Construction of hydrophilic-and-cationic metalloporphyrin-based polymers for electrocatalytic small molecule activation

The electrocatalytic activation of small molecules for the production of hydrogen, oxygen, and ammonia represents a novel approach towards achieving environmentally sustainable chemical transformations. Covalent organic polymers have attracted extensive research due to their designable structures and well-defined catalytic sites. Herein, we elaborate on the synthesis, characterization, and electrochemical analyses of a class of hydrophilic and cationic polymers (M-MV) with metalloporphyrins serving as the active central nodes. Owing to the inclusion of cationic viologen units, the as-prepared M-MV exhibited excellent hydrophilicity. When the metal centres vary, three metalloporphyrin-based covalent polymers possess specific catalytic properties for distinct electrocatalytic reactions in aqueous solution. The experimental results show that Co-MV is more favorable for the electrocatalytic HER, Ni-MV is more conducive to the electrocatalytic OER, and Cu-MV exhibits the optimal catalytic activity in the electrocatalytic NO₂^-RR.