*3.2. Set-Up*

Reactions (DR, CC, and activation reaction) were conducted in a differential fixed-bed reactor, which is a quartz tube of approximately 25 cm of length and 15 mm of internal diameter, put in an oven with temperature control. The catalyst was deposited at the bottom of the tube between two pieces of quartz wool and placed in the oven. Gases were fed from commercial gas (supplied by Praxair) cylinders: C2H4 (99%), CO2 (99%) for the DR reaction, C2H4 (99%), Ar (99%) for CC reaction, and H2 (99%) and Ar (99%) for the activation reaction. Three AALBORG mass flow meters were used to control the gas flow at the inlet (Figure 31). The flow rate of the products was measured using a bubble flow meter and its composition was analyzed by gas chromatography (GC Varian CP-3800) with a measurement error varying between 1% and 2.5% depending on the analyzed gases (i.e., H2 had the highest error proven during calibration tests).

**Figure 31.** Reaction set-up [30].
