Platinized tin oxide catalysts for CO2 lasers: Effects of pretreatment
Abstract
Platinized tin oxide surfaces used for low-temperature CO oxidation in CO2 lasers have been characterized before and after reduction in CO at 125 and 250 C using ion scattering spectroscopy (ISS) and X ray photoelectron spectroscopy (XPS). XPS indicates that the Pt is present initially as PtO2. Reduction at 125 C converts the PtO2 to Pt(OH)2 while reduction at 250 C converts the PtO2 to metallic Pt. ISS shows that the Pt in the outermost atomic layer of the catalyst is mostly covered by substrate species during the 250 C reduction. Both the ISS and XPS results are consistent with Pt/Sn alloy formation. The surface dehydration and migration of substrate species over surface Pt and Sn appear to explain why a CO pretreatment at 250 C produces inferior CO oxidation activities compared to a 125 C pretreatment.
- Publication:
-
Low-Temperature CO-Oxidation Catalysts for Long-Life CO2 Lasers
- Pub Date:
- June 1990
- Bibcode:
- 1990ltco.rept..217G
- Keywords:
-
- Carbon Dioxide Lasers;
- Carbon Monoxide Lasers;
- Catalysts;
- Catalytic Activity;
- Metal Films;
- Platinum;
- Pretreatment;
- Tin Oxides;
- Atoms;
- Dehydration;
- Ion Scattering;
- Low Temperature;
- Metal Surfaces;
- Migration;
- Oxidation;
- Oxidation-Reduction Reactions;
- Photoelectron Spectroscopy;
- Substrates;
- X Ray Spectroscopy;
- Lasers and Masers