Simple one-pot polyol synthesis of Pd nanoparticles, TiO2 microrods and reduced graphene oxide ternary composite for sensing NH3 gas at room temperature

Pd nanoparticles (Pd NPs), TiO2 microrods (TiO2 MRs) and reduced graphene oxide (RGO) ternary composite (Pd NPs/TiO2 MRs/RGO) film were fabricated by one-pot polyol, followed by annealing, to yield two morphologies of MRS and NPs. The NH3 gas-sensing properties of Pd NPs/TiO2 MRs/RGO film at room-temperature were investigated. The morphology, phase composition and crystalline structure of Pd NPs/TiO2 MRs/RGO ternary composite films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Microstructural observations revealed that the Pd NPs and interconnected TiO2 MRs randomly adhered to the surface of RGO. Comparative gas sensing results revealed that the sensor that was based on the Pd NPs/TiO2 MRs/RGO ternary composite film responded much more strongly to NH3 gas at room temperature than did that based on TiO2 MRs and TiO2 MRs/RGO films, revealing the contribution of RGO and Pd NPs to NH3 gas-sensing capacity. Most importantly, the sensor that was made of the Pd NPs/TiO2 MRs/RGO ternary composite film responded strongly to low concentrations of NH3 gas at room temperature; its use is practical because of its ease of fabrication. (C) 2017 Elsevier B.V. All rights reserved.