Investigating the synergistic effect of Nafion and electrolyte on the electrochemical CO2 reduction for sustainable C2H4 production

Plastics are ubiquitous materials in modern society, covering a broad range of applications. Most technologically relevant polymers (polyethylene, polypropylene, polystyrene, polyvinyl chloride, etc.) are produced starting from ethylene. As this key platform chemical is primarily obtained from fossil sources, the current production of plastics is entirely non-renewable. Moreover, incineration is usually the final step in the lifetime of plastics, with the combustion product, CO2, being released into the atmosphere. It is thus essential to develop technologies able to recycle these important materials, and to offer greener alternatives to fossil-fuel-based ethylene. Here, the conversion of detrimental CO2 emissions into renewable ethylene has been identified as a key step towards the full recyclability of polymers, and to the achievement of a circular carbon economy1. Among the various technologies under development, the electrochemical CO2 reduction (eCO2R) offers the unique possibility of directly coupling CO2 conversion with renewable electricity. To ensure the industrial applicability of eCO2R, electrodes need to be highly active, selective, stable, and scalable. To meet these targets, the architecture of the electrode must provide an adequate catalyst environment, e.g. by maximizing the availability of CO2 while simultaneously controlling H2O access, to minimize the parasitic H2 evolution reaction. Recently, the use of gas diffusion electrodes (GDEs) has enabled a substantial increase in CO2 transport to the catalyst compared to the canonical immersion geometry, so that technological relevant current densities (≥ 200 mA/cm2) can be routinely achieved.