Methanol Tolerant Oxygen Reduction Reaction Electrocatalysis using Size‐Specific Triphenylphosphine‐Ligated Gold Nanoclusters

Abstract The development of a stable and efficient Oxygen Reduction Reaction (ORR) electrocatalysts with high methanol tolerance is crucial for Direct Methanol Fuel Cells (DMFCs). Herein, triphenylphosphine (PPh₃)‐ligated gold nanoclusters and complexes (AuNCs), Au₁₀₁(PPh₃)₂₁Cl₅, Au₉(PPh₃)₈(NO₃)₃, and Au₁(PPh₃)Cl supported on reduced graphene oxide (rGO) have been explored as methanol tolerant ORR electrocatalysts. Electrocatalytic performance of each AuNCs‐rGO was determined through linear sweep voltammograms (LSV) and cyclic voltammetry (CV) and compared with Pt/C. Size‐dependent ORR activity was observed which followed the size trend of Au₁₀₁NC‐rGO>Au₉NC‐rGO>Au₁NC‐rGO. Repeated LSV and chronoamperometry measurements revealed that the long‐term stability over 24 hours followed the trend Au₁₀₁NC‐rGO>Au₉NC‐rGO∼Au₁NC‐rGO and all were more stable than Pt/C. The methanol tolerance of each AuNCs‐rGO was also evaluated via LSV and CV. Size‐independent methanol tolerance with no noticeable change in ORR performance of AuNCs‐rGO was observed in the presence of methanol. AuNCs‐rGO nanocomposites are promising cathode electrocatalysts for DMFCs.