Enhancing the catalytic and electrocatalytic properties of Pt-based catalysts by forming bimetallic nanocrystals with Pd

Bimetallic nanocrystals consisting of two distinct metals such as Pd and Pt are attractive for a wide variety of catalytic and electrocatalytic applications as they can exhibit not only a combination of the properties associated with both metals but also enhancement or synergy due to a strong coupling between the two metals. With Pd as the base metal, many methods have recently been demonstrated for the synthesis of Pd-Pt bimetallic nanocrystals having a wide variety of different structures in the form of alloys, dendrites, core-shells, multi-shells, and monolayers. In this tutorial review, we begin with a brief discussion on the possible structures of Pd-Pt bimetallic nanocrystals, followed by an account of recent progress on synthetic approaches to such nanocrystals with controlled structures, shapes and sizes. In addition to the experimental procedures and mechanistic studies, a number of examples are presented to highlight the use of such bimetallic nanocrystals as catalysts or electrocatalysts for various applications with enhanced performance relative to their monometallic counterparts.