INFRARED SELECTIVE RADIATION COOLING NANO-FUNCTIONAL COMPOSITION AND PREPARATION METHOD THEREOF

Abstract

An infrared selective radiation cooling nano-functional composition and a preparation method thereof, wherein the composition is prepared from silica, a rare earth silicate compound and a molybdate compound according to a mass ratio of 1:(0.5-2):(0.5-2) by ball milling and uniform mixing, and the silica, the rare earth silicate compound and the molybdate compound have high infrared selective radiation performance at 8-10 μm, 9-12 μm and 10-14 μm. The rare earth silicate and molybdate compound are prepared by a sol-gel and a high-temperature solid phase process according to stoichiometric ratios SiO.sub.2-(0.5-2)Re.sub.2O.sub.3-(0.1-1.0)Na.sub.2O (Re═La, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, Y or Sc) and RMoO.sub.4 (R═Mg, Ca, Sr or Ba). The infrared selective radiation cooling nano-functional composition prepares functional devices such as day and night double-effect radiation coolers to provide zero-energy cooling, energy saving and efficiency improvement functions for buildings, grain and oil stores, solar battery back plates and the like.

Claims

1. An infrared selective radiation cooling nano-functional composition, prepared from nano-silica, a rare earth silicate compound and a molybdate compound according to a mass ratio of 1:(0.5-2):(0.5-2) by ball milling and uniform mixing, wherein the rare earth silicate compound meets a stoichiometric ratio SiO.sub.2-(0.5-2)Re.sub.2O.sub.3-(0.1-1.0)Na.sub.2O and has high infrared selective radiation performance at 9-12 μm, and Re is La, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, Y or Sc; the molybdate compound meets a stoichiometric ratio RMoO.sub.4 and has high infrared selective radiation performance at 10-14 μm, and R is Mg, Ca, Sr or Ba.

2. The infrared selective radiation cooling nano-functional composition according to claim 1, wherein the nano-functional composition has high selective absorption-radiation performance in an atmospheric window of 8-14 μm and is transparent to ultraviolet-visible-near infrared sunlight.

3. A preparation method of the infrared selective radiation cooling nano-functional composition according to claim 1, specifically comprising the following steps: (a) accurately weighing nano-silica, rare earth nitrate and sodium nitrate according to a stoichiometric ratio of a rare earth silicate compound, mixing and dispersing into an ethanol-water mixed solution; evaporating a solvent in a water bath under stirring to obtain a gel; presintering the gel at a low temperature of 120-150° C. for 3-6 hours, and then thermally heating at 600-900° C. for 3-12 hours to obtain a rare earth silicate compound; (b) accurately weighing ammonium molybdate and alkaline earth metal nitrate according to a stoichiometric ratio of a molybdate compound and dissolving in deionized water; preparing a citric acid solution and adding dropwise into the solution above, adjusting the pH to 3.0-4.0, and evaporating a solvent in a water bath under stirring to obtain a gel; presintering the gel at a low temperature of 120-150° C. for 3-6 hours, and then thermally heating at 800-1000° C. for 3-12 hours to obtain a molybdate compound; (c) weighing a certain amount of nano-silica, the rare earth silicate compound and the molybdate compound according to a mass ratio of a nano-functional composition, and processing by using a high-speed grinding and dispersing machine to obtain an infrared selective radiation cooling nano-functional composition.

4. The method according to claim 3, wherein a temperature of the water bath in step (a) is 70-80° C.

5. The method according to claim 3, wherein a mass concentration of the citric acid solution in step (b) is 5%-10%; the pH is adjusted with ammonia water; a temperature of the water bath is 70-80° C.

6. The method according to claim 3, wherein a rotation speed of the high-speed grinding and dispersing machine in step (c) is 300-400 r/min, and the processing time is 2-6 hours.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is an infrared selective absorption/radiation spectrum of Embodiment 1.

DETAILED DESCRIPTION

[0017] In order to better understand the present invention, the following embodiments are specifically given to illustrate the present invention in detail, but not used to limit the content of the present invention. With deepening of description, the advantages and features of the present invention become clearer, but are not used as a basis for limiting the present invention. After reading the present invention, those skilled in the art should understand that modifications or replacements of the present invention in various equivalent forms still fall within the protection scope of the present invention.

