Synergetic effect of copper species as cocatalyst on LaFeO3 for enhanced visible-light photocatalytic hydrogen evolution

摘要

LaFeO3 has been reported to have excellent optoelectronic properties and a narrow bandgap, which make it a promising candidate for photocatalytic reactions. In this work, to further improve the photocatalytic water-splitting performance by enhancing the separation of photo-excited carriers and providing active sites for H-2 production, cocatalysts (copper species) supported on the perovskite-type oxide LaFeO3 was obtained by a citrate complexation and reduction treatment. Copper ions in the perovskite lattice are easily reduced and LaFeO3 possesses good stability in reducing atmospheres; thus, a series of stable LaFeO3 with a controllable copper species were synthesized and characterized by XRD, DRS, XPS and PL. The results showed that copper species (Cu-0 and Cu+) supported on the LaFeO3 surface brought about a significant enhancement of photocatalytic activity. The LaFe0.8 + LaCu0.2 treated at 300 degrees C exhibited the highest photocatalytic activity, with a H-2 evolution rate of 343 mu mol g(-1) h(-1), which was attributed to the fact that a proper Cu-0 to Cu+ ratio (Cu-0/Cu+ = 1.34) could serve as a cocatalyst for photocatalytic hydrogen evolution, providing accelerated electron hole separation and proton-reduction sites. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.