Polyphenols, in particular, are fundamental in the synthesis of nanoparticles due to the ability of their phenolic hydroxyl groups and oxygen atoms to form metal-phenolate complexes through chelating interactions . When these complexes are subjected to calcination at 400 °C, they decompose, resulting in the formation of nanoparticles. This behavior was also observed in the study by Sharma et al. , where the facility of polyphenols to donate electrons promoted the formation of the nickel-phenolate complex, which, after calcination, led to the production of NiO nanoparticles.