Rapid and high sensitive detection of hexavalent chromium based on silver nanowire arrays SERS substrate

Toxic hexavalent chromium (Cr(VI)) can do great harm to human health and the ecological environment. Metal nanoparticle-based surface enhanced Raman scattering (SERS) can quickly detect chromium (Cr(VI)), but the SERS substrate is not uniform and the reproducibility is difficult to be guaranteed. A rapid, repetitive and highly sensitive method based on silver nanowire (AgNWs) arrays for the direct detection of Cr(VI) was proposed. Finite difference time domain (FDTD) theoretical simulation was applied to interpret experiment. The results demonstrate that the repeatability of our prepared AgNWs arrays with uniform "hot spots" is better than that of other reported nanomaterials. In addition, the SERS sensitivity and storage stability are outstanding. The detection limit of Cr(VI) is low down to 12.2 nM. In a certain range, there is an excellent linear correlation between logarithm concentrations of Cr(VI) ( R-2 = 0.99). The characteristic peaks of Cr(VI) gradually red shift with the decrease of its concentrations. Moreover, the uniform AgNWs arrays SERS substrates exhibit outstanding selectivity. The FDTD results support the experimental results well. These results demonstrate that the prepared AgNWs arrays SERS substrate have outstanding application prospect for rapid, highly sensitive, and on-site detection of Cr(VI).