High performance of homo-metallic tetracyanonickelate based coordination polymer towards water oxidation electrocatalysis

•The polymeric compound [{NiII(4,4ʹ-dipy)4}{Ni(CN)4}]n (1) is presented as electrocatalyst towards water oxidation.•1 has showed ca. 28 times enhanced surface concentration (Γ = 39.5 nmol/cm2), compared to the reported CoFe(CN)6 (Γ = 1.4 ± 0.2 nmol/cm2).•The overpotential of merely 315 mV is required to produce a current density of 1 mA/cm2.•The development is designing the noble metal (Pt/Ru/Ir) free, efficient electrocatalysts for water oxidation reaction.