Molecular sensing techniques for the characterization and design of new ammonia catalysts

The NN stretching frequency of adsorbed dinitrogen on the actual (supported or promoted) Ru catalysts has been shown to be extremely sensitive to the electronic state of the active surface which is usually hard to detect even by XPS. The wavenumber was also a good index of the N2 activation and ammonia synthesis on these Ru catalysts. Atomically adsorbed hydrogen and its effect on N2 activation was also observed by FTIR. The addition of alkali promotes N2 activation on Ru although it causes strong hydrogen poisoning. These various techniques have been discussed with regard to the development of the ‘second generation ammonia catalyst’.