Embodiment 1

[0018] The embodiment discloses an infrared selective radiation cooling nano-functional composition and a preparation process thereof, and the preparation process includes the following steps:

[0019] (a) 30 g of nano-silica (50 nm, commercially available), 324.9 g of lanthanum nitrate and 85 g of sodium nitrate are accurately weighed according to a stoichiometric ratio SiO.sub.2—La.sub.2O.sub.3-0.5Na.sub.2O of a rare earth lanthanum silicate compound and dissolved in an ethanol-water mixed solution, a solvent is evaporated in a water bath under stirring at 70° C. to obtain a gel, and the gel is thermally treated at 120° C. for 6 hours to obtain rare earth lanthanum silicate presintered powder which is then thermally treated at 700° C. for 12 hours to obtain a rare earth lanthanum silicate compound with an average particle size of 106 nm.

[0020] (b) 82 g of calcium nitrate and 170 g of ammonium dimolybdate are accurately weighed according to a chemical formula CaMoO.sub.4 of calcium molybdate and dissolved in deionized water. An 8% citric acid solution is prepared, added dropwise into the solution above and stirred vigorously, the pH is adjusted to 3.5 with ammonia water, a solvent is evaporated in a water bath under stirring at 70° C. to obtain a gel, and the gel is thermally treated at 150° C. for 6 hours to obtain calcium molybdate presintered powder which is then thermally treated at 900° C. for 6 hours to obtain calcium molybdate with an average particle size of 103 nm.

[0021] (c) 40 g of nano-silica (50 nm, commercially available), 40 g of the rare earth lanthanum silicate compound in step (a) and 40 g of the calcium molybdate in step (b) are separately weighed according to a weight ratio 1:1:1 of a functional powder composition and added into a ball milling tank of a high-speed grinding and dispersing machine for ball milling at a rotation speed of 300 r/min for 6 hours to obtain a required infrared selective radiation cooling nano-functional composition, and the highest absorption/emissivity of the nano-functional composition in an infrared wavelength range of 8-14 μm is 0.90. An infrared selective absorption/radiation spectrum of the nano-functional composition is as shown in FIG. 1.

Embodiment 2

[0022] The embodiment discloses an infrared selective radiation cooling nano-functional composition and a preparation process thereof, and the preparation process includes the following steps:

[0023] (a) 24 g of nano-silica (50 nm, commercially available), 134.5 g of samarium nitrate and 42.5 g of sodium nitrate are accurately weighed according to a stoichiometric ratio SiO.sub.2-1.5Sm.sub.2O.sub.3-0.25Na.sub.2O of a rare earth lanthanum silicate compound and dissolved in an ethanol-water mixed solution, a solvent is evaporated in a water bath under stirring at 70° C. to obtain a gel, and the gel is thermally treated at 150° C. for 3 hours to obtain rare earth lanthanum silicate presintered powder which is then thermally treated at 900° C. for 3 hours to obtain a rare earth lanthanum silicate compound with an average particle size of 115 nm.

[0024] (b) 72.2 g of magnesium nitrate and 85 g of ammonium dimolybdate are accurately weighed according to a chemical formula MgMoO.sub.4 of calcium molybdate and dissolved in deionized water. A 10% citric acid solution is prepared, added dropwise into the solution above and stirred vigorously, the pH is adjusted to 3.0 with ammonia water, a solvent is evaporated in a water bath under stirring at 80° C. to obtain a gel, and the gel is thermally treated at 120° C. for 6 hours to obtain calcium molybdate presintered powder which is then thermally treated at 1000° C. for 3 hours to obtain calcium molybdate with an average particle size of 103 nm.

[0025] (c) 40 g of nano-silica (50 nm, commercially available), 60 g of the rare earth lanthanum silicate compound in step (a) and 15 g of the calcium molybdate in step (b) are separately weighed according to a weight ratio 1:1.5:0.5 of a functional powder composition and added into a ball milling tank of a high-speed grinding and dispersing machine for ball milling at a rotation speed of 350 r/min for 4 hours to obtain a required infrared selective radiation cooling nano-functional composition, and the highest absorption/emissivity of the nano-functional composition in an infrared wavelength range of 8-14 μm is 0.89.

