Spatial distance effect of bimetallic active sites for selective hydrogenation

The primary challenge in hydrogenation reactions is the trade-off between selectivity and activity. Many factors including the nanoparticle geometry, chemical composition, metal-support interaction, and electronic interaction can significantly influence the catalytic properties of metal active sites. A novel strategy involving bimetallic active sites with different distances (spatially intimate and spatially isolated) has shown remarkable enhancements in both activity and selectivity for a wide range of selective hydrogenation. Advances in synthesis methodologies and characterization tools allow correlation at molecular/atom levels. In this review, the electronic and geometric structures will be discussed on bimetallic active sites with tightly intimated and spatially separated structures. Meanwhile, we will discuss in detail the construction methods, synergistic effects, and hydrogenation mechanisms of bimetallic active sites. Finally, this perspective illustrates the developments and challenges associated with bimetallic active sites in hydrogenation and provides valuable insights through successful cases to guide the design of highly efficient hydrogenation catalysts.