Light-induced proton pumping with a semiconductor: vision for PhotoProton lateral separation and robust manipulation

Abstract

Energy transfer reactions are the key for living open systems, biological chemical networking and development of life inspired nanoscale machineries. It is a challenge to find simple reliable synthetic chemical networks providing a localization of the time dependent flux of matter. In this paper we introduce a reliable, minimal reagent consuming, stable inorganic light promoted proton pump. Localized illumination was applied to a TiO2 surface in solution for reversible spatially controlled “inorganic photoproton” isometric cycling, the lateral separation of water splitting reactions. The proton flux is pumped during irradiation of the surface of TiO2 and dynamically maintained at the irradiated surface area in the absence of any membrane or predetermined material structure. Moreover we spatially predetermine a transient acidic pH on the TiO2 surface in the irradiated area with feedback-driven generation of a base as deactivator. Importantly we describe, how to effectively monitor the spatial localization of the process by in situ scanning ion selective electrode technique (SIET) measurements for pH and scanning vibrating electrode technique (SVET) for local photoelectrochemical studies. This work shows the great potential for time- and space-resolved water splitting reactions for following investigation of pH stimulated processes in open systems with their flexible localization on a surface.