Mechanistic Studies of Pyridine Catalyzed CO2 Reduction on Pt Electrodes: An Electrochemical Surface Science Approache

• Applicant: Professorin Dr. Katharina Krischer
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation ; Solid State and Surface Chemistry, Material Synthesis ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 319495763

The storage of energy is a major challenge accompanying the increasing use of renewable energy resources in the 21st century. To store electrical energy in form of chemical energy in liquid or gaseous hydrocarbons with CO2 as feedstock is obviously appealing, and one possible route is the electrochemical reduction of CO2 in aqueous electrolytes. Yet, most electrocatalysts require a high overvoltage and either lead to the less desirable products CO or formic acid or to a mixture of the various possible reduction products. An exception is the pyridine catalyzed electrochemical reduction of CO2, which proceeds at rather low overvoltage with the primary product methanol. However, the mechanism of the electrocatalytic process is still unclear, which hampers its further optimization towards technical application.We intend to use a surface science electrochemical approach to investigate the key reaction steps in a systematic way. Therefor, we will first investigate the adsorption of pyridine from Ar-saturated electrolytes on polycrystalline Pt and the three low-indexed Pt single crystal surfaces with surface sensitive infrared spectroscopic techniques as well as electrochemical methods. Then, we will repeat these studies with CO2 dissolved in the electrolyte. Furthermore, CO2 reduction products will be analyzed with differential electrochemical mass spectrometry (DEMS), as well as gas (GC) and liquid (HPLC) chromatography. Additionally, the effect of different supporting electrolytes will be investigated. Lastly, we will study the stability of pyridine towards electrochemical reduction using DEMS as well as HPLC. The final goal of these studies is to deduce a comprehensive reaction mechanism for the pyridine catalyzed CO2 reduction at platinum electrodes.

• DFG Programme: Research Grants