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.