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Kinetics and mechanisms of the oxidation of sulfur dioxide over titanium dioxide and nickel oxide

1977; Wiley; Volume: 9; Issue: 3 Linguagem: Inglês

10.1002/kin.550090316

1097-4601

Jae Shi Choi, Keu Hong Kim, Sung Rack Choi,

Industrial Gas Emission Control

Abstract The reactions between SO 2 and O 2 were carried out in the presence of TiO 2 and NiO under various partial pressures of SO 2 and O 2 at temperatures from 240 to 330°C. TiO 2 and NiO were pretreated by applying an annealing effect from which the catalysts would have the different activity. The rates are the highest for TiO 2 pretreated at high temperature in the region of 400 to 600deg;C in vacuum, 1.21 × 10 −4 mmHg. In contrast, the rates are the lowest for NiO pretreated at high temperaturefrom 350 to 550°C. The data have been correlated with 1.4 and first‐order kinetics for TiO 2 and NiO, respectively. A reaction mechanism to explain the data was suggested. The quantities of anionic vacancies in TiO 2 surfaces and of positive holes in NiO appeared to be paramount in determining the type of kinetics.