Lateral silicon oxide/gold interfaces enhance the rate of electrochemical hydrogen evolution reaction in alkaline media
| Autor: | Thomas Maier, Simon Mendisch, Katharina Krischer, Matthias Golibrzuch, Werner Schindler, Markus Becherer |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
010304 chemical physics Silicon technology industry and agriculture Oxide General Physics and Astronomy chemistry.chemical_element Electrolyte 010402 general chemistry Electrochemistry 01 natural sciences 0104 chemical sciences Metal chemistry.chemical_compound chemistry Chemical engineering visual_art 0103 physical sciences Electrode visual_art.visual_art_medium Water splitting Physical and Theoretical Chemistry Silicon oxide |
| Zdroj: | The Journal of chemical physics. 152(15) |
| ISSN: | 1089-7690 |
| Popis: | The production of solar hydrogen with a silicon based water splitting device is a promising future technology, and silicon-based metal–insulator–semiconductor (MIS) electrodes have been proposed as suitable architectures for efficient photocathodes based on the electronic properties of the MIS structures and the catalytic properties of the metals. In this paper, we demonstrate that the interfaces between the metal and oxide of laterally patterned MIS electrodes may strongly enhance the catalytic activity of the electrode compared to bulk metal surfaces. The employed electrodes consist of well-defined, large-area arrays of gold structures of various mesoscopic sizes embedded in a silicon oxide support on silicon. We demonstrate that the activity of these electrodes for hydrogen evolution reaction (HER) increases with an increase in gold/silicon oxide boundary length in both acidic and alkaline media, although the enhancement of the HER rate in alkaline electrolytes is considerably larger than in acidic electrolytes. Electrodes with the largest interfacial length of gold/silicon oxide exhibited a 10-times larger HER rate in alkaline electrolytes than those with the smallest interfacial length. The data suggest that at the metal/silicon oxide boundaries, alkaline HER is enhanced through a bifunctional mechanism, which we tentatively relate to the laterally structured electrode geometry and to positive charges present in silicon oxide: Both properties change locally the interfacial electric field at the gold/silicon oxide boundary, which, in turn, facilitates a faster transport of hydroxide ions away from the electrode/electrolyte interface in alkaline solution. This mechanism boosts the alkaline HER activity of p-type silicon based photoelectrodes close to their HER activity in acidic electrolytes. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|