Self-pressurizing nanoscale capsule catalysts for CO2 electroreduction to acetate or propanol

The selective one-step CO2 electroreduction reaction (CO2RR) to acetate and propanol has garnered intense interest. Here we report the design of self-pressurizing nanoscale capsule catalysts for the CO2RR. A high-pressure CO intermediate environment is created around copper catalysts by a permselective enclosure. Microkinetic modelling, 13CO2/12CO co-feed experiments and in situ Raman spectroscopy confirm that a unique CO–CO2 coupling path is involved, which is only initiated at high CO intermediate pressure. This pathway benefits acetate production due to the kinetic and energetic advantages of COCO2*. The acetate Faradaic efficiency is 38.5 ± 2.2% (8 times higher than that achieved without enclosure) and the acetate partial current density is 328 ± 19 mA cm−2, which surpasses the performance of previous CO2RR catalysts. In situ investigation indicates that the CO pressure inside the nanoscale capsule catalysts can reach 8 ± 3 bar. Furthermore, self-pressurizing nanoscale capsule catalysts with a CuI-derived core can reduce CO2 to propanol with a Faradaic efficiency of 25.7 ± 1.2% and a conversion rate of 155 ± 3 mA cm−2. CO2 electroreduction to multicarbon products is desirable but challenging. Now, self-pressurizing nanoscale capsule catalysts are synthesized. The self-pressurising capsules harness high-pressure CO environments for selective acetate or propanol production via a CO–CO2 coupling pathway.