Preparation method and application of tungsten-niobium composite oxide

The invention discloses a preparation method and application of a tungsten-niobium composite oxide WNb6O18. The tungsten-niobium composite oxide has a Wadsley-Roth shear structure formed by a 3*4 NbO6 octahedral structure unit. The preparation method is a high-temperature solid-phase method, and comprises: providing a tungsten source by tungsten/tungsten dioxide/tungsten trioxide, providing a niobium source by niobium/niobium dioxide/niobium pentoxide, weighing the tungsten source and niobium source raw materials according to a molar ratio of tungsten to niobium being 1: 6, carrying out ball milling, uniformly mixing, carrying out tabletting forming, pre-sintering at 700-800 DEG C for 6 hours, taking out, uniformly ball-milling, drying, carrying out tabletting forming again, and sintering at a high temperature of 1100-1200 DEG C in a muffle furnace for 3-6 hours to obtain the niobium-based composite oxide WNb6O18. The preparation method is simple to operate, the phase purity of the obtained composite oxide is