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

• A controllable copper species (Cu0 and Cu+) supported on LaFeO3 was synthesized.
• Hydrogen-treatment was used to control copper species and content on the surface.
• Photocatalyst with optimized copper showed hydrogen evolution of 343 μmol h−1 g−1.
• The high activity was attributed to better charge separation on the surface.

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 H2 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 (Cu0 and Cu+) supported on the LaFeO3 surface brought about a significant enhancement of photocatalytic activity. The LaFe0.8 + LaCu0.2 treated at 300 °C exhibited the highest photocatalytic activity, with a H2 evolution rate of 343 μmol g−1 h−1, which was attributed to the fact that a proper Cu0 to Cu+ ratio (Cu0/Cu+ = 1.34) could serve as a cocatalyst for photocatalytic hydrogen evolution, providing accelerated electron–hole separation and proton-reduction sites.

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