Na2SO4-assisted synthesis of hexagonal-phase WO3nanosheet assemblies with applicable electrochromic and adsorption properties

For the first time, a mesoporous hexagonal-phase Na0.17WO3.085·0.29H2O nanosheet/microflower hierarchical structure has been synthesized employing a one-pot hydrothermal process with the assistance of Na2SO4. It is shown that Na2SO4 not only acts as a stabilizer to facilitate the generation of a metastable hexagonal phase, but also function as a structure directing agent to assist the construction of nanosheet assemblies. The formation mechanisms have been rationalized. The materials have been thoroughly characterized by XRD/BET/FESEM/EDX/TEM/TGA. This hexagonal-phase Na0.17WO3.085·0.29H2O nanosheet/microflower hierarchical structure exhibits applicable electrochromic and adsorptive properties due to its unique crystallographic configuration and microstructures, promising its application in energy-saving smart windows and wastewater treatment.