K2Nb2O7

K2Nb2O7, or potassium niobate, is a layered oxide compound that belongs to the family of niobates with the formula K2Nb2O7. Its structure consists of NbO6 octahedra arranged into layered, perovskite-like blocks, with potassium ions occupying interlayer spaces. This layering gives K2Nb2O7 a two-dimensional character and contributes to its wide band gap and distinctive photo-physical properties.

Synthesis of K2Nb2O7 is commonly achieved by solid-state reaction of Nb2O5 with a potassium source such as K2CO3 at high temperatures (typically in the 850–1000 °C range), often with repeated grinding and calcination to promote phase formation. Alternative methods include hydrothermal or solvothermal routes that yield nanosheets and nanorods, enabling control over morphology and particle size.

Physically, K2Nb2O7 is a white or light-colored powder with a wide band gap in the ultraviolet range, typically around 3.3 eV, making it a wide-band-gap semiconductor. It is stable in air and can be thermally robust. Exfoliation or chemical treatment can produce single- to few-layer niobate nanosheets, which often exhibit higher surface area and altered electronic properties. Doping or coupling with co-catalysts can modulate its optical response and catalytic activity.

Applications of K2Nb2O7 primarily center on photocatalysis. It has been explored for UV-driven water splitting and for degradation of organic pollutants, with performance enhanced by nanostructuring, doping, or sensitization with dyes or metal co-catalysts. It is also studied as a support material in composite photocatalysts and related solid-state devices.

See also: potassium niobate, KNbO3, and other niobates such as K4Nb6O17 and K2Nb8O23.