The importance of target product engineering for long-term operation of CO2 zero-gap electrolysers

Zero-gap electrolysers lead the race for industrial implementation in the electrosynthesis of carbon-based products from waste CO2. Due to their compact structure, these reactors have lower ohmic losses and attain higher energy efficiencies than the alternatives. However, most research conducted on these electrochemical cells dismisses key product-specific considerations. In this work, we optimised a zero-gap system and tuned it for the production of both formate and carbon monoxide. We assessed the industrial applicability of alternative metal-nitrogen-doped carbon catalysts and benchmarked them with state-of-the-art metallic nanoparticles. We achieved energy efficiencies as high as 50.4% for the production of HCOO- and 58.0% for the production of CO (86.9 mA cm(-2)). Finally, a rapid degradation study was conducted for start-stop operation, which revealed the current challenges of this novel family of catalysts. This study constitutes an essential step in the direction of upscaled zero-gap CO2 electrolysis with metal-nitrogen-doped carbon catalysts.