Catalysts for Methanol Vehicles

A Methanol catalyst test program has been conducted in two phases. The purpose of Phase I was to determine whether a base metal or lightly-loaded noble metal catalyst could reduce Methanol engine exhaust emissions with an efficiency comparable to conventional gasoline engine catalytic converters. The goal of Phase II was the reduction of aldehyde and unburned fuel emissions to very low levels by the use of noble metal catalysts with catalyst loadings higher than those in Phase I.

Catalysts tested in Phase I were evaluated as three-way converters as well as under simulated oxidation catalyst conditions. Phase II catalysts were tested as three-way converters only.

For Phase I, the most consistently efficient catalysts over the range of pollutants measured were platinum/rhodium configurations. None of the catalysts tested in Phase I were able to meet a NOx level of 1 gram per mile when operated in the oxidation mode. Testing of the heavily loaded noble metal configurations in Phase II demonstrated that the use of loadings beyond 60 grams per cubic foot of substrate did not increase catalyst efficiency for most of the pollutants. Heavily loaded platinum/rhodium configurations were much more efficient converting the range of pollutants measured than the heavily loaded silver or silver/rhodium catalysts.