Diffusion of a Single Platinum Atom on Light-Element-Doped Graphene

5 years ago

Diffusion of a Single Platinum Atom on Light-Element-Doped Graphene

Norihito Sakaguchi, Shun Hasegawa, Yuji Kunisada

Light-element-doped graphene is a promising support for polymer electrode fuel cell electrode catalysts. To understand the behavior of catalyst atoms on light-element-doped graphene, we investigated the adsorption states and diffusion behavior of a single Pt atom on pristine graphene and B-, N-, O-, Si-, P-, and S-doped graphene by first-principles calculations based on density functional theory. We found that localized orbitals, which can trap Pt atoms, are created in the vicinity of dopants. Thus, these doped graphene supports prevent Pt atom desorption. In particular, O- and P-doped graphene showed adsorption energies of −3.93 and −3.59 eV, respectively, while that of pristine graphene is −1.45 eV. We also calculated the diffusion coefficients of Pt atoms on these doped graphene at 100 °C, which is a typical operating temperature of polymer electrode fuel cells. The obtained diffusion coefficients of Pt atoms on doped graphene were less than that on pristine graphene. The diffusion coefficient on P-doped graphene was 10^–30 less than that on pristine graphene. However, the activation barriers for diffusion toward dopants were almost same as those on pristine graphene, which means that Pt atoms can easily move and become trapped at dopant sites.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b01241

DOI: 10.1021/acs.jpcc.7b01241