Aerosol-assisted synthesis of crystalline tungsten bronze particles
Provided herein are methods for producing crystalline tungsten bronze oxide particles. The method may include atomizing a liquid solution comprising an alkali metal precursor and a tungsten precursor to produce droplets; mixing the droplets with one or more gaseous flows to produce a combined flow; flowing the combined flow through a heated reactor to provide crystalline tungsten bronze oxide particles having the formula M x WO 3 , wherein M is the alkali metal; and collecting the particles.
1 . A method for producing crystalline tungsten bronze oxide particles, comprising
atomizing a liquid solution comprising an alkali metal precursor and a tungsten precursor to produce droplets, wherein a molar ratio of alkali metal precursor to tungsten precursor is from 0.4:1 to 1:1;
mixing the droplets with one or more gaseous flows to produce a combined flow;
flowing the combined flow through a heated reactor to provide crystalline tungsten bronze oxide particles having the formula M x WO 3 , wherein M is the alkali metal and x is a number from zero to 1; and
collecting the particles.
2 . The method of claim 1 , wherein the particles are collected using baghouse filter sampling, a cyclone, an impactor, a thermo-precipitator, or electrostatic sampling.
3 . The method of claim 1 , wherein the tungsten precursor is ammonium tungstate or tungsten chloride.
4 . The method of claim 1 , wherein the alkali metal is selected from sodium, potassium, and cesium.
5 . The method of claim 1 , wherein the one or more gaseous flows comprise nitrogen and hydrogen.
6 . The method of claim 1 , wherein a flow rate through the reactor is 0.1-15 SLPM.
7 . The method of claim 1 , wherein the reactor comprises a plurality of tube reactors.
8 . The method of claim 1 , wherein the reactor comprises a spiral flow channel.
9 . The method of claim 1 , wherein the reactor is heated to a temperature of 600-1000° C.
10 . A method for producing crystalline tungsten bronze oxide particles, comprising
atomizing a liquid solution comprising an alkali metal precursor and a tungsten precursor to produce droplets;
mixing the droplets with one or more gaseous flows to produce a combined flow;
flowing the combined flow through a heated reactor to provide crystalline tungsten bronze oxide particles having the formula M x WO 3 , wherein M is the alkali metal and x is a number from zero to 1; and
collecting the particles, wherein the particles are in the cubic phase or tetragonal phase.
11 . The method of claim 1 , further comprising recirculating a gaseous flow after the particles are collected.
12 . The method of claim 1 , wherein the liquid solution is an aqueous solution and does not contain an organic solvent.
13 . The method of claim 1 , wherein the method does not include an annealing step.
14 . A method for producing crystalline tungsten bronze oxide particles, comprising
atomizing a liquid solution comprising an alkali metal precursor and a tungsten precursor to produce droplets;
mixing the droplets with one or more gaseous flows to produce a combined flow;
flowing the combined flow through a heated reactor to provide crystalline tungsten bronze oxide particles having the formula M x WO 3 , wherein M is the alkali metal and x is a number from zero to 1;
introducing a dilution flow to the combined flow flowing through the reactor; and
collecting the particles.
15 . The method of claim 14 , wherein a ratio of a flow rate of the dilution flow to a flow rate of the combined flow is from 2:1 to 10:1.
16 . The method of claim 14 , wherein the dilution flow is heated.
17 . The method of claim 14 , wherein the dilution flow is unheated.