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Interactions of NO and SO2 with iron deposited on silica

1985; Elsevier BV; Volume: 104; Issue: 1 Linguagem: Inglês

10.1016/0021-9797(85)90029-3

1095-7103

Ranjani Siriwardane, Jason M Cook,

Gas Sensing Nanomaterials and Sensors

The interactions of NO and SO2 with both clean and iron-deposited, single-crystal surfaces of SiO2 at temperatures of 298, 473, and 673°K were studied using X-ray photoelectron spectroscopy. Neither NO nor SO2 showed any reaction with clean SiO2 at the three temperatures studied. The iron that was deposited onto the SiO2 surface remained in the metallic state. Both NO and SO2 interacted with this iron-covered silica (Fe/SiO2). The total amount of adsorbed gas increased with increased iron coverage. Two forms of nitrogen, nitride and molecularly adsorbed NO, were observed when an Fe/SiO2 surface at 298°K was exposed to NO. When the reaction was carried out at 473°K, the amount of nitride increased, but molecularly adsorbed NO was no longer observed. AT 673°K, neither form of nitrogen was observed. An adsorbed oxygen peak appeared at all three temperatures. The presence of both the nitride and the oxygen peaks indicated that dissociation of NO occurred on the Fe/SiO2 surface. When the Fe/SiO2 system at 298°K was exposed to SO2, two forms of sulfur, sulfate and sulfide, were observed. At 473°K the amount of sulfide increased slightly while the amount of sulfate decreased slightly. Neither form of sulfur was observed at 673°K.