Table 1.

Summary of different physical synthesis methods used in synthesized AgNPs.

Physical Method	Summary	Nanoparticle Size (nm), Shape	Ref.
Ball Milling	•Ag2O powder (99 %, 5–40 μm and graphite (99.9 %, 10–50 μm) •40 mol% of extra graphite as a reducing agent •Ball milling time 22 h	10,50 Round, Spherical	[69]
	•Inert gas atmosphere by purging Ar gas (1 Litre/h) in a milling chamber •Ball to powder ratio of 80:1 •Milling time 7 h	6–8 Spherical	[70]
	•Lignin and polyacrylamide (PAM) are used •Milling time 90 min, 30 Hz	1, 30 Spherical	[71]
	•Laser beam 532 nm •Pulse duration 50 ns •Repetition rate of 20 KHz •Auxiliary inert gas (Ar) is used	15 Spherical	[72]
	•Wavelength 1064 nm, •Energy 10 mJ •Pulse length 10 ns	9 Spherical	[73]
	•Wavelength 532 nm •Laser fluence 0.6 J/pulse	9–15 Spherical	[74]
	•Wavelength 1064 nm, •Repetition rate 10 Hz •Pulse length 8 ns	20–25, 48–51 Spherical	[75]
	•Wavelength 1064 nm •Pulse frequency 20 Hz and pulse duration 4 ns •Pulse energy 120 mJ	10 Spherical	[76]
	•Wavelength 532 nm and 1064 nm •Pulse duration 14 ns and 20 ns	10 Spherical	[77]
	•Pulses of 120 fs width at 1 kHz repetition rate centered •Wavelength 800 nm	1–3 Spherical	[78]
Gamma Irradiation	•Dose rate 1.2 kGy/h •0.5 % (w/v) stabilizers of polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin is used	4.3, 6.1, 7.6, 10.2	[79]
	•Dose rate 7.065 kGy/h •Source strength 13.455 kCi.	25 Spherical	[80]
	•Dose range 1 and 200 kGy •Dose rate of 3.3 kGy/h	1.4–3 Spherical	[81]
	•Dose rate 16.5 Gy min−1 •Irradiation dose 0.5 kGy	15 ± 3 Spherical	[82]
	•Dose rate 15 kGy	80, 100 Spherical	[83]
	•Irradiation doses of 20, 40, 80 and 120 kGy •Dose rate 3.48422 kGy/h	15–45 Spherical	[84]
	•Dose range 2.5 and 5 kGy •Dose rate of 7.628 kGy/h	–	[85]
Evaporation Condensation	•1500 °C in about 10 s at a local heating area of 5 × 10 mm2	6.2–21.5; 1.231, 88 Spherical	[67]
	•Evaporation temperatures 1123, 1273, 1423 K •Helium pressures of 0.5, 1, 5, 50, and 100 Torr	9–32 Spherical	[66]
	•Carrier gas liquid nitrogen	3–50 Spherical	[65]
	•Furnace at temperatures between 1,300 °C and 1,400 °C.	70, 150, 220	[68]