Table 1 Different synthesis conditions and methods for shape-controlled ZnONSs

Mechanochemcal process

ZnCl2, Na2CO3, NaCl

400–800 °C

hexagonal structure, 18-35 nm

[28]

300–450 °C

51 nm particle

[21]

Precipitation Process

ZnSO4, NH4OH, NH4HCO3

2 h, 400 °C

hexagonal structure, flake-like, 60 nm

[29]

Zn (CH3COO)2, NaOH

30 min, 75 °C

hexagonal structure, flower-like, 800 nm

[30]

Zn (CH3COO)2, NH3 aq.

85 °C;

hexagonal structure, shape of rods, flower-like

[31]

ZnCl2, NH4OH, CTAB

aging: 96 h, calcination: 2 h, 500 °C

zincite structure, 54-60 nm

[32]

Sol-gel

Zn (CH3COO)2, oxalic acid (C2H2O4), Ethanol

4 h at 650 °C

hexagonal wurtize structure

[33]

Zn (CH3COO)2, diethanolamine, ethanol

2 h, 500 °C

hexagonal wurtize structure; nanotubes of 70 nm

[24]

Hydrothermal

Zn (CH3COO)2, NaOH, HMTA (hexamethylenetetraamine)

5–10 h, 100–200 °C

spherical shape, 55–110 nm

[23]

Microwave

Zn (NO3)2, deionized water, HMT (hexamethylenetetramine

2 min, 90 °C;

hexagonal wurtize structure, nanorod and nanowire shape (L: ~ 0.7 μm, D: ~ 280 nm);

[26]

Solvothermal

trimethylamine N-oxide, 4-picoline N-oxide, HCl, toluene, ethylenediamine (EDA), N,N,N′,N′-tetramethylethylenediamine (TMEDA)

24–100 h, 180 °C

wurtize structure; nanorods

[22]

Emulsion

Zn (CH3COO)2, heptanes, Span-80, NH4OH

aging: 2.5 h; calcination: 2 h, 700–1000 °C

hexagonal structure; spherical shape;, 0.05–0.15 μm

[34]

Microemulsion

Zn (NO3)2, NaOH, heptane, hexanol, Triton X-100, PEG400

15 h, 140 °C

hexagonal (wurtize) structure, needle (L: 150–200 nm, D: ~ 55 nm), nanocolumns (L: 80–100 nm, D: 50–80 nm), spherical (~ 45 nm)

[25]