Use of positron-emitting nitrogen-13 for studies of the selective reduction of nitric oxide by ammonia over vanadia/titania catalyst at very low reactant concentrations

Positron emission imaging in catalysis

“…More recently Baiker and coworkers [20] used 1aN-labeled NO to investigate the selective catalytic reduction (SCR) of NO by NH3 over vanadia/titania at very low reactant concentrations. Concentrations of 5X 10 _9 ppm 13NO were used (10 n times lower than those typically used).…”

Thermochromatographic Investigation of 13N Labelled Nitrous Gases and of Fission Noble Gases at Low Temperatures

“…"N was produced in the reaction A gas target of 70 mm length consisting of a mixture of 580 ml/min He and 100 ml/min O2 was bombarded at the PSI PHILIPS cyclotron by 250 nA of 14 MeV protons [4], The gas mixture containing the reaction products was transfered through a 2 mm i.d. Polyethylene capillary over a distance of about 100 m to the thermochromatography device.…”

“…The production of the different "N labelled species is described in detail in Ref. [4]: The primary product from the target Chamber was mainly H^NOa, which was presumably formed with trace amounts of water vapour in the gas. HNO3 was converted to NO using a molybdenum Converter.…”

“…Behind the molybdenum Converter NO2 was produced from NO by oxidation with chromium trioxide soaked with phosphoric acid. Addition of ozone to the NO resulted in formation of HNO3, since concentrations of impurities such as H2O were high compared to the "NO concentration (10' molecules per cm^ [4]). …”

Positron Emission Profiling: a Study of Hydrocarbon Diffusivity in MFI Zeolites

“…The first use of positron-emitting isotopes as tracers in catalysis research was published in 1984 by Ferrieri and Wolf [27,28] for studying alkyne cyclotrimerization of acetylene and propylene. Baiker and co-workers [29] used 13 N-labeled NO to investigate the selective catalytic reduction (SCR) of NO by NH 3 over vanadia/titania at very low reactant concentrations.…”