Fine-tuning Au@Pd nanocrystals for maximum plasmon-enhanced catalysis

Core–shell nanocrystals with plasmonic metals as cores and catalytic metals as shells, have recently received considerable attention due to their enhanced catalytic properties under visible light irradiation. However, it remains illusive how sizes/shapes of cores and shells influence catalytic efficiency. Here, using Au@Pd nanocrystals as a model system, key parameters including Au core size/shape and Pd shell thickness are scrutinized to systematically examine how they influence reaction rate. The comparison is based on normalizing Pd amount, which is important from economics standpoint. The results show that the reaction rate decreases with the increase in shell thickness. With the fixed shell thickness, the maximum reaction rate occurs in the smallest core. Among four different core shapes (nanocube, nanorod, nanohexagon, and nanostar), Au@Pd nanorods display the highest reaction rate and the highest plasmonic enhancement factor. These findings may provide a rational route to screen desired plasmonic nanocatalyst with a balanced consideration of efficiency and economics.