One-Pot Hydrothermal Synthesis and Photocatalytic Hydrogen Evolution of Pyrochlore Type K2Nb2O6

A novel K2Nb2O6 photocatalyst with pyrochlore structure has been synthesized via a facile one-pot hydrothermal route with no aid of additives. The as-prepared samples were characterized by powder X-ray diffraction, ultraviolet-visible spectroscopy and field emission scanning electron microscopy. The photocatalytic H-2 evolution was performed in an aqueous methanol solution under UV light irradiation. The as-prepared K2Nb2O6 photocatalyst with pyrochlore structure showed higher H-2 production activity than that of perovskite KNbO3 and commercial Nb2O5 powders in the absence of cocatalysts, due mainly to its unique crystal and energy band structures. The rate of H-2 evolution can be significantly enhanced by loading of Pt nanoparticles. The highest H-2 evolution rate of 121 mu mol/h was reached when 0.7 wt% Pt nanoparticles were used, which was about 20 times higher than that of pristine K2Nb2O6.