Hierarchical NiCo2O4 nanosheet-decorated carbon nanotubes towards highly efficient electrocatalyst for water oxidation

The development of robust and low cost electrocatalysts with highly efficient oxygen evolution reaction capability remains a great challenge for widespread applications in water splitting. Here, spinel NiCo2O4 nanosheets grown on mildly oxidized multi-walled carbon nanotubes (CNTs) have been synthesized via a simple one-pot solution method. Compared with pure NiCo2O4, the as-prepared hierarchical NiCo2O4/CNTs composite exhibits superior OER catalytic properties, i.e. a more negative onset potential, a smaller Tafel slope and higher stability, which may be attributed to the enhanced conductivity of the hybrid, originating from the carbon nanotube substrate. Furthermore, the surface Co/Ni ratio of NiCo2O4/CNTs is changed by the synergistic reactivity between oxygen-enriched groups and metal ions, which improves the catalytic performance of NiCo2O4/CNTs. This electrocatalyst with enhanced OER performance may be a promising candidate for water splitting.