Co3O4 arrays with tailored morphology as robust water oxidation and urea splitting catalyst

Abstract A typical hydrothermal preparation approach was successfully exploited and designed for the in situ growth of highly ordered Co3O4 nanostructure precursors on a Ni foam substrates, a series of Co3O4 nanoarray-based electrocatalysts was obtained via a subsequent calcination procedure. The formation of Co3O4 hierarchical structures with different morphologies depended upon the hydrothermal time, which was used to further reveal the growth mechanism of the Co3O4 nanostructures. H2O and CO(NH2)2 were selected as probe molecules to evaluate the electrocatalytic activity over the resulting Co-based electrocatalysts, and the influence of the morphology on the electrocatalytic performance was further investigated via employing different hydrothermal times. It is worth noting that Co3O4/NF-11h nanosheets@nanoneedles heterostructures with a low density of nanosheets presents superior electrocatalytic performance and long-term durability owing to an increased exposure to active sites in the hierarchical nanostructure. The Density Functional Theory (DFT) calculations results show that H2O molecules are preferentially adsorbed at the top of the Co3O4 (111) crystal surface. This work emphasizes the significance of effective structure design for the development of robust and precious metal-free electrocatalysts via the precise control of catalyst morphology.