Asap 2020 v3.00h

X-ray powder diffraction (XRD) was performed using a Shimadzu XRD-6000 diffractometer with a CuKα₁ irradiation over a 2θ range from 10 to 90° to analyze the crystal phases of the samples. The morphologies of the as-obtained products were characterized and analyzed by transmission electron microscope (TEM). High-resolution TEM (HR-TEM) images were obtained using a JEOL JEM-2100 microscopy, operated at an acceleration voltage of 200 kV, to characterize the sizes and crystal structures of WO₃ and Pd-WO₃ nanosheets. The surface areas were measured on a surface area analyzer (Micromeritics ASAP 2020 V3.00H) and calculated using the Brunauer–Emmett–Teller (BET) equation. X-ray photoelectron spectroscopy (XPS, K-alpha) was used to investigate electron configurations of the surfaces of WO₃ and Pd-WO₃ nanosheets.

FT-IR spectra were recorded on Bruker Tensor 27 IR spectrometer using the KBr pellet method. XPS measurements were carried out on an ESCAL Lab 220i-XL specrometer under a pressure of ∼3 × 10⁻⁹ mbar (1 mbar = 100 Pa). XRD measurements were performed on an X-ray diffractometer (D/MAX-RC, Japan) at 40 kV and 200 mA with Cu Kα (λ = 0.154 nm) radiation. TEM images were achieved on a TEM JeoL-1011 with an accelerating voltage of 120 kV. SEM images were obtained on a Hitachi S-4800 Scanning Electron Microscope operated at 15 kV. Elemental mappings of Zr-Phy-DES were recorded using a JEOL-2100F high resolution of transmission electron microscopy (HR-TEM). The content of Zr was detected by ICP-AES (VISTA-MPX). N₂ adsorption-desorption isotherms were obtained on the Micromeritics ASAP 2020 V3.00H (USA) surface area analyzer at 77 K at high vacuum. Temperature-programmed desorption of ammonia (NH₃-TPD) and temperature-programmed desorption of carbon dioxide (CO₂-TPD) were conducted on Micromeritics’ AutoChem 2950 HP Chemisorption Analyzer.