Porous Copper Microspheres for Selective Production of Multicarbon Fuels via CO2 Electroreduction

The electroreduction of carbon dioxide (CO₂) toward high‐value fuels can reduce the carbon footprint and store intermittent renewable energy. The iodide‐ion‐assisted synthesis of porous copper (P‐Cu) microspheres with a moderate coordination number of 7.7, which is beneficial for the selective electroreduction of CO₂ into multicarbon (C₂₊) chemicals is reported. P‐Cu delivers a C₂₊ Faradaic efficiency of 78 ± 1% at a potential of ?1.1 V versus a reversible hydrogen electrode, which is 32% higher than that of the compact Cu counterpart and approaches the record (79%) reported in the same cell configuration. In addition, P‐Cu shows good stability without performance loss throughout a continuous operation of 10 h.