An efficient tandem photoelectrochemical cell composed of FeOOH/TiO_2/BiVO_4 and Cu_2O for self-driven solar water splitting

摘要

An integrated solar water splitting tandem cell without external bias was designed using a FeOOH modified TiO2/BiVO4 photoanode as a photoanode and p-Cu2O as a photo-cathode in this study. An apparent photocurrent (0.37 mA/cm(2) at operating voltage of +0.36 V-RHE) for the tandem cell without applied bias was measured, which is corresponding to a photoconversion efficiency of 0.46%. Besides, the photocurrent of FeOOH modified TiO2/BiVO4 Cu2O is much higher than the operating point given by pure BiVO4 and Cu2O photocathode (-0.07 mA/cm(2) at +0.42 VRHE). Then we established a FeOOH modified TiO2/BiVO4 Cu2O two-electrode system and measured the current density voltage curves under AM 1.5G illumination. The unassisted photocurrent density is 0.12 mA/cm(2) and the corresponding amounts of hydrogen and oxygen evolved by the tandem PEC cell without bias are 2.36 umol/cm(2) and 1.09 urnol/cm(2) after testing for 2.5 h. The photoelectrochemical (PEC) properties of the FeOOH modified TiO2/BiVO4 photoanode were further studied to demonstrate the electrons transport process of solar water splitting. This aspect provides a fundamental challenge to establish an unbiased and stabilized photoelectrochemical (PEC) solar water splitting tandem cell with higher solar to -hydrogen efficiency. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.