Construction of tetrahedral CoO4 vacancies for activating the high oxygen evolution activity of Co3−xO4−δ porous nanosheet arrays

Low-crystalline Co₃O₄ porous nanosheet arrays (PNAs) with tetrahedral CoO₄ vacancies, grown on carbon fiber cloth (CFC) (Co_3−xO_4−δ PNAs/CFC), were synthesized. This unique structure endows Co_3−xO_4−δ PNAs/CFC with improved activity for the oxygen evolution reaction.