Insight into the surface composition of bimetallic nanocatalysts obtained from microemulsions

The enhancement of catalysts efficiency of bimetallic nanoparticles depends on the ability to exert control over surface composition. However, results relating surface composition and feeding solution of bimetallic nanoparticles synthesized in microemulsions are controversial and apparently contradictory. In order to comprehend how the resulting surface can be modified under different synthesis conditions and for different pairs of metals, a computer simulation study was carried out. The resulting surface compositions are explained based on the relative rates of deposition of the two metals, which depend on the particular metal pair, the concentration of reactants and the microemulsion composition. This study provides a satisfactory understanding of experimental results and allows us to identify the main factors affecting the nanoparticle's surface composition. Consequently, concrete and practical guidelines can be established to facilitate the experimental synthesis of bimetallic nanoparticles with tailored surfaces.