Monolithic Pt/Ce0.8Zr0.2O2/cordierite catalysts for low temperature water gas shift reaction in the real reformate

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.