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

Abstract A novel K 2 Nb 2 O 6 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 K 2 Nb 2 O 6 photocatalyst with pyrochlore structure showed higher H 2 production activity than that of perovskite KNbO 3 and commercial Nb 2 O 5 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 µmol/h was reached when 0.7 wt% Pt nanoparticles were used, which was about 20 times higher than that of pristine K 2 Nb 2 O 6 .