The Applications Research Of Reduced State Carbon Dots

Carbon dots (CDs), a new kind of fluorescent nanoparticles, were discovered serendipitously by researchers purifying single-walled carbon nanotubes in2004. Subsequently, this fluorescent nanoparticles which were dubbed CDs by Sun et al. have attracted extensive attentions. The scientists have made a large of work about the nanomaterials, including extending source, improving synthesized methods, but above efforts focused on improving the fluorescent property. CDs mainly have been applied in biolabeling and bioimaging. However, as an excellent electron acceptor and electron donor, CDs has promising potential to be an oxidizing or reducing agent, which have seldom been reported. There have chanllenges and important work for the applications of CDs. In process of improving quantum yield, our group synthesized reduced state carbon dots(r-CDs) successfully. We have applications research of the reduced state carbon dots:(1) It was confirmed that r-CDs acted as both reducer to reduce Au (Ⅲ) and capping agent to keep AuNPs from aggregating. The reducibility of r-CDs may derive from the hydroxyl groups on surfaces of r-CDs. And the capping ability can be attributed to the hydrogen binding between AuNPs and hydroxyl groups. Although the AuNPs we prepared exhibit less excellent catalytic activity in the reduction of4-NP with NaBH4, the AuNPs we prepared show higher catalytic activity than the AuNPs synthesized by citrate reduction for catalyzing oxidation of H2O2-TMB. Our findings open up a wide range of new potential applications for CDs in synthesis of metal nanomaterials.(2) Owing to gold nanomaterials exibit some noteworthy properties, such as surface plasmon resonance (SPR), surface enhanced raman scattering (SERS), the synthesis of anisotropic gold nanoparticles gold nanomaterials have attracted the interest of scientists. The r-CDs have been applied in synthesizing AuNPs and acted as both reducer and capping agent, based on above properties, we applied r-CDs to synthesize gold nanocubes. The lengths of the edges of the gold nanocubes were about74.9±9.3nm and gold nanocubes showed smooth surfaces, uniformity of the size.(3) We studied catalytic activity of the r-CDs, the results showed r-CDs existed could catalytically oxidize3,3’,5,5’-tetramethylbenzidine (TMB) by H2O2to produce a colour reaction. The effects of pH, temperature, the concentration of H2O2and TMB for catalytic activity, the catalytic rate constant (K) was0.00729min-1.