Porphyrin-Conjugated Microporous Polymer Nanospheres as Electrocatalysts for Nitrobenzene Detection and Oxygen Evolution Reaction

Using pyrrole and terephthalaldehyde as raw materials, porphyrin-conjugated microporous polymer (CMP) without metal centers in the porphyrin ring was synthesized directly via the one-step method. The polymer was carbonized at different temperatures to obtain a series of carbonaceous nanospheres C-CMP-x (x is the pyrolysis temperature), of which C-CMP-900 is a multifunctional electrochemical catalyst with excellent performance. Compared to the uncarbonized polymer, C-CMP-900 is more sensitive and efficient for the reduction of nitrobenzene and exhibits a lower limit of detection. There was a significant improvement in the performance of nitrobenzene reduction over nonmetallic catalysts described in the literature. Moreover, the catalyst also shows excellent oxygen evolution reaction (OER) electrocatalytic activity, with lower overpotential than commercial RuO2. Even after long cycling tests, the catalyst maintained good activity. The catalyst, with an ultralow detection limit for nitrobenzene reduction and excellent OER activity, may be attributed to its high specific surface area and special porous carbon structure based on the porphyrin skeleton.