*2.3. Catalyst Characterization*

BET specific surface area measurements were conducted on a Micromeritics Physisorption Unit (Gemini VI) by using a 300 mg sample. All of the samples were pre-treated before analysis to remove any impurities and subsequently analyzed under a liquid nitrogen atmosphere. X-ray diffraction (XRD) analysis of powder samples were carried out using a Rigaku (Miniflex) diffractometer equipped with radiation source of Cu Kα radiation which was operated at 40 kV and 40 mA. Temperature-programmed characterizations including desorption (TPD), reduction (TPR), and oxidation (TPO) were conducted using chemisorption apparatus (Micromeritics Auto Chem II apparatus). For H2-TPR, pretreatment of 50 mg of the catalyst sample was carried out under Argon (Ar) flowing at 20 mL/min at 150 ◦C for 30 min. Then, the sample was cooled down to room temperature before the temperature was raised to 1000 ◦C using a furnace and temperature ramp rate of 10 ◦C/min under mixture of 10%H2 in Ar flowing at 40 mL/min. For CO2-TPD measurements, same amount of sample (50 mg) was pretreated at 200 ◦C under helium (He) flowing at 20 mL/min for 1 h followed by cooling the sample down to 50 ◦C at which CO2 was adsorbed for 30 min by flowing mixture of 10%CO2 in helium at 30 m/min. The desorption profiles were recorded using thermal conductivity detector (TCD) by raising temperature linearly from 60 to 800 ◦C using 10 ◦C/min. Carbon deposition and type of graphitic carbon were analyzed using TPO experiments in which catalyst samples were pretreated at 150 ◦C for 30 min under helium flowing at 30 mL/min followed by cooling the samples down to room temperature. The oxidation profiles were measured by raising the sample temperature to 1000 ◦C using 10 ◦C/min under mixture of 10%O2 in helium flowing at 30 mL/min. The weight loss of the spent catalysts samples was analyzed using the thermogravimetric analysis (TGA) where 20 mg of each sample was subjected to heating under air from room temperature to 800 ◦C using 10 ◦C/min.
