**2.2 Characterization of ZSM-5 zeolites**

X-ray powder diffraction patterns were obtained with a PANalytical X-Pert Pro powder diffractometer in 5–60° 2θ with Cu Kα radiation and scanning step of 0.013° s<sup>−</sup><sup>1</sup> . Scanning electron microscope images were undertaken on a FE-SEM FEI INSPECT F50 instrument. Si, Al, and Co content was determined by using atomic absorption spectroscopy technique with the use of Shimadzu AA600 instrument. Infrared spectra were collected from pressed disks of sample mounted in a high-vacuum cell allowing in situ outgassing, using a Thermo Nicolet Nexus 470 Fourier transform infrared (FTIR) instrument at 4 cm<sup>−</sup><sup>1</sup> resolution. The surface area was calculated by using the Brunauer– Emmett–Teller (BET) method based on the adsorption data in the relative pressure (p/po) range 0.05–0.35. The pore-size distribution was determined by using the Barrett–Joyner–Halenda (BJH) desorption model. Micropore volume was obtained by t-plot analysis. Total pore volume was obtained from the amount of nitrogen adsorbed at p/po = ca. 0.99. Mesopore volume was calculated by subtracting micropore volume from total volume. The water adsorption capacity of ZSM-5 zeolites was investigated in the experiments performed using a CI microbalance. The nitrogen adsorption and desorption isotherms at 77 K were measured using a QuadraSorb Station 2 version 5.13. The samples were outgassed for 3 h at 573 K before being measured.
