Investigation of NOx reduction activity of Rh/ZnO nanowires catalyst

The main pollutant exhaust emissions from gasoline engines are HCs, CO, and NOx. Today, the removal of NOx known to cause the formation of ground-level ozone, acid rain and smog is the most significant issue. The stringent emission regulations require that the emission of NOx is limited. In this study, the catalyst was prepared by impregnating Rh on the ZnO NWs grown on monolith cordierite channels in order to investigate in particular its NOx reduction activity and potential of ZnO nanowire structures to be used as monolith catalyst carrier. ZnO nanowire arrays have different morphology and effective porosity. Furthermore, thickness of ZnO nanowire arrays are less than traditional wash coat. Therefore, the ZnO nanowire arrays can be used as alternative monolith catalyst carrier. The structure of the catalyst was examined by SEM and XRD. Activity tests were performed under lean, stoichiometric and rich conditions in order to examine specifically NOx reduction activity of the finished catalyst. The NO reduction activity of the Rh/ZnO NWs catalyst decreases with the increasing oxygen in the gas mixture. This situation is expected in case of excessive oxygen in TWC reactions.