scholarly journals Step dynamics and oxide formation during CO oxidation over a vicinal Pd surface

2016 ◽  
Vol 18 (30) ◽  
pp. 20312-20320 ◽  
Author(s):  
Mikhail Shipilin ◽  
Johan Gustafson ◽  
Chu Zhang ◽  
Lindsay Richard Merte ◽  
Edvin Lundgren

Under CO oxidation reaction conditions the surface of Pd(553) adopts different structures depending on O2 partial pressure.

2019 ◽  
Vol 150 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Y. Suchorski ◽  
I. Bespalov ◽  
J. Zeininger ◽  
M. Raab ◽  
M. Datler ◽  
...  

Abstract The catalytic CO oxidation reaction on stepped Rh surfaces in the 10−6 mbar pressure range was studied in situ on individual μm-sized high-Miller-index domains of a polycrystalline Rh foil and on nm-sized facets of a Rh tip, employing photoemission electron microscopy (PEEM) and field-ion/field-emission microscopy (FIM/FEM), respectively. Such approach permits a direct comparison of the reaction kinetics for crystallographically different regions under identical reaction conditions. The catalytic activity of the different Rh surfaces, particularly their tolerance towards poisoning by CO, was found to be strongly dependent on the density of steps and defects, as well as on the size (µm vs. nm) of the respective catalytically active surface. Graphic Abstract


2021 ◽  
Author(s):  
Jan Knudsen ◽  
Tamires Gallo ◽  
Virgínia Boix ◽  
Marie Strømsheim ◽  
Giulio D'Acunto ◽  
...  

Abstract Heterogeneous catalyst surfaces are highly dynamic entities that respond rapidly to changes in their local gas environment, and the dynamics of the response is a decisive factor for the catalysts’ action and activity. Few probes are able to map catalyst structure and local gas environment simultaneously under reaction conditions at the time scales of the dynamic changes. Here we use the CO oxidation reaction over a Pd(100) surface exposed to pressures of 3 and 100 mbar of a CO + O2 gas mixture to demonstrate how such studies can be performed by time-resolved ambient pressure photoelectron spectroscopy. Central elements of the method are cyclic gas pulsing and software-based event-averaging by image recognition of spectral features. For the CO oxidation reaction over Pd(100) our main finding is that that all surface phases – the CO-covered Pd surface, a surface oxide and a thick PdOx phase – catalyse the CO oxidation reaction, in dependence on the supply of gas phase reactants.


1999 ◽  
Vol 103 (30) ◽  
pp. 6267-6271 ◽  
Author(s):  
A. Böttcher ◽  
M. Rogozia ◽  
H. Niehus ◽  
H. Over ◽  
G. Ertl

2015 ◽  
Vol 93 (7) ◽  
pp. 696-701 ◽  
Author(s):  
Hui Li ◽  
Yuanbin She ◽  
Haiyan Fu ◽  
Meijuan Cao ◽  
Jing Wang ◽  
...  

The synergistic effect of cyclohexane and cyclohexanone promoted synthesis of adipic acid catalyzed by [MnIIIT(p-Cl)PP]Cl with cyclohexane and cyclohexanone as co-reactants. The results showed that the conversions of cyclohexane and cyclohexanone were significantly enhanced because of the cyclohexanone synergistic effect, and the higher selectivity to adipic acid was obtained with dioxygen as an oxidant. The studies indicated that the co-oxidation of cyclohexane and cyclohexanone was influenced by the initial molar ratio of cyclohexanone and cyclohexane, catalyst structure, catalyst concentrations, and reaction conditions. The preliminary mechanism of the co-oxidation reaction of cyclohexane and cyclohexanone using [MnIIIT(p-Cl)PP]Cl as the catalyst was proposed.


2011 ◽  
Vol 13 (7) ◽  
pp. 2571 ◽  
Author(s):  
J. Chris Bauer ◽  
David Mullins ◽  
Meijun Li ◽  
Zili Wu ◽  
E. Andrew Payzant ◽  
...  

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