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 MnO 2 /graphene (GP)-carbon nanotubes (CNTs) was prepared via three steps, and the resultant AuNPs/MnO 2 /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 MnO 2 nanoparticles well distributed on the GP-CNTs scaffold have excellent electrocatalytic activities towards H 2 O 2 , serving as active materials for fabricating electrochemical H 2 O 2 sensors. AuNPs ( < 10 nm) uniformly distributed on the MnO 2 surface not only further enhance the electric conductivity, but also provide a second active material for sensing H 2 O 2. As a result, taking full advantage of the synergistic effect among AuNPs, MnO 2 and GP-CNTs scaffold, the as-prepared AuNPs/MnO 2 /GP-CNTs hybrids showed excellent electrocatalytic activity towards H 2 O 2 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 H 2 O 2 sensor was applied for the determination of real samples with satisfactory results, indicating that the prepared sensors are promising in practical application.