RESUMO
Electrochromic smart windows have attracted great attention due to their dynamic regulation of the solar spectrum. NiO and MnO2 are typical anodic coloration materials and widely investigated as complementary electrodes with WO3. However, NiO and MnO2 films often cannot be bleached to complete transparency, resulting in low transmittances and low optical modulations in the short-wavelength visible region. Herein, we report a porous nickel manganese layered double hydroxide (NiMn-LDH) nanosheet film directly grown on fluorine-doped tin oxide (FTO) glass using a one-step hydrothermal method, which demonstrates a high transmittance of 80.1% at 550 nm (without deduction of FTO glass). Induced by the double-redox couples of Ni2+/Ni3+ and Mn3+/Mn4+ associated synergistic electrochromic effect, the as-grown NiMn-LDH film electrode exhibits a large optical modulation of 68.5% at 550 nm, and a large solar irradiation modulation of 59.0% in the visible region of 400-800 nm. After annealing at 450 °C for 2 h, the NiMn-LDH film can be transformed into Ni6MnO8 film with a reduced optical modulation of 30.0% at 550 nm. Furthermore, the NiMn-LDH film electrode delivers an areal capacitance of 30.8 mF cm-2 at a current density of 0.1 mA cm-2. These results suggest that the as-prepared NiMn-LDH film electrode is a promising candidate for both electrochromic and energy storage applications.
RESUMO
Inorganic materials have been extensively studied for visible electrochromism in the past few decades. However, the single inorganic electrochromic (EC) material commonly exhibits a single color change, leading to a narrow spectrum of modulation, which offsets or limits the maximally energy-saving ability. Here, we present a wide-spectrum modulated EC device designed by combining the complementary EC nanocomposite of manganese dioxide (MnO2) and Prussian blue (PB) for enhanced energy savings. Porous MnO2 nanostructures serve as host frameworks for the templated growth of PB, resulting in MnO2/PB nanocomposites. The complementary optical modulation ranges of MnO2 and PB enable a widen-spectrum modulation across the solar region with the development of the MnO2/PB nanocomposite. The colored MnO2/PB device exhibited an optical modulation of 32.1% in the wide solar spectrum range of 320-1100 nm and blocked 72.0% of the solar irradiance. Furthermore, fast switching responses (2.7 s for coloration and 2.1 s for bleaching) and a high coloration efficiency (83.1 cm2·C-1) of the MnO2/PB EC device are also achieved. The high EC performance of the MnO2/PB nanocomposite device provides a new strategy for the design of high-performance energy-saving EC smart windows.
RESUMO
Wheat (Triticum aestivum L.) is a widely cultivated crop and one of the most commonly consumed food grains in the world. It possesses several nutritional elements. Increasing attention to wheat grain phenolics bioactivity is due to the increasing demand for foods with natural antioxidants. To provide a comprehensive understanding of phenolics in wheat grain, this review first summarizes the phenolics' form and distribution and the phenolic components identified in wheat grain. In particular, the biosynthesis path for phenolics is discussed, identifying some candidate genes involved in the biosynthesis of phenolic acids and flavonoids. After discussing the methods for determining antioxidant activity, the effect of genotypes, environmental conditions, and cultivation systems on grain phenolic component content are explored. Finally, the bioavailability of phenolics under different food processing method are reported and discussed. Future research is recommended to increase wheat grain phenolic content by genetic engineering, and to improve its bioavailability through proper food processing. © 2021 Society of Chemical Industry.