A one-pot method to grow pyrochlore H4Nb2O7-octahedron-based photocatalyst

Cubic pyrochlore niobates (A2Nb2O7, Fd-3m) have been shown to exhibit excellent photocatalytic performance and solid niobic acids show great advantages over these niobate photocatalysts. But no pyrochlore niobic acid has been reported. Here we develop a new and one-pot hydrothermal route for high-yield controlled synthesis of pyrochlore H4Nb2O7 with no aid of additives. Combined with the intrinsic loosely pyrochlore structure, the “acidity-promoted effect”, and the high crystallinity, the novel H4Nb2O7 exhibits outstanding photocatalytic activity, i.e., the reaction rate constant of H4Nb2O7 is almost 3 times of that for its amorphous precursor Am–Nb2O5.nH2O, and almost 2 times that of its corresponding calcium pyroniobate. This study discloses insights for the designed strategy of efficient photocatalysts with synergistic features, and this route provides flexibility and selectivity for the deliberate synthesis of other functional materials.