Oxygen reduction reaction on Fe doped Cu oxide electrodes

The work presents an investigation into Fe-doped CuOx (Cu[Fe]Ox/Au) catalysts, expanding on the previous studies of transition metal-doped CuOx systems for the oxygen reduction reaction (ORR). While Cu[Fe]Ox/Au does not exhibit the same level of enhancement as Cu[Co]Ox, Cu[Ni]Ox, or Cu[Mn]Ox, it still demonstrates notable improvements over its pure-phase counterparts, particularly in enhanced ORR currents and reduced H2O2 formation. This reinforces the broader hypothesis that transition metal doping into CuOx enhances catalytic efficiency, even when the extent of improvement varies among different dopants. A key mechanistic insight from this study is the distinct behavior of Cu[Fe]Ox/Au in H2O2 reduction. Unlike other Cu[M]Ox electrodes, where O2 and H2O2 reduction seem to occur at the same active sites, Cu[Fe]Ox/Au exhibits H2O2 reduction currents more similar to pure CuOx/Au, suggesting that O2 and H2O2 reduction might occur at separate catalytic sites.