*3.4. Catalysts' Performance*

The CO hydrogenation performance of catalysts were tested in a fixed-bed reactor; 0.4 g samples and 0.4 g quartz sand in 40–60 mesh were mixed and used for the HAS reaction. Temperature, pressure and gas hourly space velocity were set to 290 ◦C, 4 MPa and 6000 mL·gcat−1·h<sup>−</sup>1, respectively. The molar ratio of H2/CO is 2/1, and the internal standard gas of reaction was N2. Before reaction, the catalysts precursors were reduced at 750 ◦C and remained 3 h in pure H2 atmosphere. A TCD detector was used for analyzing H2, N2, CO, CO2, and CH4; the hydrocarbons and alcohols were detected by

using a FID detector. The following formula is used to calculate CO conversion (XCO), the selectivity to product (Si), and the weight fraction to product (Wi):

$$\chi\_{\rm CO} = \frac{\rm CO\_{\rm in} - \rm CO\_{\rm out}}{\rm CO\_{\rm in}} \times 100\% \tag{1}$$

$$\text{S}\_{\text{i}} = \frac{\text{nC}\_{\text{i}}}{\sum \text{nC}\_{\text{i}}} \times 100\% \tag{2}$$

$$\mathbf{W\_{i}} = \frac{\mathbf{m\_{i}}}{\sum \mathbf{m\_{i}}} \times 100\% \tag{3}$$

COin and COout represent the moles fraction of CO in the inlet and outlet gases, respectively; n is the carbon atoms number, and Ci is the mole fractions of carbon-containing products. mi is the weight of alcohol.
