Table 1.

The summary of the top-down method for the fabrication of 2D MOXs

Synthesis methods	Advantages	Limitations	Materials	Thickness (nm)	Applications	Ref.
Mechanical exfoliation	Simple High quality	Low yield	h-TiO2	0.55	Electronic device	(Zhang et al., 2021a)
Ultrasonic-assisted liquid-phase exfoliation	Simple Economical Scalable	Poor controllability	Ga2O3	6	Photocatalyst	(Syed et al., 2017)
			MoO3	3–4	Supercapacitor	(Hanlon et al., 2014)
			V2O5	2.1–3.8	Lithium storage	(Zhang et al., 2017)
Cleavage plane-oriented exfoliation	Simple Economical	Poor scalability	TiO2	0.41	–	(Liu et al., 2019)
SC-CO2-assisted exfoliation	Amorphous structure	High cost	VO2	–	–	(Zhang et al., 2021b)
Soft chemical exfoliation	Simple Moderate	Low efficiency High cost	MoO3	5	Supercapacitors	(Sricharan et al., 2020)
Electrochemical exfoliation	Eco-friendly Efficiency High yield	Poor scalability	MnO2	0.73	Zinc-ion batteries	(Yang et al., 2021)
			ZnO	1	Gas sensor	(Hou et al., 2017)