Jsm 6700f electron microscope

Scanning electron microscopy (SEM) was carried out using a JEOL-JSM-6700F electron microscope. The samples were coated with gold using a sputter coater and an energy-dispersive X-ray spectrometer (EDX) attachment was employed.
The average oxidation states of vanadium and nickel in the samples were studied by X-ray photoelectron spectroscopy (XPS) using a Thermo ESCALAB 250 spectrometer with monochromatic Al Kα radiation (hν = 1486.6 eV) operating at 150 W with a 500 μm diameter analysis area and a pass energy of 20 eV. The binding energies for sample charging were calibrated using the C 1s peak at 284.8 eV.
N₂ adsorption–desorption measurements were carried out at −196 °C using a Micromeritics Gemini V 2380 autosorption analyzer. The specific surface area was calculated according to the Brunauer–Emmett–Teller (BET) equation and pore distributions were obtained using the Barrett–Joyner–Halenda (BJH) method. Samples were degassed in flowing N₂ at 200 °C for 5 h before measurements.
X-ray diffraction (XRD) patterns were obtained on a Shimadzu XRD-6000 powder diffractometer (Japan) using Cu Kα radiation (λ = 0.1541 nm). The 2θ scan range was 10°–80° with a step size of 0.02°.
The chemical composition of the samples was analyzed using an ARL-9800 X-ray fluorescence spectrometer (XRF) to confirm the EDX results.

The crystalline structure of the catalysts were tested by a Rigaku D/Max-2200 PC X-ray diffractometer using Cu reaction at 40 kV and 40 mA. Micromeritics Tristar 3000 was used to measure the specific surface area and pore structure (pore volume and pore size) of the samples by N₂ adsorption–desorption. The specific surface area and the pore size distribution were calculated using the Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) methods at 77 K. Field emission scanning electron microscopy (SEM) analysis was obtained using JEOL JSM6700F electron microscope. Field emission transmission electron microscopy (TEM) analysis was conducted with a JEOL200CX electron microscope operated at 200 keV. X-ray photoelectron spectroscopy (XPS) signals were collected on a Thermo Scientific ESCALAB 250 instrument. The temperature-programmed reduction with hydrogen (H₂-TPR) were performed on Micromeritics Chemisorb 2750 instrument attached with ChemiSoft TPx software. TPR was carried out from room temperature to 800 °C under 5% H₂ in Ar at a flow rate of 50 mL min⁻¹. The contents of Fe and Pt were measured by using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analyzer on a Vista AX.

X-ray diffraction experiments were done on a MiniFlex II X-ray powder diffractometer (Rigaku, Tokyo, Japan) using Cu Kα radiation (λ=0.15406 nm). The TEM images were recorded on a JEOL JEM-2010 microscope (Tokyo, Japan) at an accelerating voltage of 200 kV. For TEM, the powder samples were ultrasonically dispersed in EtOH, and then deposited and dried on the holey carbon film on a copper grid. The SEM images were recorded on a JEOL JSM-6700F electron microscope. For spectrophotometric measurements, a Lambda 25 UV/Vis spectrophotometer and a NICOLET 380 FT-IR instrument from PerkinElmer were used (Waltham, USA). Water contact angle (CA) measurements were done on a water droplet (drop volume 10 μL) at rt using a Model 250 (p/n 250-F1) goniometer (Ramé-Hart Instrument Co., Succasunna, USA).