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

By Yan, Kai-Li; Chi, Jing-Qi; Xie, Jing-Yi; Dong, Bin; Liu, Zi-Zhang; Gao, Wen-Kun; Lin, Jia-Hui; Chai, Yong-Ming; Liu, Chen-Guang
Published in Renewable Energy 2018

Abstract

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.

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