Density functional theory (DFT) is used to systematically investigate the electronic structure of platinum clusters grown on different graphene substrates. Platinum clusters with 1 to 10 atoms and graphene vacancy defect supports with 0 to 5 missing C atoms are investigated. Calculations show that Pt clusters bind more strongly as the vacancy size increases. For a given defect size, increasing the cluster size leads to more endothermic energy of formation, suggesting a templating effect that limits cluster growth. The opposite trend is observed for defect‐free graphene where the formation energy becomes more exothermic with increasing cluster size. Calculations show that oxidation of the defect weakens binding of the Pt cluster, hence it is suggested that oxygen‐free graphene supports are critical for successful attachment of Pt to carbon‐based substrates. However, once the combined material is formed, oxygen adsorption is more favorable on the cluster than on the support, indicating resistance to oxidative support degradation. Finally, while highly‐symmetric defects are found to encourage formation of symmetric Pt clusters, calculations also reveal that cluster stability in this size range mostly depends on the number of and ratio between PtC, PtPt, and PtO bonds; the actual cluster geometry seems secondary.

Pristine and Defective Graphene Supports As platinum‐based materials are among the most efficient catalysts for the electrochemical processes in proton exchange membrane fuel cells, especially for the oxygen reduction reaction, several groups have shown that the support material has a major influence on the coordinative stabilization and especially on the modification of the reactivity of the Pt‐cluster‐graphene combined material. In article number 2207484, Christoph Jung, Timo Jacob, and co‐workers investigate the growth and electronic structure of platinum clusters adsorbed on pristine and defective graphene supports using density functional theory calculations.