Effect of different reaction conditions and plant extract on the shape, size, and crystal structure of ZrO₂ NPs.

Plant	Zirconia source	Conc. of plant extract, precursor, ratio	Reaction temperature, time	Thermal treatment (drying and calcination)	Size range, average size (nm)	Crystal system, shape	Ref.
Euclea natalensis roots	Zirconyl chloride octahydrate	50 g L−1, 0.03 mol L−1, 1 : 1	–, 3 h	105 °C for 24 h, 550 °C for 3 h	5.25–41.71 nm, –	Monoclinic and tetragonal, spherical	57
Acalypha indica leaves	Zirconyl chloride octahydrate	100 g L−1, 0.1 mol L−1, 1 : 5	80 °C, 2 h	200 °C for 2 h, –	58–72 nm, –	Monoclinic, –	60
Azadirachta indica leaves	Zirconyl chloride octahydrate	100 g L−1, 50 mol L−1, –	50–60 °C, –	120 °C, 600 °C for 5–6 h	–, –	–, –	61
Aloe vera leaves	Zirconium oxychloride octahydrate	500 g L−1, 0.4 mol L−1, –	Room temperature, 4 h	–, 500 °C	27.4 nm, 50 nm	Tetragonal, spherical	67
Eucalyptus globulus leaves	Zirconium oxychloride	100 g L−1, 0.0098 mol L−1, 1 : 1	–, 2–3 h	80 °C, 600 °C for 3 h	9–11 nm, –	Monoclinic and cubic, spherical	68
Lagerstroemia speciosa leaves	Zirconium nitrate	150 g L−1, 0.2 N, 1 : 1	90 °C, 3 h	–, –	–, 56.8 nm	Tetragonal, –	65
Curcuma longa tuber	Potassium hexafluoro zirconate	25 g L−1, 0.00098 mol L−1, –	25 °C, 72 h	–, –	–, 41–45 nm	Monoclinic, –	62
Citrus aurantiifolia fruit	Zirconium(iv) acetate	10–30 mL, 0.038 mol L−1, –	90 °C, 3 h	–, 750 °C for 2 h	21 nm, 20 nm	Cubic, –	69