Tga dsc1 1600

SEM and TEM images of the samples were taken using a Sigma 300 FE-SEM (Zeiss, Germany) and a JEM-2100F TEM (Jeol, Japan) microscopes respectively. FTIR spectra for the samples ranged from 500 to 4000 cm⁻¹ using NICOLET 380 spectrophotometer (Thermo Nicolet Corp., American) with 32 successive scans at a resolution of 4 cm⁻¹. XRD patterns were conducted using a D/MAX 2500 PC diffractometer (Rigaku, Japan) equipped with Cu Kα radiation, the generator power settings being 40 kV and 50 mA from 5° to 40° (2θ) at a scan rate of 0.01°/min. The surface area and porosity of the samples were determined from N₂ adsorption-desorption experiments using a surface area and pore size analyzer (Nova 2200e, Quantachrome, USA). Thermal properties of the samples were measured by a thermogravimetric analyzer (TGA/DSC1/1600, Mettler-Toledo, Switzerland), with a temperature range of 30–800 ^oC, at a heating rate of 20 ^oC/min under the airflow. XPS spectra were recorded on a Thermo Scientific K-alpha X-ray photo-electron spectrometer equipped with an Al Kα X-ray source (1486.6 eV).

The morphologies Co-MOF
and M-Co₃O₄ were characterized by scanning electron
microscopy (SEM, JEOL JSM-7800F, Kabushiki Kaisha), and the operating
voltage of the X-ray tube was 15 kV. A high-resolution transmission
electron microscope (HRTEM, Talos F200S, Thermofisher Scientific)
operated at 200 kV was used to examine the micrographs of M-Co₃O₄. HRTEM, energy-dispersive X-ray spectroscopy
(EDS), and high-angle annular dark field scanning transition electron
microscopy (HAADF-STEM) measurements performed at 200 kV were combined
to characterize the crystal structure and elemental distribution of
M-Co₃O₄. X-ray diffraction (XRD, D8 Advance,
Bruker) was used to study the constitution of the synthesized materials,
and Cu Kα (λ = 0.154) was utilized as a source of radiation.
The specific surface area, pore volume, and pore size distribution
of M-Co₃O₄ were determined by the Brunauer–Emmett–Teller
(BET) method and the Barrett–Joyner–Halenda (BJH) method
combined with nitrogen adsorption–desorption isotherms measured
by Quadrasorb 2MP. The thermal transformation properties of Co-MOF
were examined using a thermogravimetric analyzer (TGA, TGA/DSC 1/1600,
Mettler Toledo). X-ray photoelectron spectroscopy (XPS, Escalab 250Xi,
Thermofisher Scientific) measurements were used to investigate the
surface valence states of the catalyst M-Co₃O₄ before and after the reaction.