Silver nanoparticles (AgNPs) may be synthesized by many different methods, with those based on the thermal reduction of silver salts by citric acid or citric acid/tannic acid being amongst the most commonly used. These methods, although widely used and technically simple, can produce particles whose size, polydispersivity and morphology can vary greatly. In this work nearly mono-dispersed spherical AgNPs have been synthesized, via a one-step reduction method, by using sodium citrate and varying quantities of Tannic Acid (TA) which was thermally conditioned prior use in the growth process. It was found that the final size can be further tailored by controlling the amount of TA and, in addition, the thermal conditioning of the TA at 60°C at different time points, which changes the size and polydispersivity of AgNPs. To better understand the origin of this effect, optical spectroscopic analysis and 1H NMR of the TA following mild thermal conditioning of the solution have been done. Comparison of thermally conditioned TA and TA exposed to basic pH show that similar chemical modifications occur and consequently produce similar effects on growth when used in the synthesis of AgNPs. It is proposed that thermal pre-conditioning of the TA introduces either chemical or structural changes, which decrease the final particle size under a given total silver content.

LA SPINA Rita;  MĖHN Dóra;  FUMAGALLI Francesco;  HOLLAND Margaret;  RENIERO Fabiano;  ROSSI Francois;  GILLILAND Douglas; 

2026-07-08

MDPI

JRC97531

2079-4991 (online),   

https://www.mdpi.com/2079-4991/10/10/2031,    https://publications.jrc.ec.europa.eu/repository/handle/JRC97531,   

10.3390/nano10102031 (online),