Nanoporous bismuth for the electrocatalytic reduction of CO2 to formate

Bi is an attractive catalyst towards the electrochemical reduction of CO2 to formate. In this work, nanoporous bismuth was prepared by dealloying Mg3Bi2 with tartaric acid (TA) solution, and the size of the primary Bi nanoparticles was adjusted according to the concentration of TA. When the concentration of TA increased from 2 wt% to 20 wt%, the particle size of Bi increased from about 70 nm to 400 nm. The synthesized nanoporous Bi samples were investigated as electrocatalysts for the reduction of CO2 in KHCO3 electrolyte, and it was found that the smaller the particle size, the higher the catalytic activity. However, nanoporous Bi comprising 70 nm particles suffered from mass transfer difficulty and sintering during the reaction, whereas the 100 nm nanoporous Bi delivered both a high formate formation current and faradaic efficiency (FE) (16 mA cm(-2), FE > 90% at -0.88 V vs. RHE) and showed excellent durability.

Automated summary

In this study, nanoporous bismuth was prepared by dealloying Mg3Bi2 with tartaric acid solution, and the size of bismuth nanoparticles was found to influence catalytic activity for CO2 reduction. Smaller bismuth nanoparticles showed higher catalytic activity, with 100 nm nanoporous bismuth demonstrating excellent performance in terms of formate formation current and efficiency.