Table 1.

Summarized sizes and morphologies of MnO₂ NSs synthesized by different approaches

Method	Reaction materials	Morphology	Lateral dimensions	Thickness	Reference
Top-Down	H0.13MnO2·0.7H2O + TBAOH	Nanosheet structure	<50 nm	0.91±0.07nm	24
Bottom-Up (reductive)	KMnO4+ MES	Nanosheet structure	141 nm	~1.5 nm	28
Bottom-Up (reductive)	KMnO4+ SDS	Single-layered nanosheet	~200 nm	0.77–0.95 nm	29
Bottom-Up (oxidative)	MnCl2+ EDTA + NaOH	Thin film of nanosheet	2–5 µm width	~10 nm	27
Bottom-Up (oxidative)	MnCl2+ TMA.OH	Single-layered NS	<200 nm	Nearly 80% <1 nm	25
Bottom-Up (oxidative)	MnCl2+ H2O2+ TMA.OH	A two-dimensional sheet structure	~200 nm	~1.3 nm.	111
Bottom-Up (oxidative)	MnCl2+ (NH4)2S2O8+ TMA.OH	Flat morphology	2 µm	~4.07 nm	35
Bottom-Up (oxidative)	MnCl2+ H2O2+ TMA.OH	A sheet-like structure	N/A	~1.5 nm	36
Bottom-Up (oxidative)	MnCl2+ H2O2+ TMA.OH	Nanosheet structure	100–200 nm	N/A	69
Bottom-Up (oxidative)	MnCl2+ H2O2+ TMA.OH	Polycrystalline sheet structure	141 nm	1.5 nm	150
Bottom-Up (oxidative)	MnCl2+ H2O2+ TMA.OH	Single-layer sheet structure	200 nm	~1.5 nm	170

Abbreviations: TMA^.OH, tetramethylammonium hydroxide; TBA^.OH, tetrabutylammonium hydroxide; NS, nanosheet.