High Activity For CO2 Reduction Research Articles

Insight into the electrochemical reduction of CO2 on gold via surface-enhanced Raman spectroscopy and N-containing additives

Due to increasing levels of greenhouse gases in the atmosphere, increased attention has been given to minimizing their emissions and reducing current levels. Primarily focusing on CO2, routes towards reducing atmospheric levels include capture, sequestration, and conversion. For CO2 conversion, Au electrocatalysts have demonstrated high CO2 reduction activity to CO which can then be further converted to various synfuels or commodity chemicals. In this work, we further probe Au electrocatalysts by utilizing a Ag-based model, using N-containing additives, such as pyrazole and benzotriazole, and surface-enhanced Raman spectroscopy. Surface-enhanced Raman spectroscopy (SERS) reveals that only in the presence of N-containing additives is a stronger CO band seen. These additives do not affect the CO2 reduction mechanism of Au, as found by Tafel and product distribution analysis. We also demonstrate enhancement of the CO2 reduction rate on Au by utilizing a known CO2 scavenger, ethanolamine, adsorbed on the Au surface. This result suggests that improving CO2 reduction should focus on the reactant side of the Sabatier plot.

Electrocatalytic reduction of carbon dioxide on platinum single crystal electrodes modified with adsorbed adatoms

Platinum single crystal electrodes, Pt(hkl), represent ideal materials where studying the effect of adatoms presence in surface sensitive reactions such as carbon dioxide reduction and formic acid oxidation. In particular, we study here if some of the platinum single crystal electrodes modified with adsorbed adatoms already reported as highly active electrocatalysts for formic acid oxidation can act as bifunctional electrocatalysts and present high activity for CO2 reduction as well. After testing 12 different modified platinum single crystal electrodes, we proved by cyclic voltammetry that only Bi–Pt(111), Te–Pt(111), and Sb–Pt(100) electrodes show a significant current increase in the presence of CO2 in neutral bicarbonate buffer solution. Thus, we demonstrate their behavior as active bifunctional electrocatalysts for carbon dioxide reduction and formic acid oxidation reactions. Moreover, we provide the voltammetric fingerprint for several Bi-, Se-, Te, and Sb–Pt(hkl) electrodes in both, acid and neutral aqueous solution.