Crucial Roles of Electron–Proton Transport Relay in the Photosystem II-Photocatalytic Hybrid System for Overall Water Splitting

Abstract

Redox shuttle reaction plays a crucial role in electron and proton transfer process of natural and artificial photosynthesis for the solar-to-chemical energy conversion. In nature, photosynthetic electron transfer is delivered efficiently by the elaborated redox cofactors for generation of the reducing equivalents. However, efficient electron/proton transport is still a challenge to couple the natural and artificial photosynthetic system. Herein, we demonstrate a hybrid photosystem in conjugation of plant photosystem II (PSII) and inorganic Ru/SrTiO3:Rh (Rh-doped) photocatalyst with quinone–ferricyanide relay for overall water splitting reaction under visible light irradiation. Electrons and protons from natural PSII to artificial photocatalyst by a quinone molecule are transported at the bioinorganic interface. Furthermore, the quinone–ferricyanide transport relay is found to be much more efficient in enhancement of the water splitting activity. This work makes it possible to construct the hybrid photosy...