g-C3N4 /polymeric metallophthalocyanine as novel electrocatalysts for oxygen evolution reaction

In this work, non-peripherally tetra 3-(4-(4-acetylpiperazin-1-yl)phenoxy) substituted nickel(II) phthalocyanine (NiPc), cobalt(II) phthalocyanine (CoPc), zinc(II) phthalocyanine (ZnPc), copper(II) phthalocyanine (CuPc) and lead(II) phthalocyanine (PbPc) were synthesized. The structural characterization of the novel compounds was performed by a combination of instrumental methods. The electrochemical and in-situ spectroelectrochemical responses of the compounds were recorded and redox properties were illuminated. Graphitic carbon nitride(g-C3N4) was synthesized by thermal decomposition of urea and combined with metallophthalocyanines to avoid agglomeration of phthalocyanine, to obtain homogeneous microstructured catalyst and to provide synergistic effects between pyridinic N-metal bonds of g-C3N4 and metallophthalocyanines (MPcs). The synthesized compounds were electropolymerized onto g-C3N4 thanks to piperazin substitute groups. The oxygen evolution reaction (OER) of g-C3N4/Poly-MPcs was investigated in alkaline electrolyte (1 M KOH). The g-C3N4/Poly-NiPc exhibited excellent electrocatalytic performance with low overpotential and Tafel slope, respectively, 380 mV@ 10 mA cm−2 and 80 mVdec−1, which is superior to the g-C3N4. Moreover, g-C3N4/Poly-NiPc electrocatalyst exhibited ∼100 times higher current density than g-C3N4.