Flowing CO ₂ boosts a molecular catalyst Molecular electrocatalysts for CO ₂ reduction have often appeared to lack sufficient activity or stability for practical application. Ren et al. now show that design of the surrounding electrochemical cell can substantially boost both features. They directly exposed a known molecular catalyst, cobalt phthalocyanine, to gaseous CO ₂ in a flow cell architecture, rather than an aqueous electrolyte. The configuration accommodated current densities exceeding 150 milliamperes per square centimeter, with longevity limited by local proton concentration rather than catalyst stability. Science , this issue p. 367