Recent Advances in Synthesis of Small-Sized Intermetallic Compounds and Their Applications in Selective Hydrogenation

The well-defined and tunable structure of the intermetallic compounds (IMCs) has been extensively explored in various important heterogeneous catalysis and energy conversions in recent years. Nevertheless, the formation of an ordered structure typically requires high-temperature treatment to overcome kinetic barriers for atomic migration, which inevitably results in serious agglomeration and sintering of the nanoparticles. Therefore, it is critical to develop synthetic principles and strategies to suppress the aggregation of the IMCs, especially for noble metal catalysts, which can greatly improve metal atom utilization. In this review, we concentrate specifically on summarizing the synthetic protocols of small-sized IMCs and their catalytic performance for the selective hydrogenation of various unsaturated function groups. First, several typical preparation methods for small-sized IMCs are introduced. Subsequently, the application of IMCs in the selective hydrogenation of unsaturated functional groups in small organic molecules is discussed in detail. Finally, we highlight challenges encountered in understanding the synthetic processes, applications, and mechanistic insights of small-sized intermetallic compounds.