The N(2)O decomposition kinetics and the product (N(2) and CO(2)) desorption dynamics were studied in the course of a catalyzed N(2)O+CO reaction on Pd(110) by angle-resolved mass spectroscopy combined with cross-correlation time-of-flight techniques. The reaction proceeded steadily above 400 K, and the kinetics was switched at a critical CO/N(2)O pressure ratio. The ratio was about 0.03 at 450 K and reached approximately 0.08 at higher temperatures. Below it, the reaction was first order in CO, and negative orders above it. Throughout the surveyed conditions, the N(2) desorption sharply collimated along about 45 degrees off the normal toward the [001] direction. Desorbing N(2) showed translational temperatures in the range of 2000-5000 K. It is proposed that the decomposition proceeds in N(2)O(a) oriented along the [001] direction. On the other hand, the CO(2) desorption sharply collimated along the surface normal, showing a translational temperature of about 1600 K.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/la0507030 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Hydride-Induced Reconstruction of Pd Electrode Surfaces: A Combined Computational and Experimental Study.
Adv Mater
December 2024
Physics of Energy Conversion and Storage, Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748, Garching, Germany.
Designing electrocatalysts with optimal activity and selectivity relies on a thorough understanding of the surface structure under reaction conditions. In this study, experimental and computational approaches are combined to elucidate reconstruction processes on low-index Pd surfaces during H-insertion following proton electroreduction. While electrochemical scanning tunneling microscopy clearly reveals pronounced surface roughening and morphological changes on Pd(111), Pd(110), and Pd(100) surfaces during cyclic voltammetry, a complementary analysis using inductively coupled plasma mass spectrometry excludes Pd dissolution as the primary cause of the observed restructuring.
View Article and Find Full Text PDFTime-resolved surface reaction kinetics in the pressure gap.
Faraday Discuss
August 2024
Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm 100 44, Sweden.
We extend the use of our recently developed Near-Ambient Pressure Velocity Map Imaging (NAP-VMI) technique to study the kinetics and dynamics of catalytic reactions in the pressure gap. As an example, we show that NAP-VMI combined with molecular beam surface scattering allows the direct measurement of time- and velocity-resolved kinetics of the scattering and oxidation of CO on the Pd(110) surface with oxygen pressures at the surface up to 1 × 10 mbar, where different metastable surface structures form. Our results show that the c(2 × 4) oxide structure formed at low O pressure is highly active for CO oxidation.
View Article and Find Full Text PDFHighly Rotationally Excited N Reveals Transition-State Character in the Thermal Decomposition of NO on Pd(110).
J Am Chem Soc
June 2023
Department of Dynamics at Surfaces, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, Göttingen 37077, Germany.
We employ time-slice and velocity map ion imaging methods to explore the quantum-state resolved dynamics in thermal NO decomposition on Pd(110). We observe two reaction channels: a thermal channel that is ascribed to N products initially trapped at surface defects and a hyperthermal channel involving a direct release of N to the gas phase from NO adsorbed on bridge sites oriented along the [001] azimuth. The hyperthermal N is highly rotationally excited up to = 52 (″ = 0) with a large average translational energy of 0.
View Article and Find Full Text PDFApplication of machine-learning-based global optimization: potential-dependent co-electrosorbed structure and activity on the Pd(110) surface.
Phys Chem Chem Phys
August 2022
School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, 201418, China.
Electrodes can adsorb different reaction intermediates under electrochemical conditions, which in turn significantly affect their electrochemical performance. This complex phenomenon attracts continuous interest in both science and industry for understanding the co-electrosorbed structure and activity under electrochemical conditions. Here, we report the first theoretical attempt by combining the machine-learning-based global optimization (SSW-NN method) and modified Poisson-Boltzmann continuum solvation (CM-MPB) based on first-principles calculations to elucidate the potential-dependent co-electrosorbed species on the Pd(110) surface.
View Article and Find Full Text PDFNear-ambient pressure velocity map imaging.
J Chem Phys
July 2022
Department of Chemical Engineering, KTH Royal Institute of Technology, Stockholm 100 44, Sweden.
Article Synopsis
- A new instrument called NAP-VMI allows researchers to study how molecules scatter off surfaces at near-ambient pressures, bridging the gap between surface science and catalysis.
- The device uses ion optics to create a controlled environment that maintains vacuum while manipulating high-pressure ionization.
- Initial tests show promising results with various chemical reactions, suggesting NAP-VMI could be beneficial for diverse experiments like photoelectron spectroscopy and interactions involving liquids.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!