Electrocatalysis can use electrical power sources to accelerate chemical reactions, The interface between an (electro-)catalyst and a liquid electrocatalyte is essential to these processes. In order to understand the chemistry at these interfaces, we turn to surface-sensitive X-ray s[ectroscopy. However, air or thin layers of liquid would block the photoelectrons we wan to measure.
We tackled that problem by using an atomically thin window, namely graphene. It is transparent to the incoming radiation and the outcoming electrons. It is also an evaporation barrier, which leads to confined electrolyte, even in vacuum. With this method we now succesfully study the solid liquid interface during electrochemistry.
J. Phys. Chem. C 2019, 9146-9152
J. Am. Chem. Soc. 2019, 141, 6537-6544
The electroreduction of CO2 to valuable hydrocarbons and alcohols was investigated in accurately prepared copper oxidation states (Cu0, Cu+ and Cu2+) electrodes. By combining advanced X-ray spectroscopy and in situ micro-reactors it was found that the surface, sub-surface and bulk properties of the electrochemically prepared catalysts are dominated by the formation of copper carbonates on the surface of cupric-like oxides, which prompts catalyst deactivation by restraining effective charge transport. In addition, the formation of reduced or partially-reduced copper catalysts yields the key dissociative proton-consuming reactive adsorption.
This investigation was performed in close collaboration with the “Interface Science” department led by Prof. Roldan-Cuenya.
Ref. ACS Sus. Chem. & Eng> 2018, 7, 1485-1492