Water gas shift reaction for the reformed fuels over Cu/MnO catalysts prepared via spinel-type oxide

Cu/MnO catalysts prepared via reduction of Cu–Mn spinel oxide were investigated for development of active Cu catalysts for the water gas shift reaction (WGSR). A Cu–Mn catalyst active for the WGSR was obtained after high temperature calcination at 900 °C and subsequent reduction. The optimum Cu/Mn ratio for catalytic activity of the Cu–Mn oxide system was 1/2. Nonstoichiometric Cu1.5Mn1.5O4 phase existed stably when copper manganese oxide was calcined above 700 °C. The optimized Cu–Mn spinel showed excellent WGSR activity when a larger percentage of CO was used, as in hydrocarbon reforming. Cu–Mn spinel oxides calcined above 900 °C were easily reduced. This may be responsible for the high activity of the Cu/MnO catalyst. Carbon dioxide in the reformed gas significantly depressed WGSR activity below 200 °C, while CO conversion reached equilibrium at 200 °C in the absence of CO2.