Proton feeding from defect-rich carbon support to cobalt phthalocyanine for efficient CO2 electroreduction

Abstract

Electrocatalytic CO₂ reduction reaction (CO₂RR) holds significant promise for sustainable energy conversion, with cobalt phthalocyanine (CoPc) emerging as a notable catalyst due to its high CO selectivity. However, CoPc's efficacy is hindered by its limited ability to provide sufficient proton for the protonation process, particularly at industrial current densities. Herein, we introduce defect-engineered carbon nanotubes (d-CNT) to augment proton feeding for CO₂RR over CoPc, achieved by expediting water dissociation. Our kinetic measurements and in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy reveal d-CNT significantly enhances proton feeding, thereby facilitating CO₂ activation to *COOH in CoPc. Density functional theory calculations corroborate these findings, illustrating that d-CNT decreases the barrier to water dissociation. Consequently, the CoPc/d-CNT mixture demonstrates robust performance, achieving 500 mA cm^–2 for CO₂RR with CO selectivity exceeding 96%. Notably, CoPc/d-CNT remains stability for a duration of 20 h under a substantial current density of 150 mA cm^–2. The study broadens the scope of practical applications for molecular catalysts in CO₂RR, marking a significant step towards sustainable energy conversion.