In-situ grafting of cobalt phthalocyanine on gas diffusion electrodes enables ampere-level CO2 reduction

Immobilizing molecular catalysts onto gas diffusion electrodes (GDEs) through covalent bonds provides a strategy to circumvent their issues of aggregation, detachment and poor conductivity during CO₂ electrolysis. However, this approach has been limited to catalysts equipped with specially designed functional groups, and directly covalent grafting of pristine molecular catalysts onto GDEs remains a formidable challenge. Herein, using pristine cobalt phthalocyanine (CoPc) as a model catalyst, we propose a polypyrrole (ppy) mediated electro-polymerization strategy that creates robust C-C bonds between GDEs and pristine CoPc. In this scheme, ppy acts as both the conductive linker and scaffold for pristine CoPc, and its electron donation effects further enhances the CO₂ electrolysis activity of CoPc centres. Here we show that the assembled CO₂ electrolyzer using CoPc/ppy/GDE electrode achieves stable operation for 120 h at 500 mA cm^-2 and 50 h at 1 A cm^-2 in alkaline media. When coupled with a triple-junction solar cell, the resulting photovoltaic-electrolysis system attains a solar-to-CO efficiency of 19.2%.