Adsorbed Carbon Monoxide-Enabled Self-Terminated Au-Grafting on Pt 6 Nanoclusters for Enhanced Methanol Electrooxidation.

The study presents the first example of an adsorbed carbon monoxide (CO) enabled self-terminated Au-grafting on triphenylphosphine (PPh 3 ) stabilized Pt 6 nanoclusters (NCs) (Pt 6 (PPh 3 ) 4 Cl 5 NCs or Pt 6 NCs). Adsorbed PPh 3 ligands weaken the Pt-CO bond enabling the self-terminated Au-grafting on Pt 6 NCs. The Au-grafted Pt 6 NCs exhibit enhanced methanol electrooxidation (MOR) in acidic solutions. The surface is composed of a PtAu ensemble exhibiting enhanced MOR and CO tolerance due to the synergistic interaction of Pt with Au and PPh 3 . The hydrogen underpotential deposition (H-UPD) signal from a CO-covered surface reveals the existence of free-Pt sites on the PtAu ensemble causing higher MOR reactivity. The Au and PPh 3 ensure electrocatalytic activity of the NCs, depriving of them at anodic potentials results in "a death-valley" trend.