Catalytic Oxidation of Unburned Methanol with Presence of Engine Exhaust Components from a Methanol-Fueled Engine

Abstract

The mathanol oxidation reaction on the catalysts of Pt, Pd, Rh, Ir and Cu has been investigated to select the suitable catalysts for the purification of methanol engine exhaust gases. On all of these catalysts, the presence of NO showed an inhibitory effect on the methanol oxidation reaction and caused the formation of formaldehyde. By comparison with other exhaust components (CO, H₂O, HC), it was found that NO had a stronger effect than other species. Under the presence of NO, the relative activity sequence was also obtained as Pt≒Pd>Rh≒Ir>Cu. The temperature conditions for formaldehyde formation were revealed for each catalyst in the presence of NO, and it was also found that formaldehyde formation was most suppressed by use of the Pd catalyst. Consequently, Pd is one of the advantageous catalysts for reducing unburned methanol.