Graphene-like holey Co3O4 nanosheets as a highly efficient catalyst for oxygen evolution reaction

• Graphene-like holey Co3O4 nanosheets are prepared via a bottom-up self-assembly approach.
• The atomic thickness and mesoporosity provide numerous low-coordinated surface atoms.
• The lattice structural distortion leads to the redistribution of surface electron density.
• The Co3O4 nanosheets exhibit high catalytic activity towards oxygen evolution reaction.