Effects of a platinum-cerium bimetallic fuel additive on the chemical composition of diesel engine exhaust particles

The use of a platinum-cerium bimetallic fuel additive has been proposed as a cost-effective strategy for reducing particulatematter (PM) andNOx emissions fromdiesel-powered engines.Although previous studies have demonstrated that the use of platinum-cerium bimetallic fuel additive reduced emissions from diesel engines, there have been no reported investigations of howthe use of these fuel-borne catalysts (FBCs) impact the chemical and physical properties of diesel PMemissions. The present study demonstrates that the use of a platinum-cerium bimetallic fuel additive has a significant impact on the detailed chemical composition and size distribution of PM emitted from a diesel engine. Tests were conducted to explore the impact of different fuel concentrations of the fuel-borne catalyst at different engine-operating conditions. These tests were performed with a medium-duty diesel engine that was not equipped with exhaust gas recirculation or a diesel particulate filter (DPF). The results demonstrated that the use of the additive significantly reduced the emissions of PM2.5 and carbonaceous species. The reduction was 34% for thePM2.5mass, 54% for thePM2.5 elemental carbon, and 23%for thePM2.5 organic carbonwhen 0.1 ppmPt and 7.5ppmCe of the additivewere used. Emissions of particle-phase metals originating from the additive had a significant contribution to particle matter emissions when 0.7 ppm Pt and 42 ppm Ce of the additive were used. The particle size distribution of platinum in the PMemissions was different from the size distribution of cerium. The cerium/ platinum ratio in thePM2.5 diesel particle emissions ranged from 119 to 656, which was much higher than the ratio in the fuel additive that was 58.5 ( 5.6, indicating a higher penetration of cerium through the engine. copyright