Selective hydrogenation—adding “just enough” hydrogen—is critical for a wide range of industrial processes including the manufacturing of polymers and pharmaceuticals. A catalyst can facilitate the supply of hydrogen atoms to a reaction by splitting hydrogen molecules and facilitating migration along the catalyst surface. But what determines how good a catalyst is at dissociating hydrogen? Researchers from Harvard University and UCLA joined forces to address this question, and found something surprising on the way, as described in a recent ACS Catalysis article. By combining theory and experiments they assessed the kinetics and energetics of hydrogen dissociation of a nanoparticle catalyst of particular interest for selective hydrogenation, (dilute Pd-in-Au). Their surprising discovery is that the rate of dihydrogen dissociation depends on the Pd ensemble size—that is, how many Pd atoms are grouped together at the surface. This knowledge will be helpful in designing more efficient hydrogenation catalysts.
July 13, 2021