Tuning the pure monoclinic phase of WO_3 and WO_3-Ag nanostructures for non-enzymatic glucose sensing application with theoretical insight from electronic structure simulations

摘要

Here, we report the controlled hydrothermal synthesis and tuning of the pure monoclinic phase of WO_3 and WO_3-Ag nanostructures. Comparative electrochemical nonenzymatic glucose sensing properties of WO_3 and WO_3-Ag were investigated by cyclic voltammetry and chronoamperometric tests. We observed enhanced glucose sensing performance of WO_3-Ag porous spheres as compared to bare WO_3 nanoslabs. The sensitivity of the pure WO_3 nanoslabs is 11.1 μA μM~(-1) cm~(-2) whereas WO_3-Ag porous spheres exhibit sensitivity of 23.3 μA μM~(-1) cm~(-2). The WO_3-Ag porous spheres exhibited a good linear range (5-375 μM) with excellent anti-interference property. Our experimental observations are qualitatively supported by density functional theory simulations through investigation of bonding and charge transfer mechanism of glucose on WO_3 and Ag doped WO_3. As the binding energy of glucose is more on the Ag doped WO_3 (100) surface compared to the bare WO_3 (100) surface and the Ag doped WO_3 (100) surface becomes more conducting due to enhancement of density of states near the Fermi level, we can infer that Ag doped WO_3 exhibits a better charge transfer media compared to bare WO_3 resulting in enhanced glucose sensitivity in consistency with our experimental data.