Embodiment 3

[0026] The embodiment discloses an infrared selective radiation cooling nano-functional composition and a preparation process thereof, and the preparation process includes the following steps:

[0027] (a) 30 g of nano-silica (30 nm, commercially available), 487.4 g of lanthanum nitrate and 42.5 g of sodium nitrate are accurately weighed according to a stoichiometric ratio SiO.sub.2-1.5La.sub.2O.sub.3-0.5Na.sub.2O of a rare earth lanthanum silicate compound and dissolved in an ethanol-water mixed solution, a solvent is evaporated in a water bath under stirring at 80° C. to obtain a gel, and the gel is thermally treated at 120° C. for 6 hours to obtain rare earth lanthanum silicate presintered powder which is then thermally treated at 650° C. for 12 hours to obtain a rare earth lanthanum silicate compound with an average particle size of 94 nm.

[0028] (b) 82 g of calcium nitrate and 170 g of ammonium dimolybdate are accurately weighed according to a chemical formula CaMoO.sub.4 of calcium molybdate and dissolved in deionized water. An 8% citric acid solution is prepared, added dropwise into the solution above and stirred vigorously, the pH is adjusted to 4.0 with ammonia water, a solvent is evaporated in a water bath under stirring at 70° C. to obtain a gel, and the gel is thermally treated at 150° C. for 3 hours to obtain calcium molybdate presintered powder which is then thermally treated at 900° C. for 3 hours to obtain calcium molybdate with an average particle size of 90 nm.

[0029] (c) 35 g of nano-silica (50 nm, commercially available), 17.5 g of the rare earth lanthanum silicate compound in step (a) and 70 g of the calcium molybdate in step (b) are separately weighed according to a weight ratio 1:0.5:2 of a functional powder composition and added into a ball milling tank of a high-speed grinding and dispersing machine for ball milling at a rotation speed of 300 r/min for 6 hours to obtain a required infrared selective radiation cooling nano-functional composition, and the highest absorption/emissivity of the nano-functional composition in an infrared wavelength range of 8-14 μm is 0.91.

Embodiment 4

[0030] The embodiment discloses a preparation method of a high-selectivity photon radiation cooler, and the preparation method includes the following steps:

[0031] (a) 30 g of nano-silica, 162.5 g of lanthanum nitrate, 34.3 g of gadolinium nitrate and 85 g of sodium nitrate are accurately weighed according to a stoichiometric ratio SiO.sub.2-0.5La.sub.2O.sub.3-0.1Gd.sub.2O.sub.3-1.0Na.sub.2O of rare earth dysprosium silicate and dissolved in a certain volume of an ethanol-water mixed solution, a solvent is evaporated in a water bath under stirring at 70° C. to obtain a gel, and the gel is thermally treated at 150° C. for 3 hours to obtain rare earth dysprosium silicate presintered powder which is then thermally treated at 750° C. for 10 hours to obtain a rare earth dysprosium gadolinium silicate compound with an average particle size of 120 nm.

[0032] (b) 41 g of calcium nitrate and 85 g of ammonium dimolybdate are accurately weighed according to a chemical formula CaMoO.sub.4 of calcium molybdate and dissolved in deionized water. A 5% citric acid solution is prepared, added dropwise into the solution above and stirred vigorously, the pH is adjusted to 4.0 with ammonia water, a solvent is evaporated in a water bath under stirring at 80° C. to obtain a gel, and the gel is thermally treated at 150° C. for 4 hours to obtain calcium molybdate presintered powder which is then thermally treated at 850° C. for 12 hours to obtain calcium molybdate with an average particle size of 85 nm.

[0033] (c) 28 g of nano-silica (50 nm, commercially available), 56 g of the rare earth dysprosium gadolinium silicate compound in step (a) and 42 g of the calcium molybdate in step (b) are separately weighed according to a weight ratio 1:2:1.5 of a functional powder composition and added into a ball milling tank of a high-speed grinding and dispersing machine for ball milling at a rotation speed of 300 r/min for 6 hours to obtain a required infrared selective radiation cooling nano-functional composition, and the highest absorption/emissivity of the nano-functional composition in an infrared wavelength range of 8-14 μm is 0.92.