Monodispersed and spherical silver nanoparticles/graphene nanocomposites from gamma-ray assisted in-situ synthesis for nitrite electrochemical sensing

Abstract

We designed a graphene oxide (GO) supported silver nanoparticles (AgNPs) nanocomposite via polyvinyl-pyrrolidone (PVP) and isopropanol (IPA) assisted gamma irradiation, in which GO contained abundant functional groups and AgNPs were endowed with monodispersed spherical shape. The graphite oxide was intercalated by the imidazole silver nitrate as the precursor, and then the AgNPs in the interlamellar of graphite oxide was reduced and grown via induction of gamma irradiation with IPA and PVP. Meanwhile, the size of AgNPs was limited by confinement effects of GO and fragmentation capability of gamma irradiation. IPA controlled the reduction of GO and the PVP endowed AgNPs with single crystal spherical structure and monodisperse size. And the as-prepared nanocomposites were applied in the nitrite detection as an electrochemical sensing platform. We found that the nanocomposites containing abundant oxygen-containing functional groups had a higher faradaic current than reduced nanocomposites. Spherical AgNPs decorated on GO obtained the most sensitive electrode among all samples and the detection limit for nitrite was 0.24 μM which preceded that of most reported materials. The as-prepared sensor was well selective to nitrite in presences of NaH2PO4, Na2SO4, NaCl, NaNO3 and Na2CO3. An effective approach was presented to develop the controllable synthesis of silver nanoparticle-functionalized graphene nanocomposites via gamma irradiation in application of electrochemical detection for nitrite ions in this work.