Mechanistic insight on porphyrin based porous titanium coordination polymer as efficient bifunctional electrocatalyst for hydrogen and oxygen evolution reactions

Herein, a novel porous titanium coordination polymer (TiCP-PCP) with push-pull motif is prepared through the transesterification reaction of catechol porphyrin with titanium tetraisopropoxide. TiCP-PCP demonstrates efficient electrocatalytic activity toward HER/OER with prominent electrochemical durability in acid/basic medium. Surprisingly, TiCP-PCP requires relatively low overpotentials of 339 and 310 mV to reach a catalytic current density of 10 mA cm−2 for HER and OER, respectively. Based on experimental and theoretical results, the improved electrocatalytic performances for TiCP-PCP in comparison with those of TPP and TiO2 are ascribed to efficient charge transfer and positive synergistic effect, stemming from the interactions between porphyrin units and Ti entities. This work can be readily extended to a wide range of porous coordination polymer-based electrochemical devices and catalysts design. A novel porous titanium coordination polymer with push-pull motif was designed and prepared through the transterification reaction of catechol porphyrin with titanium tetraisopropoxide. TiCP-PCP demonstrated efficient electrocatalytic activity toward HER/OER with prominent electrochemical durability in acid/basic medium. [Display omitted] •A novel porous titanium coordination polymer with push-pull motif was designed.•This polymer can provide abundant active sites for hydrogen and oxygen evolution.•The prepared polymer exhibited excellent electrocatalysis.•The improved electrocatalysis was assigned to a combination of mechanisms.