Schanke, D.; Hilmen, A. M.; Bergene, E.; Kinnari, K.; Rytter, E.; Adnanes, E.; Holmen, A.

Catalysis Letters (1995), 34(3,4), 269-84 CODEN: CALEER; ISSN: 1011-372X. English.

The influence of water on alumina-supported cobalt catalysts has been studied. The deactivation of supported Co catalysts was studied in a fixed-bed reactor using synthesis gas feeds containing different concns. of water vapor. Supporting model studies were carried out using H2O/H2 feeds in conjunction with XPS and gravimetry. Rapid deactivation occurs on Re-promoted Co/Al2O3 catalysts when H2/CO/H2O feeds are used, but unpromoted Co/Al2O3 shows more stable activity. The results from the gravimetric studies suggest that only a small fraction of the bulk cobalt metal initially present reoxidizes to cobalt oxide during reaction. However, the XPS results indicate significant reoxidn. of surface cobalt atoms or highly dispersed cobalt phases, which is likely to be the cause of the observed deactivation. Rhenium is shown to have a marked effect on the extent of reoxidn. of alumina-supported cobalt catalysts.