Facile and novel strategy to fabricate 2D alpha-Co(OH)2 nanosheets for efficient oxygen evolution reaction application

•2D α-Co(OH)2-NS was synthesized via a novel reduction-oxidation strategy.•The thickness of α-Co(OH)2-NS is only about 2–3 nm.•The BET surface area of the α-Co(OH)2-NS is 237.7 m2/g.•The OER activity is highly depended on the 2D structure.•The overpotential of α-Co(OH)2-NS is only 278 mV with a Tafel slope 77 mV/dec.