Table 1.

Common methods used in the synthesis of iron oxide nanoparticles, advantages and disadvantages, and references. Examples of isotropic and anisotropic shape nanoparticles are included.

Method	Advantages	Disadvantages	Ref.	Examples
Laser Ablation Synthesis in Solution (LASiS)	Green synthesis Different structures and composition	Difficult control of particle size and clustering	[27,28]	[29,30]
Chemical vapor deposition (laser and spray pyrolysis)	Easy to prepare Production of small particle size	Expensive equipment Gaseous interferences	[26,31,32,33]	[34,35,36,37]
Co-precipitation	Green Low-cost Scalable Facile Efficient	Difficult to control size Polydispersity Lack of precise stoichiometric phase control	[26,28,31,32,38]	[39,40,41]
Thermal decomposition	Small size particles Control of size and shape Monodisperse	Requires multiple steps Toxic solvents Toxic and expensive precursors Laborious purification Requires surface treatment after synthesis	[31,33]	[42,43]
Hydrothermal (solvothermal)	Green Versatile Control of morphology	Need of autoclave Control of dispersity Slow reaction kinetics	[28,33]	[44,45]
Sol-gel synthesis	Homogeneous Control of shape and length Low-cost High phase purity	Requires post treatment By-products Safety Low efficiency	[28,33]	[46,47]
Sonochemical decomposition	Mild experimental conditions Good crystallinity Versatile	Mechanism not still understood	[26,32,43]	[48,49]
Microemulsion	Monodispersity Simple equipment High control of size and shape Room conditions Small sizes	Removal of surfactants High solvent consumption Low-yield Difficult scale-up	[26,28,31,33]	[50]
Electrochemical synthesis	Control of particle size Simple and fast	Lack of reproducibility	[32]	[51,52]
Biosynthesis	High yield Reproducibility Scalability Low cost Room temperature	Time-consuming Laborious	[31,32]	[53,54]