BIAN Based Electroactive Polymer with Defined Active Centers as Metal-Free Electrocatalysts for Oxygen Reduction Reaction (ORR) in Aqueous and Nonaqueous Media

We report design, synthesis, and performance evaluation of functional polymer material with defined active sites for oxygen reduction reaction (ORR) catalytic activity in aqueous as well as nonaqueous media. The BIAN-paraphenylene (BP) copolymer having an imine backbone was synthesized via solution based polycondensation. The as synthesized polymer itself showed ORR activity comparable to that of other doped carbon materials. The composites of the polymer with graphene oxide (GO) sheets (GO/BP) were also synthesized under moderate temperature conditions (400 °C) with the polymer remaining intact. The composites showed further enhanced electrochemical activity owing to the synergistic effect of GO and active site defined polymer material. We also tried to evaluate the nature and basis of catalytic activity on the polymer surface by different techniques. The cyclic voltammograms showed two distinct ORR peaks, indicating two different active sites. This was also in agreement with Mulliken charge distribution from DFT studies, which showed the presence of two different carbons next to nitrogen having different electropositive nature.