*2.7. The TEM Images of Ni-xSi/ZrO2 Catalysts*

The TEM images of reduced Ni-xSi/ZrO2 catalysts were presented in Figure 8. It can be seen that all the catalysts exhibited a similar morphology, and the particle sizes were distributed between 10 and 30 nm. From Figure 8B, Ni was more evenly distributed with particle sizes of 18–20 nm on the Ni-0.1Si/ZrO2 catalyst. However, on the Ni-1Si/ZrO2 catalyst, the size distribution of nickel particles was uneven, and there were big nickel particles. From Figure 8D, bulk particles were found on the Ni-1Si/ZrO2 catalyst, which might be bulk Ni particles or the mixture of Ni and Si.
