Catalytic decomposition of hydrazine on palladium

The catalytic decomposition of hydrazine on pure Pd surfaces (polycrystalline wire) was investigated using mass spectrometry in an UHV system. Additional information was obtained from isotope exchange experiments with deuterium and from the acquisition of thermal desorption spectra. The hydrogen isotope exchange begins at room temperature and proceeds involving Daa according to a Langmuir-Hinshelwood mechanism. During the steady-state decomposition, N2, H2, and NH3 are formed in comparable amounts following a first-order reaction. The reaction proceeds nearly completely at 450°C. The ammonia yield increases with the addition of hydrogen proportional to √pH2. A reaction mechanism is proposed in which N2H4 -> N2H3 + H represents a crucial partial reaction, and NH3 is formed through stepwise hydrogenation of N2H4.