Effect of different chemical synthesis methods and reaction conditions on the shape, size, and crystal structure of ZrO2 NPsa.
| Chemical method | Materials | Solvent | pH | Reaction temperature/power and time | Thermal treatment | Crystal system, shape, size range, average size | Ref. |
|---|---|---|---|---|---|---|---|
| Microwave-assisted method | Zirconium oxychloride octahydrate, sodium hydroxide | — | — | 80 °C, 12 min | 400 °C, 2 h | Mixed phase (monoclinic and tetragonal), spherical (8–10) nm, 8.8 nm, – | 41 |
| Zirconium oxychloride, anhydrous citric acid | — | 2 | –, 2 min | 450 °C, 4 h | Tetragonal, –, –,∼5–10 nm | 42 | |
| Zirconium oxychloride, sodium hydroxide | — | 12 | –, 6 min | 600 °C, 4 h | Monoclinic, –, 32–38 nm, – | 43 | |
| Zirconyl nitrate monohydrate, l-serine amino acid | Water | — | 800 W, 60 s | 400 °C, 600 °C, 800 °C, – | Cubic, –, –, 70, 76 and 77 nm | 44 | |
| Zirconium oxychloride octahydrate | Water | — | 100–1000 W, – | –, – | Tetragonal, –, –, – | 19 | |
| Zirconium oxychloride octahydrate, honey | Water | — | ∼100 W, – | –, – | Tetragonal, –, –, ∼26 nm | 18 | |
| Zirconyl oxynitrate | 1,4-Butanediol | — | 800 W, 10 min | –, – | Tetragonal, –, –, ∼10 nm | 20 | |
| Hydrothermal method | ZrO(NO3)2·xH2O, sodium hydroxide | — | — | 150 °C, 4 h | 110 °C, 90 min | Monoclinic, –, –25 nm | 23 |
| Zirconyl chloride octahydrate, glucose monohydrate | Water | — | 180 °C, 20 h | 550 °C, 4 h | –, sphere, –8 nm, – | 26 | |
| Commercial zirconia, sodium hydroxide | — | — | 150 °C, 85 h | –, – | Mixed phases (monoclinic, tetragonal and cubic), –, –, 15–30 nm | 12 | |
| Zirconium oxychloride, sodium hydroxide | Ethanol and water | 14 | –, – | 400 °C and 500 °C, 2 h and 0.5 h | Tetragonal, –, 2–11 and 3–12 nm, 4.5 and 6 nm | 21 | |
| Zirconyl nitrate, CTAB/SDS/triton, ammonium hydroxide | — | 12 | 90 °C, 12 h | 500 °C, 2 h | –, varied, varied, – | 27 | |
| Sol–gel | Zirconium(iv) propoxide, acetic acid, nitric acid | Isopropanol | 2.5 | –, – | 700 °C, 1 h | Monoclinic, –, 25.39 nm, – | 32 |
| Zirconium(iv) propoxide, nitric acid | — | — | –, 1 h | 500 °C, 2 h | Tetragonal, –, –, 30–60 nm | 33 | |
| Zirconium n-propoxide, glucose, fructose, aqueous ammonia | — | 9–10 | RT, 1 h | 700 °C, 3 h | Tetragonal and monoclinic, –, 10–30 nm, – | 13 | |
| Zr(SO4)2·H2O, sodium lauryl sulfate | Benzyl alcohol | — | — | 600 °C, 5 h | Tetragonal and monoclinic, –, 9.7 nm, – | 45 | |
| Zr(acac)4, sucrose | Ethanol | ∼12 | 110 °C, 10 min | 300–650 °C, – | Tetragonal and monoclinic, –, –, – | 35 | |
| Co-precipitation | Zirconium nitrate hexahydrate, potassium hydroxide | Water | >10 | RT, – | 900 °C, 4 h | –, spherical (193 nm), –, – | 38 |
| Zirconyl chloride octahydrate, diammonium oxalate monohydrate, ethylene glycol | Water | — | Varied, varied | Varied, varied | Monoclinic, spherical, –, 12.85 nm | 39 | |
| Zirconium(iv) nitrate, tetraethyl ortho-silicate, ammonium hydroxide | Water and ethanol | 7 | 348 K, 10 min | 1173 K, 10 min | Tetragonal, –, 3.3 nm, – | 40 |
a
RT: room temperature.