Enhanced Near Infrared Reflectance with Brilliant Yellow Hues in Scheelite Type Solid Solutions, (LiLaZn)1/3MoO4–BiVO4 for Energy Saving Products

Brilliant yellow-orange pigments based on the formula Bi1.7RE0.3W0.7Mo0.3O6 (RE = Y, Yb, Gd, Lu) are developed by the traditional solid-state reaction method. Relevant techniques are used for characterization of the crystal structure, morphology feature, reflectance property, and color performance of the prepared pigment. The doping of RE/Mo in Bi2WO6 results in the colors of pigments varying from faint yellow to brilliant yellow-orange. Compared with Bi2WO6 pigment, the typical pigment of Bi1.7Lu0.3W0.7Mo0.3O6 greatly improves the yellow hue component (b*) value to be 72.03. Moreover, the NIR reflectances of all of the samples are higher than 95% , and their NIR solar reflectances are above 94%. The typical pigment of Bi1.7Lu0.3W0.7Mo0.3O6 coated on galvanized sheet exhibits excellent coloring performance with a high NIR solar reflectance (83.32%). The acid/alkali resistance studies reveal that the pigments are chemically stable under the atrocious weather conditions. Thus, the superior performances of synthesized pigments have exhibited potential for energy savings.

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Synthesis and Characterization of Yellow Pigments of Bi_1.7RE_0.3W_0.7Mo_0.3O₆ (RE = Y, Yb, Gd, Lu) with High NIR Reflectance

Huang

Xiao

Zhou

et al. 2018

“…NIR solar reflectance could quantify the solar radiation and evaluate heat accumulation on the surface of materials. The NIR solar reflectance ( R *) of the samples distributed from 700 to 2500 nm were calculated as shown in the following formula where r (λ) is the experimentally measured spectral reflectance (W m –2 ) and i (λ) is the standard solar spectrum (W m –2 nm –1 ) obtained according to the standard of ASTM G173-03 , reference spectra.…”

Section: Methodsmentioning

confidence: 99%

Thermal Insulation Performance of Novel Coated Fabrics Based on Fe-Doped BaSnO₃ Near-Infrared Reflectance Pigments

Wang

Han

et al. 2021

In this paper, a series of coated fabrics based on Fe-doped BaSnO3 (BaSn1–x Fe x O3−δ, x = 0.00, 0.05, 0.10, 0.20, 0.25) powder pigments were prepared. The results indicate that the developed pigments are substitutional solid solutions with no impurity and the valencies of iron confirmed by X-ray photoelectron spectroscopy (XPS) are +2 and +3. The BaSn1–x Fe x O3−δ pigments possess high near-infrared (NIR) solar reflectance (64.92–79.81%), and the change in the near-infrared reflectance value can be explained by the free carrier concentration and electron trap theory. The pigments exhibit the alteration of yellow-green to brown, which is ascribed to the charge-transfer transition (Sn 5s + 5p ↔ Fe 3d). The BaSn1–x Fe x O3−δ-coated fabrics exhibit excellent high NIR solar reflectance and thermal insulating performance. The NIR solar reflectance of the BaSn0.80Fe0.20O3−δ-coated fabric is up to 64.30%. Compared with those of brown uncoated fabric and conventional brown (Pigment Yellow 42) coated fabric, the inner surface temperature of the BaSn0.80Fe0.20O3−δ-coated fabric is lowered by 7.6 and 4.2 °C, while the heat absorption is reduced by 51.0 and 37.9%, respectively. The coated fabric shows excellent washing durability and chemical stability. In summary, these coated fabrics have the potential to serve as thermal insulation coated fabrics.

“…In recent years, alkali rare earth bismolybdates of the type ARE(MO 4 ) 2 with stable physical and chemical properties and high thermal stability have received extensive attention in the fields of electricity, light, catalysis, and magnetism. − Rao et al synthesized a series of bright yellow pigments (LiLa) 1/2 MoO 4 –BiVO 4 and (LiLaZn) 1/3 MoO 4 –BiVO 4 by introducing alkali rare earth bimolybdates. , Table displays the previously reported studies on the improvement of optical properties based on bismuth vanadate. In tetragonal scheelite with a general formula of ABO 4 , various cations on the A site can be substituted to adjust the performance.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Yellow Pigments (Li_0.4RE_0.6Al_0.6)_1/2MoO₄–BiVO₄ with High NIR Reflectance

Feng

Xiao

et al. 2021

In this work, a new type of near-infrared (NIR) reflective yellow pigment with a general formula of [(Li 0.4 RE 0.6 Al 0.6 ) x/2 Bi 1−x ][Mo x V 1−x ]O 4 was prepared by a solid-phase reaction calcined at a high temperature of 700 °C. Xray diffraction (XRD), scanning electron microscope (SEM), a UV−vis−NIR spectrophotometer, and other methods were used to characterize the structure, morphology, and optical properties of synthetic pigments. For a series ofO 4 pigments, when x > 0.2, bismuth vanadate changes from the monoclinic phase (space group I2/b(15)) to the tetragonal scheelite phase (space group I4 1 /a(88)). The structures of the pigments are all tetragonal scheelite phases, and the difference in their color rendering is mainly due to the differences between the valence band and the conduction band and the difference in the band gap caused by different rare earth elements. The NIR reflectance (R %) and NIR solar reflectance (R* %) of [(Li 0.4 La 0.6 Al 0.6 ) 0.1 Bi 0.8 ][Mo 0.2 V 0.8 ]O 4 pigments are 96.64 and 93.10% (b* = 77.13, C* = 77.6), respectively. In the acid and alkali resistance test, the color difference values ΔE* of the pigment before and after soaking are less than 5. Finally, the thermal infrared test of the synthetic pigments and commercial pigments on galvanized plates without or with TiO 2 was performed. The experimental results show that the temperature difference between the synthetic pigment and commercial bismuth yellow can reach 11 °C. Therefore, it is believed that the synthetic pigment can reflect more heat radiation from sunlight and has better heat insulation performance. The synthetic pigment has higher reflectivity than the commercially available bismuth vanadate pigment, showing its application potential.