Promoting ethylene production over a wide potential window on Cu crystallites induced and stabilized via current...

Electrochemical CO₂ reduction (CO₂RR) in a product-orientated and energy-efficient manner relies on rational catalyst design guided by mechanistic understandings. In this study, the effect of conducting support on the CO₂RR behaviors of semi-conductive metal-organic framework (MOF) - Cu₃(HITP)₂ are carefully investigated. Compared to the stand-alone MOF, adding Ketjen Black greatly promotes C₂H₄ production with a stabilized Faradaic efficiency between 60-70% in a wide potential range and prolonged period. Multicrystalline Cu nano-crystallites in the reconstructed MOF are induced and stabilized by the conducting support via current shock and charge delocalization, which is analogous to the mechanism of dendrite prevention through conductive scaffolds in metal ion batteries. Density functional theory calculations elucidate that the contained multi-facets and rich grain boundaries promote C-C coupling while suppressing HER. This study underlines the key role of substrate-catalyst interaction, and the regulation of Cu crystalline states via conditioning the charge transport, in steering the CO₂RR pathway.