The catalytic behavior of precisely synthesized Pt-Pd bimetallic catalysts for use as diesel oxidation catalysts

摘要

The demands of stricter diesel engine emission regulations have created challenges for current exhaust systems. With advances in low-temperature internal combustion engines and their operations, advances must also be made in vehicle exhaust catalysts. Most current diesel oxidation catalysts use heavy amounts of precious group metals (PGMs) for hydrocarbon (HC), CO, and NO oxidation. These catalysts are expensive and are most often synthesized with poor bimetallic interaction and dispersion. The goal of this work was to study the effect of aging on diesel emission abatement of Pt-Pd bimetallic nanoparticles precisely prepared with different morphologies: well dispersed core-shell vs. well dispersed homogeneously alloyed vs. poorly dispersed, poorly alloyed particles. Alumina and silica supports were studied. Particle morphology and dispersion were analyzed before and after hydrothermal treatments by XRD, EDX, and STEM. Reactivity as a function of aging was measured in simulated diesel engine exhaust.