Synthesis and characterization of Sm3+-doped Y(OH)3 and Y2O3 nanowires and their NO reduction activity

A highly crystallized hexagonal structure with large aspect-ratios, almost uniform diameter and length of several tens of microns of Y(OH)3 nanowires, have been successfully synthesized by controlling the hydrothermal reaction time as well as an addition of 5 mol% Sm3+ at 180 °C for 24 h under N2 atmosphere. The hydrothermal products of yttrium nitrate precursor alone have showed merely nanosheets like structure under the same reaction conditions. The microstructures of the Y(OH)3 nanowires were studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution (HR)TEM and selected area electron diffraction (SAED). After heat treatment, the as-prepared Y(OH)3 could be completely transformed into Y2O3 while maintaining the nanowires structure up to the temperature at 400 °C in air. The Y2O3:Sm3+ have been tested for the reduction of NO under an oxidizing atmosphere with hydrocarbons. Moreover, the NO reduction activity under atmosphere containing water vapor was also investigated.