*3.2. Catalyst Characterization*

A detailed description of the instrumentation and procedures employed for catalyst characterization—by means of N2 physisorption, XRD, TGA, TEM-EDS, TPR, and DRIFTS—can be found in previous contributions [13,15,45]. Briefly, XRD measurements were performed on a Phillips X'Pert di ffractometer using Cu K α radiation (λ = 1.5406 Å) and a step size of 0.02◦. TGA was performed on a TA instrument Q500 thermogravimetric analyzer under flowing air (50 mL min−1) by ramping the temperature from room temperature to 1000 ◦C at a rate of 10 ◦C/min. TEM observations were conducted using a Thermo Scientific Talos F200X analytical electron microscope equipped with a SuperX EDS system consisting of 4 windowless silicon drift detectors (SDD) for quantitative chemical composition analysis and elemental distribution mapping. XPS analyses were performed using a PHI 5000 Versaprobe apparatus with monochromatic Al K α1 X-Ray source (energy of 1486.6 eV, accelerating voltage of 15 kV, power of 50 W and spot size diameter of 200 μm). Pass energies of 187.5 eV and 58.7 eV were used for survey spectra and high-resolution windows, respectively. The signal for Al2O3 (Al2p at 74.4 eV) was employed for energy calibration purposes (measurements being performed with a neutralization system). Spectra were processed with the CasaXPS software package, ionization cross-sections from Landau being used to quantify the semi-empirical relative sensitivity factors. Prior to analysis, powders were deposited on a steatite sample holder made in house. This sample holder enables the transfer of samples between a pre-treatment chamber and the XPS analysis chamber without exposure to air. The pre-treatment chamber—which was also designed and manufactured in house and is equipped with a furnace that can heat samples up to 1050 ◦C—can be filled with pre-treatment gases (up to 1 bar) and be placed under vacuum, which is done prior to transferring pretreated samples to the XPS analysis chamber.

### *3.3. Continuous Fixed-Bed Deoxygenation Experiments*

Used cooking oil upgrading experiments were performed in continuous mode using previously described equipment and procedures [11]. Briefly, a fixed-bed stainless-steel tubular reactor (1/2 in. o.d., Parr, Moline, IL, USA) with a stainless-steel porous frit to hold the bed—0.5 g of catalyst and 0.5 g of SiC as a diluent (or 1 g of SiC in the blank run)—in place was employed. Prior to each deoxygenation experiment, the catalyst to be tested was reduced in situ for 3 h at 400 ◦C under 40 bar of flowing H2 (60 mL/min). The same pressure and H2 flow were used during deoxygenation experiments, which were performed at 375 ◦C. The feed was introduced to the reactor—as a solution of 75 wt.% UCO in dodecane (>99% Alfa Aesar, Haverhill, MA, USA)—at a rate of 0.75 mL/h (equivalent to a WHSV of 1 <sup>h</sup>−1) using a Harvard Apparatus (Holliston, MA, USA) syringe pump equipped with an 8 mL syringe. Liquid products were sampled from a liquid-gas separator (kept at 0 ◦C) placed downstream from the catalyst bed. Incondensable gases were directed to a dry test meter before being collected in Tedlar ® gas sample bags. Gas sample bags were changed every time a liquid sample was taken to ensure that the gas samples analyzed and the liquid samples collected could be correlated. A blank (sans catalyst) experiment was conducted using 1 g of SiC. Representative experiments were performed in duplicate to ensure reproducibility. The highest average standard deviation values observed in the amount of diesel-like and heavier hydrocarbons formed were ±6.15% and ±5.66%, respectively.

### *3.4. Analysis of Reaction Products*

Liquid products were analyzed using a combined simulated-distillation-GC and GC-MS approach. A detailed description of the development and application of this method is available elsewhere [46]. Briefly, the analyses were performed using an Agilent 7890B GC system equipped with an Agilent 5977A extractor MS detector and flame ionization detector (FID). The multimode inlet was run with an initial temperature of 100 ◦C. Upon injection, this temperature was immediately increased at a rate of 8 ◦C/min to 380 ◦C, which was maintained for the remainder of the analysis. The oven temperature was increased upon injection from 40 ◦C to 325 ◦C at a rate of 4 ◦C/min, followed by a ramp of 10 ◦C/min to 400 ◦C, which was maintained for 12.5 min. An Agilent J&W VF-5ht column (30 m × 250 μm × 0.1 μm) rated to 450 ◦C was used. Gaseous samples were analyzed using an Agilent (Santa Clara, CA, USA) 3000 Micro-GC equipped with 5 Å molecular sieve, PoraPLOT U, alumina, and OV-1 columns, as well

as with a universal thermal conductivity detector (TCD). The GC was calibrated for all of the gaseous products obtained, including CO and CO2, as well as straight-chain C1–C6 alkanes and alkenes.
