Table 6.
Summary of microwave hydrothermal synthesis of ZnO nanostructures with additional heat treatment.
| Substrates | Conditions during Preparation | Parameters of Additional Heat Treatment | Properties | Ref. |
|---|---|---|---|---|
| Zn(CH3COO)2·2H2O, NH4OH, H2O | duration: 5–10 min; power: 240–400 W; microwave oven | 500 °C in air for 1 h | dumbbell-shaped structures built of particles sized ~100 nm | [641] |
| Zn(CH3COO)2·2H2O, KOH, H2O | duration: 15 min (irradiation 12 s, stop 10 s); power: 180 W; microwave oven | 400 °C in air for 1 h | nanorods assembled in flower shaped, rods: diameter 150–190 nm (tip diameter ~15 nm), length 2 μm, with an aspect ratio of 20–22 |
[642,643] |
| Zn(CH3COO)2·2H2O, NaOH, guanidinium carbonate, acetyl acetone (ACAC), H2O | pH: 8–12; duration: 2 min; power level: 75%; microwave oven | without and 600 °C in air for 2 h | petals: length 600–700 nm, width 300–400 nm, tip 50–70 nm; rod-like nanostructures diameters 60–90 nm maximal length 1.5 µm; spherical-like nanostructures: diameter 50 nm |
[644] |
| Zn(CH3COO)2·2H2O (0.2 M), NaOH (0.4 M), H2O, triethanolamine (TEA, C6H15NO3) | duration: 20 min; power: 20%; microwave oven | 900 °C in air for 1 h | spherical particles ~50 nm | [645] |
| Zn(NO3)2·6H2O, hexamethylenetetramine (C6H12N4), H2O | duration: 2 h; microwave oven | 250–550 °C for 1 h in oxygen flow (5 cm3/min) | nanorods (diameter from 50–300 nm) grown on surface of silicon substrates | [568] |
| Zn(NO3)2·6H2O, hexamethylenetetramine (C6H12N4), polyethylenimine, NH4OH, H2O | duration: 4–80 min; power: 180–850 W; microwave oven | 350 °C for 20 min in air | nanowire grown on an ITO-coated glass substrate | [646] |
| Zn(CH3COO)2·2H2O, NaOH, H2O | duration: 10 min; power: 200 W; microwave oven | 400–800 °C for 1 h in air | circular- and hexagonal-shaped particles | [647] |
| Zn(CH3COO)2·2H2O, sodium dodecyl, NH4OH, (CH3)2CHOH (2-propanol) H2O | duration: 2 h; power: 100–800 W; microwave oven | 500 °C for 3 h in air | flakes-like structures, spherical-like, crystallite size: 31–39 nm (morphology dependent on the microwave power) |
[648] |
| Zn(CH3COO)2·2H2O, ZnCl2·2H2O, Zn(NO3)2·6H2O, pyridine (C5H5N), H2O | pH: 13.75; duration: 2–5 min; power: 1000 W; microwave oven | 300–500 °C for 2 h in air | nanoparticles, nanoflowers, nanorods | [649] |
| Zn(CH3COO)2·2H2O, urea, H2O | T: 220 °C; duration: 15 min; microwave oven | 400 °C for 90 min in air | nanosheets | [650] |
| Zn(NO3)2·6H2O, hexamethylenetetramine (C6H12N4), NaOH, H2O | pH: 13; T: 90–220 °C; duration: 15 min; power: 110–710 W; microwave reactor (1400 W) | 200 °C for 2 h in air | nano-platelets | [651] |
| Zn(CH3COO)2·2H2O, trisodium citrate dihydrate (Na3C6H5O7·2H2O) (different amounts), NH4OH, H2O | T: 90 °C; duration: 10–45 min; power: 300 W; microwave reactor | 400 °C for 4 h in air | hollow microspheres average dimensions ~4 μm; thickness 400–600 nm. | [652] |
| Zn(NO3)2·6H2O, NH4OH, albumen, H2O | pH: 8; duration: 5 min; microwave oven (1000 W) | 130 °C for 5 h in air | whisker-like and rod-like nanostructures: thickness 10–57 nm | [585] |
| Zn(NO3)2·6H2O, KOH, H2O | pH: 9–13; duration: 30 min; power: 180 W microwave oven | 200 °C for 2 h in vacuum | nanorods | [653] |
| Zn(NO3)2·6H2O, urea (different concentrations), H2O | T: 90 °C; duration: 40 min; power: 400 W microwave oven | 400–600 °C for 3 h in different atmospheres (O2, N2, H2 and air), | various flower-like nano and microstructures, urchin-like structures | [654] |
| Zn(CH3COO)2·2H2O, NH4OH, hexamethylenetetramine ((CH2)6N4), hexadecyl trimethyl ammonium bromide, polyethylene glycol (PEG400), H2O | duration: 10 min; power: 300 W; microwave reactor | 500 °C for 2 h in air | needle-assembled structures with flower-like morphology; bundle-like microstructures assembled by nanorods; flower-like hierarchical structures composed of some tight aggregations |
