Urea-Based Synthesis of Zinc Oxide Nanostructures at Low Temperature

Table 1

Zinc species obtained by different synthesis method using urea as a precursor.

Synthesis method	Product 1	Temperature/time	Product 2	Morphology/size	Reference
Precipitation	Zn5(OH)6(CO3)2 + ZnO	4 h of synthesis	ZnO	Bipods/3.1–7.9 μm	[3]
Precipitation	[Zn(OH)2(H2O)2]	1000°C/2 h	ZnO	Hexagonal plates/35–45 μm	[6]
Sol-gel	Zn5(OH)6(CO3)2	500°C–900°C/2 h	ZnO	Spherical particles/20 nm	[28]
Conventional hydrothermal	white powder	550°C/4 h	ZnO	Column-, rosette-fiber-like/0,5–10 μm	[29]
Microwave-induced combustion technique	ZnO	—	—	Flowers-like/2–5 μm	[30]
Refluxing route	ZnO	—	—	Rods-likes/30–40 nm (diameter) and 500–700 nm (length)	[31]
Conventional hydrothermal	Zn5(OH)6(CO3)2	500°C/1 h	ZnO	Spherical particles/25 nm	[32]
Conventional hydrothermal	Zn4(OH)6CO3⋅H2O	400°C/2 h	ZnO	Flakes-like/0.65–1.5 mm	[33]
Conventional hydrothermal	Zn5(OH)6(CO3)2	600°C	ZnO	Flakes-like/10–20 nm	[11]
Solvothermal	ZnOCO3 + ZnO	180°C/24 h	ZnO	Spherical particles/50–300 nm	[23]
Urea aqueous solution process	Zn5(OH)6(CO3)2	600°C/30 min	ZnO	Spherical chrysanthemums/2–6 μm	[34]
Conventional water bath heating	ZnO	—	—	Irregular nanoparticles	This work
Microwave-assisted hydrothermal	ZnO	—	—	Spheres-like/85 nm	This work