# Research Progress and Applications of 2D Antimonene
## 2 Theoretical Research and Experimental Methods
### Liquid Phase Exfoliation  
In 2008, graphene was successfully prepared for the first time by liquid phase exfoliation, in which a suitable solution was selected to remove the two-dimensional material [42]. This method has been used to study the preparation of antimonene since it was successfully stripped. In 2016, [PERSON] et al. [43] prepared antimonene with thickness multiple of 4 nm in isopropyl alcohol:water (4:1) mixture. The grinding antimony crystals were ultrasonically cleaned at 400 K for 40 min, and then centrifuged at 3000 rpm for 3 min. AFM (Atomic Force Microscope) measurement showed that the thickness was a multiple of 4 nm and the area was 1-3 \(\upmu\)m\({}^{2}\), as shown in Figure 3. However, the end of the sheet appears to be somewhat damaged, possibly due to solvent contamination, and it is noted that Raman spectrometric measurements depend on the thickness of antimonene. In 2019, they [44] studied the effects of grinding, solvent and ultrasound on the preparation of antimonene. Antimonene nanosheet samples were prepared, approximately 50% of which had a height  
Figure 2: (**a**) Exfoliation process of antimonene; (**b**) optical microscope images. The illustration is a larger view of the green box; (**c**) AFM appearance map; (**d**) the minimum thickness of the peel is 0.4 nm. Reprinted with permission from Ref. [39]. Copyright 2016, John Wiley and Sons. of 2-10 nm and a transverse size of 40-300 nm. The antimony was ground by wet ball method and treated with 400 W tip ultrasound for 40 min in 2-butanol (NPM:H\({}_{2}\)O = 4:1) and centrifugal at 3000 rpm for 3 min, as shown in Figure 4. Three methods of grinding antimony crystal, dry ball grinding antimony crystal and wet ball grinding antimony crystal were compared. Through SEM (scanning electron microscope) analysis, the crystal obtained by wet ball grinding in butanol has larger transverse size and smaller thickness and the highest suspension concentration. Wet ball grinding method and the same ultrasonic and centrifugal methods were used to compare the influence of solvents, and Figure 5 shows the peel values of different solvents. In NPM:H\({}_{2}\)O = 4:1, the concentration of the peel is approximately 0.368 g:L\({}^{-1}\), which is 30 times higher than the previous suspension concentration [45]. In butanol, however, there will be a higher DA value (DA: ratio between size and height value). At the same time, the effect of ultrasonic tip and ultrasonic bath on concentration and DA were compared, and the results showed that the tip ultrasound was better. The influence of different conditions on the preparation of antimonene in liquid phase separation and its better conditions were explored. Figure 4: The liquid phase exfoliation process of antimony is summarized, including the different steps. Firstly, different methods are used for pretreatment: (i) grinding bulk antimony crystals; (ii) dry ball milling bulk antimony crystals; (iii) wet ball milled bulk antimony crystals. Secondly, the solvent was selected based on the parameters using 28 different solvents, and thirdly, the ultrasound parameters were compared, including bath ultrasound and tip ultrasound. Arrows highlight the best route to obtain layers of antimonene with the highest concentration. Reprinted with permission from Ref. [44]. Copyright 2019, Royal Society of Chemistry. Figure 3: Height and size of antimonene prepared. Reprinted with permission from Ref. [43]. Copyright 2016, John Wiley and Sons. In order to reduce the thickness of antimonene thin films, [PERSON] et al. [46] prepared antimonene with a thickness of less than 2 nm and a transverse size of approximately 3 \(\upmu\)m by liquid-phase exfoliation method through pressure alloying. Through hydrothermal reaction using chemically active n-butyllithium, stable Li\({}_{3}\)Sb phase was formed at the edge of \(\beta\)-phase Sb, and then reacted with water to form gaseous SbH\({}_{3}\), thus promoting the subsequent separation.