Methane Steam Reforming on the Pt/CeO2 Catalyst: Effect of Daily Start-Up and Shut-Down on Long-Term Stability of the Catalyst

An environmentally friendly auxiliary power unit requires catalysts operating in the cyclic mode, producing H-2 at a steady rate with high CO2 selectivity and minimum CO clean-up. Here, 1% Pt/CeO2 catalyst was synthesized using the solution combustion synthesis method and investigated toward methane steam reforming reaction. Preliminary tests were performed by varying the steam-to-carbon ratio (S/C), gas hourly space velocity (GHSV), and time-on-stream (TOS). The catalyst showed near equilibrium CH4 conversion and high H-2 concentration (75% dry basis, N-2-free) obtained at S/C = 2.8 and GHSV = 24 000 h(-1). The catalytic activity was stable after 25 cycles of start-up and shut-down operations, equivalent to 150 h of TOS. X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques were used to characterize either the fresh and aged catalyst after 150 h of TOS.