Abstract
High-rate CO electrosynthesis from CO(2) is vital for efficient CO(2)-CO-C(2+) tandem conversion. Cobalt phthalocyanine (CoPc), featuring a Co-N(4) site naturally favorable for CO production, suffers from low conductivity. Herein, a molecular engineering strategy is reported to construct cobalt tetra-aza-phthalocyanine (CoTAP) by incorporating four pyridinic-N atoms at the β-positions of the CoPc macrocyclic backbone, effectively enhancing both conductivity and intrinsic activity. The resulting CoTAP electrode achieves ≈100% CO selectivity at an ultralow onset overpotential of 140 mV (-0.25 V vs. RHE), significantly outperforming pristine CoPc (-0.57 V vs. RHE). Furthermore, it also delivers a record-high CO current density of -1084 mA cm(-2), an exceptional mass activity of 24,636.4 A g(-1), and an ultrahigh turnover frequency of 73.4 s(-1), with excellent stability for 112 h at -150 mA cm(-2), surpassing all reported Pc-based catalysts. Systematic analysis shows that pyridinic-N incorporation alters the electronic environment around Co centers and reduces resistance to only 3.8% of CoPc. Theoretical calculations further confirm more favorable adsorption energies for key intermediates ((*)COOH and (*)CO), underpinning the enhanced intrinsic activity. Collectively, these advancements maximize site-specific reaction kinetics in CoTAP. This work presents a molecular-level strategy to simultaneously boost conductivity and intrinsic activity for advanced CO(2) electroreduction.