*3.2. Catalysts Characterization*

Surface area and pore volume were obtained from N2 adsorption-desorption isotherms at 77 K performed on a Quanta chrome autosorb-1 analyzer. Before analysis, the samples were dried at room temperature and then vacuum degassed at 300 ◦C for 5 h. X-ray diffraction (XRD) patterns were obtained on a Bruker D8 Advance diffractometer with a copper Kα radiation source operated at 40 kV and 40 mA. During the analysis, the catalysts were scanned from 20◦ to 80◦ at a speed of 5 ◦/min. Furthermore, temperature-programmed reduction (TPR) profiles of fresh catalysts under H2-blanket were carried out using a TP-5076 TPR instrument. The samples (100 mg) were heated to 400 ◦C at a heating rate of 8 ◦C/min in a flow of Ar, kept for 45 min, and then cooled to 30 ◦C. The flow gas was switched to H2 (5%) in Ar (25 mL/min). The reduction was carried out from 30 ◦C to 920 ◦C, at a heating rate of 8 ◦C/min. NH3-temperature-programmed desorption (NH3-TPD) experiments were performed in a TP-5076 TPD instrument (Tian Jin Xian Quan Instrument Co., Ltd., Tianjin, China) equipped with a thermal conductivity detector (TCD) to investigate the surface acidity of catalysts. Prior to analysis, catalysts were pretreated at 400 ◦C for 1 h in a flow of N2 to clean the catalyst surface and then cooled to room temperature. After the pretreatment, a 2% NH3/N2 gas mixture was passed through the sample at 20 mL/min and the temperature was raised from 50 to 750 ◦C at a heating rate of 8 ◦C/min. In addition, morphological characterization was examined by field emission scanning electron microscopy (FESEM) using a Quanta 600FEG Field emission scanning electron microscope (FEI, Hillsboro, OR, USA) and coupled with Oxford-IE-250 energy dispersive spectrometer (EDS) for local elemental composition determination.

Transmission electron microscope (TEM) analysis was obtained using a FEI titan themis 200 transmission electron microscope (FEI, Hillsboro, OR, USA) equipped with Bruker super-X energy-dispersive spectrometer (EDS). Prior to measurement, the samples were dispersed in ethanol at first and then collected on a Cu grid which was covered with carbon film.

#### *3.3. Catalytic Performance Test*

*n*-decane steam reforming reaction was carried out in a fixed-bed stainless steel tubular reactor (i.d. = 12 mm) at atmospheric pressure. 3.0 g catalyst diluted with equi-volume quartz particles was charged for each catalytic assessment. The schematic diagram was shown in Figure 9. In each run, water and *n*-decane were pre-mixed quantitatively at 350 ◦C and the mixture vapor was fed into the reactor. The volumetric feed flow of water and *n*-decane are both 2.5 mL/min. The reactor was set at 650 ◦C, 700 ◦C, 750 ◦C or 800 ◦C respectively for evaluating the catalysts' activity.

**Figure 9.** Schematic diagram of apparatus. 1-feed tank; 2-water tank; 3-high pressure metering pump; 4-filter; 5-check valve; 6-mass flow meter; 7-heating system; 8-mixer; 9-reactor; 10-cold trap; 11-gas-liquid separator; 12-gas chromatograph; 13-liquid receiver; 14-wet gas flow meter.

The reaction effluents were on-line analyzed by Gas Chromatography with FID detector (GC-2010, SHIMADZU Co., Ltd., Kyoto, Japan) equipped with HP-Al/S separation capillary column (CH4, C2H4, C2H6, C3H8, C3H6, C4); and TCD detector with TDX-01 packed column (H2, CO and CO2). Solid products deposited covering the catalysts were investigated by temperature programmed oxidation (TPO), and the characteristics signals of CO and CO2 were tested by IR analyzer.

Activity data were reported as *n*-decane conversion *XA* (%), and H2, CO and CO2 selectivity (*Si*), which are defined as follows:

$$X\_A(\%) = \frac{\Delta \mathbf{m}\_A}{\mathbf{m}\_{A,in}} = \frac{\mathbf{m}\_{A,in} - \mathbf{m}\_{A,out}}{\mathbf{m}\_{A,in}} \times 100\tag{1}$$

$$S\_i = \frac{\text{moles}P\_i}{\sum\_{i=1}^n molesP\_i} \times 100\% \tag{2}$$

where *i* represents the different gas products detected.
