A 3D sandwich structured hybrid of gold nanoparticles decorated MnO2/graphene-carbon nanotubes as high performance H2O2 sensors

In this paper, a 3D sandwich structured hybrid of gold nanoparticles (AuNPs) decorated MnO2/graphene (GP)-carbon nanotubes (CNTs) was prepared via three steps, and the resultant AuNPs/MnO2/GP-CNTs hybrids was characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX) detector and X-ray diffraction (XRD) spectrum, respectively. In this structure, the peeled GP nanosheets from CNTs work as linkers with CNTs to form 3D scaffold for facilitating fast electron conduction. The MnO2 nanoparticles well distributed on the GP-CNTs scaffold have excellent electrocatalytic activities towards H2O2, serving as active materials for fabricating electrochemical H2O2 sensors. AuNPs ( < 10 nm) uniformly distributed on the MnO2 surface not only further enhance the electric conductivity, but also provide a second active material for sensing H2O2. As a result, taking full advantage of the synergistic effect among AuNPs, MnO2 and GP-CNTs scaffold, the as-prepared AuNPs/MnO2/GP-CNTs hybrids showed excellent electrocatalytic activity towards H2O2 with ultrahigh detection sensitivity of 452 μA mM−1 cm−2 and low detection limit of 0.1 μM (S/N = 3). In addition, the prepared H2O2 sensor was applied for the determination of real samples with satisfactory results, indicating that the prepared sensors are promising in practical application.