Strategic synergy: advances in the shape control of bimetallic nanoparticles with dilute alloyed surfaces

Bimetallic nanoparticles with dilute alloyed surfaces are promising materials for many applications, especially catalysis. However, the preparation of nanoparticles composed of catalytically advantageous metal pairs is complicated by challenges, such as lattice mismatch and dissimilar reduction potentials. This review presents recent advances in nano-particle shape and composition control, and these syntheses can be classified as 'two-step' or 'one-step.' Two-step techniques use a premade particle that is modified by the deposition of the secondary metal via galvanic exchange, direct reduction, or underpotential deposition. In contrast, one-step methods such as seed-mediated coreduction, sequential coreduction, and underpotential deposition involve the simultaneous deposition of both metals. A perspective on ongoing synthetic challenges is also provided, as well as promising directions for future work.