Hollow Porous Carbon Nanocubes with High-Loading Accessible Iron Atomic Sites for CO2 Electroreduction

Single-atom catalysts (SACs) have exhibited enormous potential toward electrocatalytic CO2 reduction (CO2RR). The accessibility of active sites has a significant influence on their catalytic performance, especially in the mass-transport-limited catalytic reaction like CO2RR. Therefore, the rational design of SACs with easily accessible and high-loading atomic sites is crucial but still remains a grand challenge. In this work, a thermally removable template strategy combined with emulsion-induced interface anisotropic assembly method was developed to prepare iron single-atom catalyst with easy accessibility and high loading amount. For CO2RR, as-synthesized Fe-SACs supported on hollow porous carbon nanocube (H–Fe–NC SACs) display high selectivity toward CO. Most importantly, the CO partial current density of H–Fe–NC SACs at −0.98 V can reach −23.5 mA cm–2, which is 2.3 times higher than that of Fe-SACs on solid carbon sphere. The hollow and porous carbon matrix efficiently enhances the accessibility of the active sites and promotes mass transport, thus accelerating the reaction kinetics of the catalysis reaction. It is expected that this carrier engineering can provide a versatile route to improve the catalyst performance of the mass-transport-limited electrocatalytic reaction.