Oxygen reduction at platinum- and gold-coated iron, cobalt, nickel and lead deposits on glassy carbon substrates

Platinum- and gold-coated iron, cobalt, nickel and lead particles deposited on glassy carbon electrode substrates have been tested for oxygen reduction in acid solutions. Fe, Co, Ni or Pb layers were electrodeposited onto glassy carbon and subsequently immersed into chloroplatinic or chlorolaurate acid solutions where the spontaneous surface exchange of M (M = Fe, Co, Ni or Pb) for Pt or Au resulted in Pt(M)/GC and Au(M)/GC electrodes. The bimetallic deposits displayed typical Pt and Au surface electrochemistry indicating the formation of a continuous noble metal shell over a non-precious metal-containing core. The activity of the Pt(M)/GC and Au(M)/GC towards oxygen reduction in acid was studied by voltammetry at a rotating disc electrode and compared to that of bulk Pt or Au and Pt(Cu)/GC or Au(Cu)/GC (reported previously). Interpretation of the results is based on the metal M electronic effect on the Pt or Au shell.