Contact-electro-catalysis at Dynamic Semiconductor–Water Junctions

Junctions are the fundamental elements of semiconductor devices, which are crucial for advancements in modern technology. However, most junctions involve static solid interfaces. Here, we studied a dynamic Schottky-like junction formed at a semiconductor–water interface, referred to as a semiconductor–water junction (SWJ), under mechanical stimulation. We found that owing to the band bending at the junction, electrons can be transferred from water molecules to p-type silicon and captured by the dissolved oxygen molecules in water periodically, resulting in abundant free radicals and catalytic capacity for degrading pollution such as methyl orange. We demonstrated that contact-electro-catalysis is the underlying mechanism, and it can be applied to various SWJs. Furthermore, by replacing water with methanol aqueous solution, hydrogen can be catalytically produced with low energy consumption. We anticipate that SWJ-stimulated contact-electro-catalysis will provide a new space for innovative catalytic strategies in the future.