K⁺ selectivity modulation in non-aqueous CO₂ electroreduction on lead catalysts: from oxalic to tartaric acid production

Author(s)

dos Reis, Eduardo Arizono ; da Silva, Gelson T. S. T. ; Ribeiro, Caue

• Document type: Journal article
• Source: JOURNAL OF MATERIALS CHEMISTRY A; v. 12, n. 26, p. 8-pg., 2024-05-21.

Abstract

Here, we show that the presence of potassium ions in the catholyte modulates the selectivity of a Pb plate electrode, leading to the formation of tartrate, a C-4 compound, from CO2 reduction. A faradaic efficiency of 60% was achieved at -2.3 V (vs. Ag/Ag+) for tartrate using a proton exchange membrane and a high concentration of potassium-based supporting anolyte. The electrode microenvironment with a higher potassium concentration also inhibits cathode corrosion and deactivation. Remarkably, the electroreduction of CO2 changes the selectivity with the cationic availability in the anolyte. Higher FE to formic acid is observed with an increase in the proton concentration, and by increasing anolyte K+ availability, C-C coupled products (oxalate, C-2, and tartrate, C-4) are formed in the majority. Our results prove that controlling potassium ions and the proton concentration in the catholyte regulates the selectivity of the Pb plate electrode and can lead to the formation of a C2+ product from CO2 reduction. (AU)

• FAPESP's process: 18/01258-5 - Novel chemical catalytic and photocatalytic processes for the direct conversion of methane and CO2 to products
• Grantee: José Maria Correa Bueno
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/10255-5 - Architectures based on metal phosphides and nitrides for photo(electro)chemical conversion of CO2 into C2+ compounds
• Grantee: Gelson Tiago dos Santos Tavares da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral