Conductive phthalocyanine-based metal-organic framework as a highly efficient electrocatalyst for carbon dioxide reduction reaction

Porous crystalline metal-organic frameworks(MOFs)are one class of promising electrode materials for CO_(2)electroreduction reaction(CO_(2)RR)by virtue of their large CO_(2)adsorption capacities and abundant tunable active sites,but their insulating nature usually leads to low current density.Herein,a two-dimensional(2D)Ni-phthalocyanine-based MOF(NiPc-Ni(NH)4)constructed by 2,3,9,10,16,17,23,24-octaaminophthalocyaninato nickel(II)(NiPc-(NH_(2))_(8))and nickel(II)ions attained high electrical conductivity due to the high overlap of d-πconjugation orbitals between the nickel node and the Ni-phthalocyanine-substituted o-phenylenediamine.During CO_(2)RR,the NiPc-Ni(NH)4 nanosheets achieved a high CO Faradaic efficiency of 96.4%at−0.7 V and a large CO partial current density of 24.8 mA cm^(−2)at−1.1 V,which surpassed all the reported two-dimensional MOF electrocatalysts evaluated in an H-cell.The control experiments and density functional theory(DFT)calculations suggested that the Ni-N_(4)units of the phthalocyanine ring are the catalytic active sites.This work provides a new route to the design of highly efficient porous framework materials for the enhanced electrocatalysis via improving electrical conductivity.