Highly selective electrocatalytic reduction of CO2 to HCOOH over an in situ derived hydrocerussite thin film on a Pb substrate

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

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.

Controlling the Size and Porosity of Sodalite Nanoparticles from Indonesian Kaolin for Pb2+ Removal

Mesoporous sodalite nanoparticles were directly synthesized from Indonesian kaolin with the addition of CTABr as a mesopore template. The studies highlighted the importance of aging time (3–12 h) and temperature (50–80 °C) on increasing surface area and mesoporosity of sodalite. Indonesian kaolin was used without pre-treatment and transformed to sodalite following the initial molar composition of 10 Na₂O: 2 SiO₂: Al₂O₃: 128 H₂O. Characterization data revealed the formation of high surface area sodalite with mesoporosity at increasing aging temperatures and times. The presence of CTABr as templates produced sodalites nanoparticles with smaller aggregates than the non-template sodalite. The sodalite sample obtained at 80 °C of crystallization temperature for 9 h (S80H9) displayed the highest mesopore volume (0.07612 cm³/g) and the highest adsorption capacity of Pb²⁺ (212.24 mg/g). Pb²⁺ was suggested to adsorb via ion exchange with the Na⁺ counter cation and physical adsorption.

Efficient and Selective CO2 Reduction to Formate on Pd-Doped Pb3 (CO3 )2 (OH)2 : Dynamic Catalyst Reconstruction and Accelerated CO2 Protonation

Exploring catalyst reconstruction under the electrochemical condition is critical to understanding the catalyst structure-activity relationship as well as to design effective electrocatalysts. Herein, a PbF₂ nanocluster is synthesized and its self-reconstruction under the CO₂ reduction condition is investigated. F^- leaching, CO₂ -saturated environment, and application of a cathodic potential induce self-reconstruction of PbF₂ to Pb₃ (CO₃ )₂ (OH)₂ , which effectively catalyze the CO₂ reduction to formate. The in situ formed Pb₃ (CO₃ )₂ (OH)₂ discloses >80% formate Faradaic efficiencies (FEs) across a broad range of potentials and achieves a maximum formate FE of ≈90.1% at -1.2 V versus reversible hydrogen electrode (RHE). Kinetic studies show that the CO₂ reduction reaction (CO₂ RR) on the Pb₃ (CO₃ )₂ (OH)₂ is rate-limited at the CO₂ protonation step, in which proton is supplied by bicarbonate (HCO₃ ^- ) in the electrolyte. To improve the CO₂ RR kinetics, the Pb₃ (CO₃ )₂ (OH)₂ is further doped with Pd (4 wt%) to enhance its HCO₃ ^- adsorption, which leads to accelerated protonation of CO₂ . Therefore, the Pd-Pb₃ (CO₃ )₂ (OH)₂ (4 wt%) reveals higher formate FEs of >90% from -0.8 to -1.2 V versus RHE and reaches a maximum formate FE of 96.5% at -1.2 V versus RHE with a current density of ≈13 mA cm^-2 .