Green biosynthesis of gold nanoparticles by Lilium casa blanca petals and evaluation of catalytic activity

A simple, fast, and eco-friendly method for the biosynthesis of gold nanoparticles (AuNPs) using Lilium casa blanca petals as a reducing and protecting agent was reported. The heating time had been shortened to 30 min for biosynthesis of AuNPs, which only took 15 mg Lilium casa blanca petals powder. The biosynthetic AuNPs, which had a uniform particle size distribution, were in spherical with the average size of 5.933 ± 1.158 nm. In addition, the conversion rate of Au 3+ to Au 0 was quite high. Through the discussion on the nutrients' concentrations before and after the synthesis, it was found that sugars, alkaloids, flavonoids, and proteins were the reducing and stabilising agents. The biosynthetic AuNPs had good catalytic activity, taking the hydroboration of nitrophenol and methylene blue as examples. Catalytic reduction followed pseudo-first-order kinetics. Moreover, the apparent rate constant was a linear correlation with the concentrations of AuNPs. The normalised rate constant of the proposed AuNPs was higher than other reported AuNPs, which indicated the excellent catalytic activity. All the results foreshowed the wide range of applications of the biosynthetic AuNPs by Lilium casa blanca petals.