文摘
A new ·CN radical molecular surface chemisorption strategy was developed to modify Pt/C electrocatalysts in a green and facile manner via a photo-Fenton cyanation process. After the surface modification, the Pt/C electrocatalysts display better specific activity for ORR and a significantly enhanced methanol (MeOH)-tolerant property in both alkline and acidic media. The experimental observations and DFT calculations suggest that the unique electrochemical performance of CN–Pt/C might be derived from the covalent nature of the interaction between ·CN and Pt surface. In particular, it hinders the formation of detrimental OHad–K+(H2O)x, CN–K+(H2O)x, or CN–Na+(H2O)x clusters on the surface of PtNPs, which could block the access of oxygen molecules. Meanwhile, the adsorption of MeOH molecules becomes more difficult as compared to unmodified Pt in KOH solution on the basis of the DFT calculations, making CN–Pt/C an efficient cathode electrocatalyst to alleviate the MeOH crossover problem in alkaline DMFCs. Interestingly, experimental results show that the steric blocking effects of CN groups also improve MeOH-tolerant property CN–Pt/C catalysts operated in acid medium. The green nature and simplicity of the current strategy can facilitate their large-scale use to modify the Pt electrocatalysts with improved performance.
