Reaction properties of ruthenium over Ru/TiO2 for selective catalytic oxidation of ammonia to nitrogen

The objective of this study was to investigate reaction characteristics of selective catalytic oxidation of ammonia to nitrogen (NH3-SCO) using ruthenium-based catalysts. Ruthenium was compared with platinum, a metal generally used as an NH3 oxidation catalyst. Experiment was carried out by depositing active metal onto TiO2 center dot 1Ru/TiO2 was superior to 1Pt/TiO2 in NH3 conversion and N-2 yield. Therefore, various analyses were conducted to determine the influence of catalytic properties of 1Ru/TiO2 on reaction activity. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Field Emission-Transmission Electron Microscope (FE-TEM) analyses confirmed that ruthenium was present in RuO2. Such a structure was confirmed to be excellent for adsorption ability of NH3 and oxygen through analysis of NH3-TPD, NH3-TPO, H-2-TPR, and O-2 -chemisorption. In addition, in situ diffuse reflectance infrared Fourier transform spectroscopy (DIRFTS) analysis suggested that Ru/TiO2 had excellent ability to convert NH3 to NO. The converted NO then reacted with adsorbed NH3 to generate N-2. Based on results of NH3 injection at various concentrations, it was found that the rate at which NH3 was converted to NO from the Ru/TiO2 surface affected N-2 selectivity.