abstract

Section: Introductionmentioning

confidence: 99%

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H₂ on a PdO(101) Thin Film

et al. 2010

View full text Add to dashboard Cite

show abstract

ChemInform Abstract: Thermal Decomposition and Reformation of PdO Catalysts; Support Effects.

Cited by 1 publication

References 1 publication

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H₂ on a PdO(101) Thin Film

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H₂ on a PdO(101) Thin Film

Contact Info

Product

Resources

About

ChemInform Abstract: Thermal Decomposition and Reformation of PdO Catalysts; Support Effects.

Cited by 1 publication

References 1 publication

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H2 on a PdO(101) Thin Film

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H2 on a PdO(101) Thin Film

Contact Info

Product

Resources

About

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H₂ on a PdO(101) Thin Film

Strong Kinetic Isotope Effect in the Dissociative Chemisorption of H₂ on a PdO(101) Thin Film