ИСТИНА

A facile route for production of highly stable 15-20 nm gold nanospheres using natural humic substances is reported. Evolution of gold nanoparticles was studied using a number of in situ and ex situ techniques. The revealed non-classical growth of gold nanospheres in presence of humic substances is quite similar to the one known for citrate-mediated route: gold nanocrystals grow within aggregates which then decompose to well-defined nanospheres. As opposed to citrate-capped gold nanoparticles, humic-stabilized samples can be handled as dry powder and easily redispersed in water on demand.