Porous oxide electrocatalysts for oxygen evolution reaction prepared through a combination of hydrogen bubble templated deposition, oxidation and galvanic displacement steps

Porous oxide layers active in the oxygen evolution reaction (OER) were prepared with the following sequence of steps: (i) porous Pb was produced by cathodic hydrogen bubble templated electrodeposition; (ii) Pb was partially converted to its oxides; (iii) Co3O4 shells were formed on the surface of lead/lead oxides nanowires by spontaneous galvanic displacement reactions. The effect of deposition current density and charge on the porous Pb morphology was studied. Deposits with extended surface areas were obtained and then oxidized in neutral Na2SO4 solutions. Pb and PbO2, initially coexisting in oxidized samples, underwent a spontaneous reaction leading to the formation of Pb3O4. Both PbO2 and Pb3O4 spontaneously reacted with Co2+ to yield Co3O4 layers. Co-modified electrodes described in this work had higher activity in oxygen evolution reaction (OER) than those obtained by submitting to galvanic displacement porous PbO2 layers prepared by oxygen bubble templated anodic deposition.