Microwave synthesis of gold nanoparticles: Effect of applied microwave power and solution pH

We describe formation kinetics of gold nanoparticles (AuNPs) in microwave synthesis. Using high microwave power to increase the temperature ramping rate (Rr) homogeneous nucleation is facilitated and the size of the resultant nanoparticles is reduced while the uniformity is much improved. Adjusting solution pH to higher than 6.2 could also have a positive effect on the quality of the nanosol. We therefore demonstrate that by adjusting these reaction parameters in microwave synthesis, we successfully produced uniform colloidal AuNPs with diameter of 12.04 ± 1.35 nm in a few minutes.

► We investigated the formation kinetics of microwave synthesis of colloidal AuNPs.
► Using higher microwave power at initial stage, homogeneous nucleation is facilitated and the size of the resultant nanoparticles is reduced while the uniformity is much improved.
► Adjusting solution pH to higher than 6.2 by the sodium citrate/HAuCl4 ratio could also have a positive effect on the quality of the nanosol.
► Therefore, we successfully produced uniform colloidal AuNPs with diameter of 12.04 ± 1.35 nm in a few minutes.