*2.1. Design and Modification of the Rotary Furnace*

A novel rotary reactor has been designed for the manufacturing of IF-WS2 nanomaterials. The rotary reactor was designed based on a conventional tube furnace. The furnace is 1 m long and has a working temperature up to 1200 °C, which ensures a long enough hot zone for complete reactions at the required temperatures.

**Figure 1.** Sketch of the rotary furnace. In a traditional static furnace, the WO*x* particles stay still in the quartz tube at high temperature (800–900 °C), which leads to the dominance of 2H-WS2 in the final products; whilst in the present furnace, the quartz working tubes are rotating, forcing the WO3 and formed WS2 nanoparticles to rotate and move during the process, resulting in better separated IF-WS2 products at minimal agglomeration.

As shown in Figure 1, the rotary furnace consists of several essential parts: a basic tube furnace, a motorised driving and rolling system, an inclining system, a dynamic rotary seal system, a continuous feeding system and a collection system. The quartz working tube can be further modified to improve the batch yield. The working tube has inner diameter of 36 mm and outer diameter of 40 mm. Further modification was realised by adding two small oppositely positioned quartz rod blades of Ø5 mm to the inner wall (Figure S1), to provide extra forces driving the movement of powders inside the reactor. This would further eliminate particle agglomerations.

In order to extend the batch process to a continuous production, a continuous feeding system is required. In the current laboratory scale trial, after considering the existing screw feeding and piston feeding mechanisms [28–30], we adopted a simple pump piston feeder, which is more cost-effective. Actually, the current piston feeder under gravitation and gas blow works well in the current set up, since the slight vibration of the reactor helped avoid system blocking and keep a constant feeding. In industrial level, a proper, accurate screw feeder could be used to replace the current feeder. As shown in Figures 1 and S2, the feeder consists of a 20 mL push pump connected to a "T" junction, acting as the combined inlet blow gas and nanoparticle passage channel. The conceptual rotary furnace enables us to experiment with various parameters for optimal IF-WS2 manufacture. A simple collection system has also been designed, as shown in the dashed box in Figure 1, which makes the process continuous. The detailed schematic drawing of the collection system is shown in Figure S3. The key features of the practically assembled furnace are listed in Table 1.


**Table 1.** Key parameters of the designed furnace.

\*: depending on numbers of loaded pump container.
