Advances in silicon epitaxial technology : D. C. Gupta and P. Wang, Solid-St. Technol., October (1968), p. 48

Abstract

Monolithic catalysts were prepared by washcoating Ce0.8Zr0.2O2 slurries and then impregnating platinum or rhenium onto cordierite substrates, and characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), inductively coupled plasma (ICP), temperature-programmed-reduction (TPR) and temperature-programmed deposition of CO (CO-TPD) techniques. The effects of preparation parameters on the catalytic performance for water gas shift (WGS) reaction were investigated in details, including different Ce0.8Zr0.2O2 powder as washcoat, coat loadings, metal loadings, Pt/Re weight ratio and impregnation sequences. In addition, pyrophoricity (exposure to oxygen stream) and long-term stability were carried out over monolithic catalysts with the optimized composition. The results showed that Ce0.8Zr0.2O2 prepared by microemulsion methods was the preferred washcoat, and that 50 wt% Ce0.8Zr0.2O2 coat loading and 0.68 wt% Pt loading were required to reduce CO content to ca. 1%. The optimal catalytic performance was achieved over 0.11 wt% Re/0.34 wt% Pt/50 wt% Ce0.8Zr0.2O2–M/cordierite catalyst. Pyrophoricity tests indicated that no obvious activity loss was observed over 0.11 wt% Re/0.34 wt% Pt/50 wt% Ce0.8Zr0.2O2–M/cordierite catalyst after three exposures to oxygen; while 17% of the initial activity was lost over industrial B206 after one exposure. Monolithic 0.11 wt% Re/0.34 wt% Pt/50 wt% Ce0.8Zr0.2O2–M/cordierite catalyst exhibited good stability during 80 h on-stream test.