CO Oxidation on PdO(101) during Temperature-Programmed Reaction Spectroscopy: Role of Oxygen Vacancies

2014 ◽  
Vol 118 (49) ◽  
pp. 28647-28661 ◽  
Author(s):  
Feng Zhang ◽  
Li Pan ◽  
Tao Li ◽  
John T. Diulus ◽  
Aravind Asthagiri ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxygen Vacancies ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction Spectroscopy ◽  
Temperature Programmed Reaction

Kinetics and selectivity of methane oxidation on an IrO2(110) film

2021 ◽  
Author(s):  
Christopher J Lee ◽  
Saumye Vashishtha ◽  
Mohammed Shariff ◽  
Fangrong Zou ◽  
Junjie Shi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Methane Oxidation ◽  
High Stability ◽  
Product Formation ◽  
Product Selectivity ◽  
Alkane Dehydrogenation ◽  
Highly Active ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction Spectroscopy ◽  
Temperature Programmed Reaction

Abstract Undercoordinated, bridging O-atoms (Obr) are highly active as H-acceptors in alkane dehydrogenation on IrO2(110) surfaces but transform to HObr groups that are inactive toward hydrocarbons. The low C-H activity and high stability of the HObr groups cause the kinetics and product selectivity during CH4 oxidation on IrO2(110) to depend sensitively on the availability of Obr atoms prior to the onset of product desorption. From temperature programmed reaction spectroscopy (TPRS) and kinetic simulations, we identified two Obr-coverage regimes that distinguish the kinetics and product formation during CH4 oxidation on IrO2(110). Under excess Obr conditions, when the initial Obr coverage is greater than that needed to oxidize all the CH4 to CO2 and HObr groups, complete CH4 oxidation is dominant and produces CO2 in a single TPRS peak between 450 and 500 K. However, under Obr-limited conditions, nearly all the initial Obr atoms are deactivated by conversion to HObr or abstracted after only a fraction of the initially adsorbed CH4 oxidizes to CO2 and CO below 500 K. Thereafter, some of the excess CHx groups abstract H and desorb as CH4 above ~500 K while the remainder oxidize to CO2 and CO at a rate that is controlled by the rate at which Obr atoms are regenerated from HObr during the formation of CH4 and H2O products. We also show that chemisorbed O-atoms (“on-top O”) on IrO2(110) enhance CO2 production below 500 K by efficiently abstracting H from Obr atoms and thereby increasing the coverage of Obr atoms available to completely oxidize CHx groups at low temperature. Our results provide new insights for understanding factors which govern the kinetics and selectivity during CH4 oxidation on IrO2(110) surfaces.

Methanol oxidation on stoichiometric and oxygen-rich RuO2(110)

2017 ◽  
Vol 19 (29) ◽  
pp. 18975-18987 ◽  
Author(s):  
Rahul Rai ◽  
Jason F. Weaver
Keyword(s):  
Methanol Oxidation ◽  
Oxidation Of Methanol ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction Spectroscopy ◽  
Temperature Programmed Reaction

We used temperature-programmed reaction spectroscopy (TPRS) to investigate the adsorption and oxidation of methanol on stoichiometric and O-rich RuO2(110) surfaces.

Role of Oxygen Vacancies in Water Vapor Chemisorption and CO Oxidation on Titania

1995 ◽  
Vol 170 (1) ◽  
pp. 215-219 ◽  
Author(s):  
G. Sengupta ◽  
R.N. Chatterjee ◽  
G.C. Maity ◽  
B.J. Ansari ◽  
C.V.V. Satyanarayna
Keyword(s):  
Water Vapor ◽  
Co Oxidation ◽  
Oxygen Vacancies
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