Bi shell-BiOI core microspheres modified TiO2 nanotube arrays photoanode: Improved effect of Bi shell on photoelectrochemical hydrogen evolution in seawater

Photoelectrochemical (PEC) seawater splitting can relive the shortage of purified water feedstocks. However, the corrosion from seawater on the photoelectrode becomes an uncertain influence factor for PEC performance. Developing an efficient and stable photoelectrode is a challenge. Herein, we present a Bi-BiOI shell-core microspheres modified TiO2 nanotube arrays (TNA) photoanode prepared via solvothermal method, affording superior PEC hydrogen evolution activity in simulated seawater under AM1.5G light, which is 3.8 and 7.6 times than those of BiOI/TNA and TNA, respectively. Solar-to-hydrogen conversion efficiency of Bi-BiOI/TNA reaches to 2.21% with Faradaic efficiency up to 85.7%. Based on the optical and PEC measurements, it is verified that surface plasmon resonance effect of metallic Bi promotes transfer and separation of photogenerated charge and enhances visible-light absorption, thus benefiting higher PEC performance. Especially, Bi shell efficiently hinders the corrosion of BiOI by seawater. Our work provides a novel paradigm of photoanode for efficient and stable PEC seawater splitting. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.