Tuning the Catalytic Activity of PdxNiy (x + y = 6) Bimetallic Clusters for Hydrogen Dissociative Chemisorption and Desorption

Density functional theory was used to study dissociative chemisorption and desorption on PdxNiy (x + y = 6) bimetallic clusters. The H2 dissociative chemisorption energies and the H desorption energies at full H saturation were computed. It was found that bimetallic clusters tend to have higher chemisorption energy than pure clusters, and the capacity of Pd3Ni3 and Pd2Ni4 clusters to adsorb H atoms is substantially higher than that of other clusters. The H desorption energies of Pd3Ni3 and Pd2Ni4 are also lower than that of the Pd6 cluster and comparable to that of the Ni6 cluster, indicating that it is easier to pull the H atom out of these bimetallic catalysts. This suggests that the catalytic efficiency for specific PdxNiy bimetallic clusters may be superior to bare Ni or Pd clusters and that it may be possible to tune bimetallic nanoparticles to obtain better catalytic performance.