Gas sorption. Low-pressure N2 isotherms (adsorption and desorption) were collected using an Anton Parr Autosorb iQ-XR at 77 K. An oven-dried sample cell (Type A long cell, 9 mm outer diameter, LG bulb) was tared before being loaded with a sample. Ex-situ degassing (110 °C, dynamic vacuum, 16 h) was performed before the evacuated tube was weighed again to determine the sample mass. Isotherms were collected over 24 -30 h, and the samples were reweighed following analysis to ensure accurate mass readings. Sorption isotherms were evacuated in AsiQwin version 5.21 software. Brunauer-Emmett-Teller (BET) surface areas were calculated from isotherms using the BET equation and Rouquerol's consistency criteria implemented in AsiQwin. Fourier-transform infrared spectroscopy (FT-IR). Spectra were recorded on PerkinElmer FT-IR Spectrometer in the region of 600 -3600 cm -1 .