This invention describes a new method for reducing the bandgap of titanium dioxide by forming solid solutions with other dioxides that a) have either rutile or anatase crystal structure, b) exhibit either metallic or semiconducting characteristics and c) maintain stable 4+ valence during high temperature processing as well as during cooling to room temperature.

According to one embodiment, nano metal compound particles are provided. The nano metal compound particles have an average particle size of 50 nm or less. The nano metal compound particles have a peak .sub.t of 2.8 eV or less. The peak .sub.t corresponds to a resonant frequency of an oscillator according to a spectroscopic ellipsometry method fitted to a Lorentz model.

According to one embodiment, nano metal compound particles are provided. The nano metal compound particles have an average particle size of 50 nm or less. The nano metal compound particles have a peak .sub.t of 2.8 eV or less. The peak .sub.t corresponds to a resonant frequency of an oscillator according to a spectroscopic ellipsometry method fitted to a Lorentz model.

Provided is a method for preparing metal/molybdenum oxide nanoparticles, the method including: preparing polycrystalline molybdenum oxide particles; and obtaining metal-doped molybdenum oxide nanoparticles by dissolving the polycrystalline molybdenum oxide particles and a metal precursor in a first solvent, and then performing a solvothermal reaction.

Provided is a method for preparing metal/molybdenum oxide nanoparticles, the method including: preparing polycrystalline molybdenum oxide particles; and obtaining metal-doped molybdenum oxide nanoparticles by dissolving the polycrystalline molybdenum oxide particles and a metal precursor in a first solvent, and then performing a solvothermal reaction.

A doped sodium vanadium phosphate and a preparation method and application thereof. Preparation steps of a nitrogen-doped peony-shaped molybdenum oxide in raw materials of the doped sodium vanadium phosphate are as follows: adding a regulator into a molybdenum-containing solution for reaction, concentrating and thermal treatment to obtain a peony-shaped molybdenum oxide; and dissolving the peony-shaped molybdenum oxide in a conditioning agent, and adding an amine source for standing, centrifuging, washing and heat treatment, thus obtaining the nitrogen-doped peony-shaped molybdenum oxide.

A doped sodium vanadium phosphate and a preparation method and application thereof. Preparation steps of a nitrogen-doped peony-shaped molybdenum oxide in raw materials of the doped sodium vanadium phosphate are as follows: adding a regulator into a molybdenum-containing solution for reaction, concentrating and thermal treatment to obtain a peony-shaped molybdenum oxide; and dissolving the peony-shaped molybdenum oxide in a conditioning agent, and adding an amine source for standing, centrifuging, washing and heat treatment, thus obtaining the nitrogen-doped peony-shaped molybdenum oxide.

A doped sodium vanadium phosphate and a preparation method and application thereof. Preparation steps of a nitrogen-doped peony-shaped molybdenum oxide in raw materials of the doped sodium vanadium phosphate are as follows: adding a regulator into a molybdenum-containing solution for reaction, concentrating and thermal treatment to obtain a peony-shaped molybdenum oxide; and dissolving the peony-shaped molybdenum oxide in a conditioning agent, and adding an amine source for standing, centrifuging, washing and heat treatment, thus obtaining the nitrogen-doped peony-shaped molybdenum oxide.

A doped sodium vanadium phosphate and a preparation method and application thereof. Preparation steps of a nitrogen-doped peony-shaped molybdenum oxide in raw materials of the doped sodium vanadium phosphate are as follows: adding a regulator into a molybdenum-containing solution for reaction, concentrating and thermal treatment to obtain a peony-shaped molybdenum oxide; and dissolving the peony-shaped molybdenum oxide in a conditioning agent, and adding an amine source for standing, centrifuging, washing and heat treatment, thus obtaining the nitrogen-doped peony-shaped molybdenum oxide.

Niobium oxide particles which have a controlled crystal shape and exhibit excellent characteristics are provided. The niobium oxide particles include molybdenum. The niobium oxide particles preferably have a polyhedral, columnar or acicular shape. The MoO.sub.3 content (M.sub.1) measured by XRF analysis of the niobium oxide particles is preferably 0.1 to 40 mass % relative to the niobium oxide particles taken as 100 mass %. A method for producing the niobium oxide particles described above includes calcining a niobium compound in the presence of a molybdenum compound.