Mesoporous Ag-doped Co3O4 nanowire arrays supported on FTO as efficient electrocatalysts for oxygen evolution reaction in acidic media

In acidic media, benchmark electrocatalysts for oxygen evolution reaction (OER) are mainly restricted to noble metal oxides like IrO2 and RuO2. Herein, a facile electrodeposition-hydrothermal process has been used to fabricate mesoporous Ag-doped Co3O4 nanowire arrays supported on FTO (AgCo/FTO) for water oxidation in 0.5 M H2SO4. The role of electrodeposited Ag includes: 1) Ag film on FTO can direct the vertical growth of Co3O4 to form nanowire arrays; 2) Ag2O in AgCo hydroxides precursors contribute to the formation of mesoporous nanostructure owing to the pyrolysis of Ag2O in calcination process. XRD confirms the diffraction peaks of metal Ag and Co3O4. SEM and TEM images display that mesoporous nanowire arrays of Ag-doped Co3O4 are uniformly distributed on FTO, which introduces more exposed active sites and shorter electron transfer paths. AgCo/FTO show excellent OER activity with the onset potential of 1.91 V at the current density of 10 mA cm−2. Besides, AgCo/FTO shows high stability at a constant overpotential of 370 mV for 10 h. So Ag-doping greatly enhances not only the conductivity but also the stability of electrocatalyst in acidic media. Therefore, Ag-doped transition metal oxides may be promising alternative mesoporous nanostructures for efficient OER in acid.