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. <i>In situ</i> 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.