Combustor Study of the Deactivation of a Three-Way Catalyst by Lead and Manganese

The activity and durability of a platinum-rhodium automotive three-way catalyst were investigated as a function of lead and manganese fuel levels using a pulse-flame combustor. Total hydrocarbons, carbon monoxide, and nitric oxide conversions and three-way (HC/CO/NO) conversion efficiency windows were determined for approximately 24,000 combustor-simulated miles. The window for 80% HC/CO/NO efficiency disappeared at approximately 9,000 miles, 13,500 miles, and 4,500 miles for 0.5 g of lead per gallon of fuel, 0.0625 g of manganese per gallon of fuel, and a combined manganese and lead misfueling study, respectively. The catalyst's nitric oxide reduction activity displayed the greatest sensitivity to catalytic poisoning with both lead and manganese fuels.