Gaining the Freedom of Scalable Gas Diffusion Electrodes for the CO2 Reduction Reaction

Gas diffusion electrodes (GDEs) in CO2 reduction reaction (CO2RR) alleviate the mass transfer limitation of gaseous reagents, which is beneficial for reducing CO2 into valuable chemicals. GDEs offer higher current densities compared to electrodes immersed in the electrolyte. Disclosing the roles of different structural parameters in tuning the performance of the GDEs is essential to exert the potential of catalysts and to meet potential large‐scale industrial applications of the CO2RR. A novel layer structure for the airbrush‐type spray fabrication of GDEs was designed and optimised, comprising a carbon‐based gas‐diffusion layer, a PEEK fabric, a Ni mesh, a carbon‐integrated catalyst layer, and a PTFE top layer. It was shown that adjusting the carbon material in the gas diffusion and the catalyst layer impacts the selectivity of the CO2RR due to the modulation of the pore network. This work disclosed a practical and scalable but also an easily transferable pathway for preparing GDEs and offered an idea of how to tune the significant parameters of GDEs for optimising their CO2RR performance. Scalable GDEs: A strategy to fabricate a carbon‐based asymmetrical hybrid GDE by means of airbrush‐type spray coating was proposed, comprising of a gas diffusion layer, a PEEK fabrics layer, a Ni mesh, a catalyst layer and a PTFE layer on the top. By controlling the porosity and hydrophobicity the CO2 reduction reaction (CO2RR) was substantially improved while the HER was concomitantly suppressed. The fabrication procedure was scalable and transferable.