Precipitation/dissolution equilibrium to achieve trace iron doping on the surface of β-Ni(OH)2 for electrocatalytic oxygen evolution

•The doping of trace iron on β-Ni(OH)2 was realized by precipitation/dissolution equilibrium.•3D hybrid structure provides more sites for iron incorporation on the surface/edge/corner of β-Ni(OH)2.•Iron doping can expose more Fe-Ni-Fe sites and adjust the electronic structure of Ni sites.•Fe2(0.1)-β-Ni(OH)2/NF exhibits the motivated OER activity and stability.