| Full text | |
| Author(s): |
Rodrigues Pinto, Maria
;
Vos, Rafael E.
;
Nagao, Raphael
;
Koper, Marc T. M.
Total Authors: 4
|
| Document type: | Journal article |
| Source: | Journal of Physical Chemistry C; v. 128, n. 50, p. 9-pg., 2024-12-05. |
| Abstract | |
Understanding the electrolyte factors governing the electrochemical CO2 reduction reaction (CO2RR) is fundamental for selecting the optimized electrolyte conditions for practical applications. While noble metals are frequently studied, the electrolyte effects on the CO2RR on Sn catalysts are not well explored. Here, we studied the electrolyte effect on Sn metallic electrodes, investigating the impact of electrolyte concentration, cation identity, and anion properties, and how it shapes the CO2RR activity and selectivity. The activity for formic acid and carbon monoxide increases with the cation concentration and size at mild acid conditions. In contrast, hydrogen production is not strongly influenced by the cathodic potential, electrolyte concentration, and cation size. Furthermore, we have compared the CO2RR performance at a constant cation concentration in K2SO4 (pH 4) and KHCO3 (pH 7), where we show that the reaction rate toward HCOOH and CO are minimally impacted by the anion identity on the SHE scale, while being affected by the cations in solution, which we attribute to the reaction being limited by cation-coupled electron transfer steps rather than by a proton-coupled electron transfer step. We propose that the HCOOH forms via adsorbed hydrides leading to *OCHO intermediate, while CO forms through an electron transfer step, producing *CO2 delta-. Cations facilitate both processes by stabilizing the negatively charged intermediates, and the difference in the extent of the promotion of HCOOH over CO formation would stem from the stronger cation effects on *H compared with *CO2 delta- species. Additionally, the presence of HCO3- at high concentrations (1.0 mol L-1) is shown to significantly enhance the production of H-2 at high overpotentials (>-1.0 V vs RHE) due to bicarbonate ions acting as protons donors, outcompeting water reduction. These findings underscore the significance of electrolyte engineering for enhanced formic acid synthesis, offering valuable insights for optimizing the CO2RR processes on Sn electrocatalysts. (AU) | |
| FAPESP's process: | 19/08244-2 - Synthesis of nanowires for application in the reduction reaction of carbon dioxide |
| Grantee: | Maria Rodrigues Pinto |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 21/08868-6 - Tandem dissipative electrodes applied in the reduction of carbon dioxide to the formation of C2+ products |
| Grantee: | Raphael Nagao de Sousa |
| Support Opportunities: | Program for Research on Bioenergy (BIOEN) - Regular Program Grants |
| FAPESP's process: | 22/03750-0 - Cation effect on Sn and Bi electrodes during CO2 reduction reaction under well-defined mass transport conditions |
| Grantee: | Maria Rodrigues Pinto |
| Support Opportunities: | Scholarships abroad - Research Internship - Doctorate |
| FAPESP's process: | 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country |
| Grantee: | Ana Flávia Nogueira |
| Support Opportunities: | Research Grants - Research Centers in Engineering Program |