Voltage- and pH-driven evolution of multi-pathway C–C coupling in CO2 electroreduction on copper

Abstract

Reducing CO₂ into high-energy-density multi-carbon products is critical for addressing climate and energy challenges, with copper being the only metal capable of catalyzing this transformation. However, the fundamental mechanisms of C–C coupling on copper surfaces remain elusive. Previous models have primarily focused on *OC–CO and *OC–COH coupling steps, lacking the dynamic and comprehensive perspective towards the whole system. Addressing this gap, our microkinetic modeling systematically investigates how environmental factors modulate multi-pathway C–C coupling mechanisms. We demonstrate that voltage and pH do not simply enhance a single coupling step but dynamically regulate the accessibility and competition among multiple coupling routes, consistent with previous experimental research. These findings establish a more comprehensive understanding of C–C coupling under realistic electrochemical conditions, offering new guidance for the rational design and optimization of copper-based catalysts for sustainable multi-carbon product synthesis.