Boosting electrocatalytic CO2 reduction to formate via carbon nanofiber encapsulated bismuth nanoparticles with ultrahigh mass activity

Electrochemical CO2 conversion is one of the most promising technologies to achieve carbon neutrality. However, it still suffers from some nonnegligible challenges on low production rate and unsatisfied current densities for potential large-scale applications. Herein, we prepare ultrasmall Bi nanoparticles uniformly encapsulated in nanofibers through electrospinning techniques, which denoted as Bi/CNFs-900. Gratifyingly, this Bi/CNFs-900 catalyst demonstrates excellent performance stability electro-reduction a broad window. Specifically, can produce formate with Faradaic efficiency over 90% high partial density –235.3 mA cm−2 at −1.23 V vs. RHE flow-cell. Furthermore, confinement effect largely restricts severe aggregation bismuth during synthesis well electrolysis procedure, greatly increases accessible active sites decreases actual mass fraction composition. Consequently, not only achieves ultrahigh activity –1.6 A mgBi−1, but also possesses an unprecedented 4403.3 μmol h−1 cm−2. DFT calculations situ Raman spectroscopy further uncover possible reaction mechanism reduction toward formate. These results could provide economical industrial-viable strategy preparation electrocatalysts reduction.