Exploration of Long-Life Pt/Heteroatom-Doped Graphene Catalysts in Hydrogen Atmosphere

We investigated the H and H₂ adsorption effects on the stability of a Pt atom on various heteroatom-doped graphene supports using first-principles calculations based on density functional theory. We show that H and H₂ adsorptions on the Pt atom weaken the interaction between the Pt atom and graphene support and decrease the adsorption energy of Pt atoms. H₂ adsorption on Pt atoms decreases the adsorption energy of Pt atoms on all graphene supports by more than 30%, whereas H adsorption only affects pristine, O-, and S-doped graphene. These results indicate that the hydrogen atmosphere enhances the detachment of Pt catalysts. However, the B-, O-, Si-, P-doped, and monovacant graphene still maintained large adsorption energies of PtH and PtH₂ of more than 1.5 eV. In addition, the diffusion barriers of PtH and PtH₂ on pristine graphene were calculated to be less than 0.07 eV, which further demonstrated that H and H₂ enhance the degradation of Pt catalysts. Even after H and H₂ adsorptions on a Pt atom, O-, Si-, P-doped, and monovacant graphene still maintained large diffusion barriers of more than 1 eV. Therefore, we concluded that O-, Si-, and P-doped graphene are suitable supports for Pt catalysts in a hydrogen atmosphere.