• Energy Research

International audience The CO2 reduction reaction using a renewable energy source is a promising strategy for its utilization. Such a technology however requires the development of catalysts with optimized activity and selectivity that can be integrated into the device architectures. Flow electrolyzers have recently been proposed for facilitating the electrochemical CO2 reduction reaction thanks to their unique ability to perform electroreduction at high reaction rates via the creation of three-phase interface. While some examples of flow electrolyzers for the conversion of CO2 has recently been reported, the influence of the CO2 and electrolyte streams on the overall catalytic mechanism is remained ambiguous. Here, we synthesized single-atom nickel on two-dimensional nitrogen-doped carbon nanosheets (SA Ni-NC) for the CO2-to-CO conversion. Taking advantage of this model catalyst, we explored the correlation between the applied potential and the feeds in both