2-Propanol Dehydration on TiO2(110): The Effect of Bridge-Bonded Oxygen Vacancy Blocking
On 100 K rutile TiO2(110) surfaces with 3.5 0.5 % surface bridge-bonded oxygen vacancies (BBOV’s), propene formation by dehydration of 2-propanol was monitored by temperature programmed desorption (TPD). The BBOV’s were either filled or unfilled when the 2-propanol was dosed. Propene desorption rates exhibit two local maxima, nominally at 350 (LT) and 570 K (HT). The former is not altered by filling BBOV’s while the latter is reduced by factors of 2.5 and 5 when the vacancies are pre-filled with water (H-OH) and alcohol (R-OH), respectively. The HT process is attributed to a reaction of 2-propoxy groups located on surface BBO’s. To account for much of the HT C3H6 yield when BBOV’s are filled before (CH3)2CHOH dosing, we propose a model whereby, during TPD, vacancies form and are filled with 2-propoxy. The factor of two difference between titrating BBOV’s with H2O and alcohols is attributed to stoichiometry; twice as many OH groups form on surface BBO rows when H2O is used so twice as many vacancies are created when OH recombines.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 927279
- Report Number(s):
- PNNL-SA-57162; 24793; 14591; KC0302010
- Journal Information:
- Surface Science, 602(2):511-516, Journal Name: Surface Science, 602(2):511-516 Journal Issue: 2 Vol. 602; ISSN SUSCAS; ISSN 0039-6028
- Country of Publication:
- United States
- Language:
- English
Similar Records
Vacancy Assisted Diffusion of Alkoxy Species on Rutile TiO2(110)
Adsorption, Desorption, and Displacement Kinetics of H2O and CO2 on TiO2(110)