Goncalves, Renato V.
Dias, Carlos Sato B.
Vono, Lucas L. R.
Teixeira, Sergio R.
Rossi, Liane M.
Total Authors: 8
 Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, BR-05508000 Sao Paulo - Brazil
 UMR CNRS 8181, UCCS, F-59655 Villeneuve Dascq - France
 Univ Lille Nord France, F-59000 Lille - France
 Univ Fed Mato Grosso do Sul, Inst Fis, BR-79070900 Campo Grande, MS - Brazil
 LNLS, BR-13083970 Sao Paulo - Brazil
 Univ Caxias Sul, BR-95700000 Bento Goncalves, RS - Brazil
 Univ Fed Rio Grande do Sul, Inst Fis, BR-90046900 Porto Alegre, RS - Brazil
Total Affiliations: 7
ACS APPLIED MATERIALS & INTERFACES;
APR 22 2015.
Web of Science Citations:
Copper catalysts are very promising, affordable alternatives for noble metals in CO oxidation; however, the nature of the active species remains unclear and differs throughout previous reports. Here, we report the preparation of 8 nm copper nanoparticles (Cu NPs), with high metallic content, directly deposited onto the surface of silica nanopowders by magnetron sputtering deposition. The as-prepared Cu/SiO2 contains 85% Cu-0 and 15% Cu2+ and was enriched in the Cu phase by H-2 soft pretreatment (96% Cu-0 and 4% Cu2+) or further oxidized after treatment with O-2 (33% Cu-0 and 67% Cu2+). These catalysts were studied in the catalytic oxidation of CO under dry and humid conditions. Higher activity was observed for the sample previously reduced with H-2, suggesting that the presence of Cu-metal species enhances CO oxidation performance. Inversely, a poorer performance was observed for the sample previously oxidized with O-2. The presence of water vapor caused only a small increase in the temperature require for the reaction to reach 100% conversion. Under dry conditions, the Cu NP catalyst was able to maintain full conversion for up to 45 h at 350 degrees C, but it deactivated with time on stream in the presence of water vapor. (AU)