Chloroplast-like porous bismuth-based core-shell structure for high energy efficiency CO₂ electroreduction

Electrochemical CO₂ reduction reaction (CO₂RR) to formate is economically viable considering the energy input and market value. Through learning nature, a series of chloroplast-like porous bismuth-based core-shell (CPBC) materials have been designed. In these materials, the porous carbon can enrich and transfer CO₂ to the core-shell Bi@Bi₂O₃ in CO₂ reduction process, during which Bi₂O₃ layer can be transformed into activated metastable layer to efficiently convert CO₂ into formate and Bi can provide abundant electrons. Based on this, superior performances for most of important parameters in CO₂RR can be achieved and best of them, CPBC-1 presents remarkable Faradaic efficiency (FE_formate > 94%) over a wide potential range (-0.65 to -1.0 V) with high catalysis durability (>72 h). Noteworthy, its maximum energy efficiency is as high as 76.7% at -0.7 V, the highest one in reported bismuth-based materials. This work opens novel perspectives in designing nature-inspired CO₂RR electrocatalysts.