Fabrication and band structure of Ag3PO4-TiO2 heterojunction with enhanced photocatalytic hydrogen evolution

Ag3PO4 was deposited on TiO2 by in-situ precipitation to fabricate Ag3PO4 TiO2 heterojunction with different ratios of Ag3PO4. The electronic band structures of TiO2 and Ag3Pa4 were determined by means of ultraviolet photoelectron spectroscopy and LW visible spectrometry. The Fermi levels of TiO2 and Ag3PO4 were calculated to be -5.09 eV and -5.95 eV, respectively, and accordingly the energy band diagrams were constructed. The hydrogen production rates of bare TiO2 and Ag3PO4 TiO2 heterojunctions were measured under 300 W Xe lamp with a solar filter (AM 1.5). The heterojunction formed with 12 wt% Ag3PO4 showed the highest hydrogen evolution rate (44.5 mu mol g(-1)h(-1)) which is 5.7 times higher than that of TiO2. When Au nanoparticles were deposited on this heterojunction, it resulted in 10.2 times (453.0 mol g(-1)h(-1)) further improvement of hydrogen generation. The hydrogen evolution performance is consistent with the result of photoluminescence analysis. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.