Graphite conjugated nickel phthalocyanine for efficient CO2 electroreduction and Zn–CO2 batteries

Abstract

The linking chemistry between molecular catalysts and substrates is a crucial challenge for enhancing electrocatalytic performance. Herein, we elucidate the influence of various immobilization methods of amino-substituted Ni phthalocyanine catalysts on their electrocatalytic CO₂ reduction reaction (eCO₂RR) activity. A graphite-conjugated Ni phthalocyanine, Ni(NH₂)₈Pc-GC, demonstrates remarkable electrocatalytic performance both in H-type and flow cells. In situ infrared spectroscopy and theoretical calculations reveal that the graphite conjugation, through strong electronic coupling, increases the electron density of the active site, reduces the adsorption energy barrier of *COOH, and enhances the catalytic performance. As the cathode catalyst, Ni(NH₂)₈Pc-GC also displays remarkable charge–discharge cycle stability of over 50 hours in a Zn–CO₂ battery. These findings underscore the significance of immobilization methods and highlight the potential for further advancements in eCO₂RR.