Novel integrated strategies toward efficient and stable unassisted photoelectrochemical water splitting

Unassisted photoelectrochemical (PEC) water splitting for hydrogen evolution has been regarded as a sustainable route for the harvest and utilization of solar energy. To achieve such unassisted PEC water splitting, two novel integrated strategies have been developed: to design tandem structures of photoanodes/photocathodes and to construct hybrid devices of solar/PEC cells. Some key unsolved problems, however, still limit the further development of high-performance unassisted PEC water splitting, such as low efficiency, poor stability, and high cost. Herein, we present a brief summary of the latest development in this area and propose perspectives for further enhancing this state-of-the-art solar-to-hydrogen conversion technology, including all-metal oxide photoelectrodes, nanoarray design, surface modification, device coupling, monolithic configuration, and multi integration. (c) 2020 Published by Elsevier B.V.