Tetraoxygen on reduced TiO2(110): oxygen adsorption and reactions with bridging oxygen vacancies.
Oxygen adsorption on reduced TiO2(110) is investigated using temperature programmed desorption and electron-stimulated desorption. At low temperatures, 2 O(2) molecules can be chemisorbed in each oxygen vacancy. These molecules do not desorb upon annealing to 700 K. Instead, for 200 K<T<400 K, the 2 O(2) convert to another species, which has four oxygen atoms, i.e., tetraoxygen, that decomposes at higher temperatures. In contrast, when only 1 O(2) is adsorbed in an oxygen vacancy, the molecule dissociates upon annealing above ~150 K to heal the vacancy in agreement with previous results.
Kimmel
Greg A
GA
Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA. gregory.kimmel@pnl.gov
Petrik
Nikolay G
NG