Au/MOx (M = Zn, Ti) nanocomposites as highly efficient catalytic filters for chemical gas sensing at room temperature and in humid atmosphere

Abstract

Metal oxide supported gold nanoparticles (Au/MOx) have been prepared using deposition-precipitation with urea (DPU) method on commercial ZnO and TiO2 powders. These Au/MOx nanocomposites have been characterized by X-ray powder diffraction, high resolution transmission electron microscopy, nitrogen adsorption-desorption isotherms, and inductively coupled plasma atom emission spectroscopy. They have been used at room temperature as catalytic filters for CO oxidation in humid atmosphere (RH 40%). The CO removal efficiency has been evaluated using metal oxide gas sensors (MOS) device. The catalytic performances assessment of these Au/MOx nanocomposites highlights the efficiency of the Au/ZnO system. An integrated sensing device comprising the gas sensor and its catalytic filter has been developed. In that case, a plastic holder filled with low amounts (50mg) of Au/ZnO catalytic filter is simply placed above the MOS sensor. This system allows the improvement of the selectivity of the MOS sensors towards other gases, i.e. propane. The presented setting can be applied as one of valuable addition for multi-array sensor devices.