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Facet dependent pairwise addition of hydrogen over Pd nanocrystal catalysts revealed via NMR using PHIP

Release time:2017-4-6      Source:admin      Reads:786




     We demonstrated the facet dependence of pairwise addition of hydrogen in heterogeneous catalysis over Pd nanocryatal catalysts via NMR using para-hydrogen-induced polarization. This is the first time the observation of facet dependence of the pairwise addition of hydrogen on nanoparticle catalysts in the heterogeneous catalysis. The well-defined Pd nanocrystals show different fractions of Pd(100) to Pd(111) plane atoms on the surface, enabling to reveal the relationship between the Pd facets and the pairwise hydrogen addition in the hydrogenation catalysis. While the semi-hydrogenation of MBY to MBE are almost equally active on Pd(111) and/or Pd(100) surface, our results show that the pairwise hydrogen addition is favored on the Pd(111) facets. The binding of PVP stabilizer to the Pd nanoparticle surface is proposed to account for the observed PHIP effect on different Pd facets. These results not only shed new insight into the hydrogenation mechanism of alkynol over heterogeneous catalysts but also can help the design of hydrogenation catalyst to efficiently produce PHIP for more potential chemistry and biomedicine applications.