Donor-Acceptor Conjugated Porphyrin-Based Polymer for Excellent Hydrogen Evolution Reaction

A two-dimensional, donor-acceptor (D-A) conjugated polymer CoTEPP has been synthesized via Sonogashira coupling between the acceptor benzothiadiazole and the donor porphyrin. The resulting polymer CoTEPP exhibits good efficiency in catalyzing hydrogen evolution reaction (HER) in aqueous media, and its performance is superior to those of other porphyrin-based polymers in terms of both lower overpotentials and larger catalytic currents. CoTEPP has shown an onset potential of 355 mV for a current density of -10 mA/cm(2) and a Tafel slope of 133 mV/dec. The activity has been retained after 1500-cycle potential scans, confirming the good stability of the catalyst. The catalyst achieved a Faradic efficiency (FE) of 96% for hydrogen over 10 h. The improved performance could be attributed to the donor-acceptor pair in the structure, which facilitates electron transfer, as indicated by density functional theory (DFT) calculations. This work demonstrates an alternative strategy for designing porphyrin-based polymers with enormous potential for HER.