Table 2 Advantages and disadvantages of different methods
From: Synthesis of graphene quantum dots and their applications in drug delivery
| Â | Methods | Advantages | Disadvantages |
|---|---|---|---|
Top-down strategy | Chemical oxidation Method | It is widely used method at present; it is simple and effective and can be used in large-scale production | It usually needs to use H2SO4, HNO3 or other oxidants, which may cause corrosion or explosions |
Hydrothermal/solvothermal method | It is a green, simple and fast method | Reaction time is long; some raw materials need to be treated by strong oxidant before reaction occurs; reaction also involves high temperature and high pressure, which may cause combustion or explosion | |
Ultrasound assisted method | It can shorten the reaction time and improve the yield | It is difficult to synthesize on a large scale in industry | |
Electrochemical Oxidation Method | The GQDs produced are stable and uniform in size distribution | The pretreatment of raw materials and the yield of products is low, so it is difficult to carry out large-scale production | |
Other method | Â | It is difficult particle size control, low yield, long reaction time and complex process | |
Bottom-up strategy | Microwave method | It greatly shortens the reaction time and is green | It is difficult to carry out large-scale production and requires filtration and purification |
Molecular carbonization method | It is an environmentally friendly and simple method | It is impossible to control the size and structure of GQDs accurately; the obtained GQDs are multi-dispersive | |
Electron beam irradiation method | It is simple, fast and high yield | It requires expensive professional equipment and has the risk of being injured by radiation, so it has not been widely used |