Z-scheme electronic transfer of quantum-sized α-Fe2O3 modified g-C3N4 hybrids for enhanced photocatalytic hydrogen production

A quantum-sized hematite iron oxide (alpha-Fe2O3)/graphitic carbon nitride (g-C3N4) hybrids have been designed and constructed through a facile in situ calcination treatment. The alpha-Fe2O3/g-C3N4 hybrids were analyzed via various characterization techniques including XRD, TEM, UV-Vis DRS, XPS, and their photocatalytic efficiencies were evaluated by visible light-driven hydrogen evolution. The results reveal that the cooperation of alpha-Fe2O3 and g-C3N4 during fabrication process leads to synergy effects of not only the morphology but also the microstructure. These hybrids exhibit much higher hydrogen evolution efficiency than pure g-C3N4 under visible-light illumination due to their improved light harvesting capability, enhancement of surface areas, predominant (110) facet exposure of alpha-Fe2O3 as well as a prominent quantum size effect, and highly efficient electron transfer and separation. A proposed Z-scheme mechanism was further verified experimentally. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.