Microfluidic Continuous Synthesis of Size- and Facet-Controlled Porous Bi₂O₃ Nanospheres for Efficient CO₂ to Formate...

Bismuth-based catalysts are effective in converting carbon dioxide into formate via electrocatalysis. Precise control of the morphology, size, and facets of bismuth-based catalysts is crucial for achieving high selectivity and activity. In this work, an efficient, large-scale continuous production strategy is developed for achieving a porous nanospheres Bi₂O₃-FDCA material. First-principles simulations conducted in advance indicate that the Bi₂O₃ (111)/(200) facets help reduce the overpotential for formate production in electrocatalytic carbon dioxide reduction reaction (ECO₂RR). Subsequently, using microfluidic technology and molecular control to precisely adjust the amount of 2, 5-furandicarboxylic acid, nanomaterials rich in (111)/(200) facets are successfully synthesized. Additionally, the morphology of the porous nanospheres significantly increases the adsorption capacity and active sites for carbon dioxide. These synergistic effects allow the porous Bi₂O₃-FDCA nanospheres to stably operate for 90 h in a flow cell at a current density of ≈250 mA cm^{- 2}, with an average Faradaic efficiency for formate exceeding 90%. The approach of theoretically guided microfluidic technology for the large-scale synthesis of finely structured, efficient bismuth-based materials for ECO₂RR may provide valuable references for the chemical engineering of intelligent nanocatalysts.