Theoretical research on the H2 generation mechanism on Pt6, Pt5Sn5 and Pt3Sn6 clusters by density functional theory

In this paper, the mechanisms of H2 evolution on Pt6, Pt5Sn5, and Pt3Sn6 clusters were respectively investigated by the B3LYP method of density functional theory (DFT). The B3LYP functional with non-local dispersion corrections (B3LYP-D3) method were performed to investigate the adsorption of H and H+ on clusters. The calculation results indicated that the adsorption energy of H on Pt reduced due to the interaction of Sn and Pt, which promoted H desorption from Pt to form H2. Meanwhile, Sn atom of Pt5Sn5 and Pt3Sn6 clusters had strong interaction with H+ due to the existence of Pt, which was benefit for the reduction of H+ on Sn atom. As a consequence, Pt5Sn5 and Pt3Sn6 showed lower potential barrier and higher activities than Pt for H2 evolution. The potential barriers of H2 formation over Pt3Sn6 clusters was only 11.1% of that over Pt cluster.