Table 4. Various properties of metal nanoparticles with NaBH₄.

Properties	Iron nanoparticles	Silver nanoparticles	Gold nanoparticles
Metal ion reduction	Fe3+/Fe2+ → Fe0	Ag+→ Ag0	Au3+ → Au0
Reduction kinetics	Very sensitive to reaction conditions; somewhat sluggish	Quick and effective; rate rises with concentration of NaBH4	Due to Au3+'s great reduction potential, it happens quite quickly
Role of NaBH4 in dye degradation	Keeping the atmosphere reductive and providing electrons for the reduction of dyes	Provides electrons by surface-assisted oxidation; AgNPs effectively transfer electrons	Serves as a constant supply of electrons; AuNPs transfer electrons to dye molecules
e− Transfer mechanism	FeNPs serve as less effective electron relay hubs	AgNPs facilitate quick electron transfer, which is amplified by plasmonic effects	AuNPs serve as mediators and stable electron stores
Concentration of NaBH4	Aids in reducing oxidation, but is unable to completely stop instability	Can result in borate aggregation or surface blockage	Generally steady, minimal negative impact