Table 2.

Various Methods for Synthesis of MNPs

Routes	Methods	Condition	Temp (°C)	Duration (min/hrs/d)	Nano-Size	Capability of Morphology Control	Production Scale	Refs
Chemical	Co-precipitation	Facile in ambient conditions	20–150	Quick (min)	Small	Poor	Large	[80,81]
Chemical	Sol-gel synthesis	Difficult	25–200	Average (hrs)	Small	Good	Normal	[82,83]
Chemical	Electrochemical	Difficult	Room	Slow (hrs - d)	Small	Good	Normal	[84,85]
Green	Biosynthesis	Difficult	Room	Slow (hrs)	Average	Poor	Large	[86,87]
Green	Green-based	Easy	Room	Quick (min - hrs)	Small	Poor	Large	[20,37]
Physical	High-temperature thermal decomposition	Difficult	100–350	Slow (hrs - d)	Very small	Good	Large	[88,89]
Physical	Hydrothermal or solvothermal synthesis	Facile, High pressure	150–220	Slow (hrs - d)	Very small	Great	Large	[90,91]
Physical	Pulsed laser ablation pyrolysis	Difficult	Room	Quick (min - hrs)	Small	Good	Large	[92,93]
Physical	Microwave-assisted	Difficult	Room	Slow (hrs)	Average	Good	Normal	[94,95]
Physical	Microemulsion	Difficult	20–80	Average (hrs)	Small	Good	Small	[96,97]
Physical	Sonolysis or sonochemical	Very facile	20–50	Very quick (min)	Small	Poor	Normal	[98,99]
Physical	Aerosol/vapor	Difficult, controlled conditions	Above 100	Average (min- hrs)	Small	Good	Large	[100,101]