*3.3. Catalysts' Characterization*

XRPD patterns were performed at the speed of 8 ◦C min−<sup>1</sup> between 20◦ and 80◦ (2θ). TPR were performed between 30◦ and 900 ◦C in 5% H2/Ar (50 mL min<sup>−</sup>1) at the heating rate 10 ◦C min<sup>−</sup>1. TEM images, the EDS line scans and the corresponding element mapping scans analysis were performed to observe the component structure of the catalysts. The N2 physical adsorption curve were tested to calculate the BET surface areas, the pore size distributions, and the pore volumes of the catalysts. XPS profiles were used to analyze the binding energy of elements, and the binding energy (BE) of C 1s was 284.6 eV. TG was performed between 30 ◦C and 900 ◦C in air at the heating speed of 10 ◦C min<sup>−</sup>1. H2-TPD was used to analyze the dispersion degree and size of metal cobalt. The formula of d (Co0) = 96/D was used to calculate the size of metal cobalt, and the dispersion of metal cobalt was conducted by using the method reported in literatures [44,45].
