Heterogeneous uptake of carbonyl sulfide on hematite and hematite-NaCl mixtures.
Heterogeneous uptake of carbonyl sulfide (COS) on hematite, NaCl, and a series of hematite-NaCl mixtures was investigated in a static reaction chamber at 298 K using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The adsorbed COS was oxidized on the surface of hematite and hematite-NaClmixtures, forming surface hydrogen thiocarbonate (HSCO2-), carbonate (CO3(2-)), and sulfate (SO4(2-)) species as well as gaseous CO2. The reactivity of hematite-NaCI mixtures was lower than that of hematite alone. No uptake of COS was observed on the pure NaCl sample. For mixtures, the 40% hematite + 60% NaCl sample exhibited the highest reactivity. Preadsorption experiments using CO2 as a probe molecule indicated that about 70% of adsorbed COS was oxidized by surface oxygen ions on hematite. In contrast, the Fe-CIO species formed during the sample preparation procedure is proposed to be the active site on the hematite-NaCI mixtures. A plausible reaction mechanism of the heterogeneous oxidation of COS is proposed, and atmospheric implications based on these results are discussed.
Chen
Haihan
H
Center of Atmospheric Chemistry Studies, Department of Environmental Science & Engineering, Fudan University, 220 Handan Road, Shanghai 200433, People's Republic of China.
Kong
Lingdong
L
Chen
Jianmin
J
Zhang
Renyi
R
Wang
Lin
L
D000327:Adsorption; D005290:Ferric Compounds / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D010084:Oxidation-Reduction; D012965:Sodium Chloride / Q000737:chemistry*; D013461:Sulfur Oxides / Q000737:chemistry*
D005290:Ferric Compounds; D013461:Sulfur Oxides; C000499:ferric oxide; D012965:Sodium Chloride; C010063:carbonyl sulfide