[655] |
| Zn(CH3COO)2·2H2O, trisodium citrate dihydrate (Na3C6H5O7·2H2O), urea, H2O | T: 140 °C; duration: 20 min; microwave reactor | 500 °C for 2 h in air | porous core–shell microstructures | [656] |
| Zn(NO3)2·6H2O, NaOH, H2O, | pH: 13; duration: 1–5 min with 30 s on–off cycling mode; power: 900 W; microwave oven | 400 °C for 1 h in air | microspheres | [657] |
| Zn(CH3COO)2·2H2O, NaOH, H2O, | pH: 12.66–13; duration: 10–30 min; power: 300 W; microwave reactor | 500 °C for 2 h in air | nanorods, nanoplates | [658] |
| Zn(NO3)2·6H2O, hexamethylenetetramine (C6H12N4), H2O | duration: 45 min; power: 1800 W; microwave oven | 350 °C for 1 h in air | nanorods, length: ~4.3 ± 0.2 µm, diameter: 100 ± 10 nm | [659] |
| Zn(NO3)2·6H2O, hexamethylenetetramine (C6H12N4) (different concentrations), H2O | duration: 10 min; power: 750 W; microwave reactor | 400 °C for 1 h in air | shape from random spherical to highly conserved hexagonal shaped rods, size: from ~25 nm to µm/sub µm | [660] |
| Zn(NO3)2·6H2O, hexamethylenetetramine (C6H12N4), hydrazine hydrate (N2H4), H2O | pH: 10; duration: 10–30 min; microwave reactor (1000 W) |
500 °C for 2 h in air | nanorods, length: 579–909 nm, diameter: 116–240 nm | [661] |
| Zn(CH3COO)2·2H2O, Tuber (Amorphophallus konjac) extract, H2O | duration: 5 min; microwave oven | 400 °C for 1 h in air | rice shaped nanoparticles, length: 237 nm, diameter: 76 nm |
[662] |
| ZnCl2, NaOH, H2O | pH: 6.1–13.7; T: 80 °C; duration: 5–20 min; microwave reactor (900 W) | 150 °C for 3 h in air | hexagonal flake, velvet flower-like, rough globular, needle bunch-like, cauliflower-like, clew-like, nanorods, and rhombic microstructures | [663] |
| Zn(CH3COO)2·2H2O, ZnCl2·3H2O, Zn(NO3)2·6H2O, ZnSO4·7H2O, NH4OH, H2O | duration: 10 min; microwave reactor | 600 °C for 2 h in air | nanoflakes, nanorods, hexagonal tubular, pseudo-spherical | [664] |
| Zn(NO3)2·6H2O, NaOH, H2O (solvent) and C2H5OH (solvent) | P: 20–40 bars; duration: 15 min; microwave reactor |
750 °C for 1 h in air | particles, irregular shape | [665] |
| ZnCl2·3H2O, H2O, microcrystalline cellulose |
T: 100 °C; duration: 10–60 min; microwave oven |
600 °C for 3 h in air | heterogeneous nanostructures and microstructures | [666] |
| Zn(CH3COO)2·2H2O, ZnCl2·3H2O, ZnSO4·7H2O, ZnCO3, Psidium guajava Linn. Extract, H2O | T: 100 °C; duration: varying cycles of 3 min-on and 1 min-off min; power: 720 W; microwave oven | 900 °C for 1.5 h in air | diameter: 60–180 nm | [667] |
| Zn(NO3)2·6H2O, pelargonium leaf extract, H2O | duration: 3 min; power: 800 W; microwave oven |
400 °C for 2 h in air | heterogeneous particles | [668] |
| ZnSO4·7H2O (different concentrations), banana corm extract, H2O | duration: 15 min; power: 540 W; microwave oven | 400 °C for 3 h in air | microparticles | [669] |
| Zn(CH3COO)2·2H2O, KOH, H2O | duration: 0.5–2 min; microwave oven (1000 W) |
400 °C for 1 h in air | nanorods, tetrapods (length: 255 nm), flowers (petal length: 387 nm) | [670] |
| Zn5(OH)8(NO3)2·2H2O, 1,2,3- trimethyl-imidazole tetrafluoroborate, H2O | duration: 2 h; power: 180 W; microwave oven (900 W) | 400 °C for 2 h in air | nanobelts, width: 500–800 nm; length: several micrometres, thickness: 100 nm | [671] |
| Zn(CH3COO)2·2H2O, NH4OH, C2H5OH, H2O | T: 120 °C; duration: 10 min; power: 180 W; microwave reactor | 527 °C in air | heterogeneous hollow NPs, SSA: 17.1 m2/g | [672] |
| Zn(NO3)2·6H2O, NaOH, polyethylene glycols (MW= 1500 and MW= 4000), sugar, cassava starch, H2O | duration: 10 min (with 5 s/15 s on/off step); power: 320 and 480 W; microwave oven |
450 °C for 1 h in air | rod-like structures and needle-like structures, length: 300–3000 nm | [673] |