Hirabayashi S, Ichihashi M. Anomalously Efficient Dehydrogenation of NH
3 on Ir
4+ and Ir
5.
J Phys Chem A 2022;
126:4451-4455. [PMID:
35786880 DOI:
10.1021/acs.jpca.2c03316]
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Abstract
Gas-phase reactions of iridium cluster cations, Irn+ (n = 1-8), with ammonia are studied at near-thermal energies. In single collision reactions, dehydrogenation of NH3 proceeds at n = 1-5, and in particular, Ir4+ and Ir5+ are found to be significantly reactive. This size dependence is quite different from those of other platinum group metal cluster cations, where usually only the dimers are able to dehydrogenate NH3. Moreover, the sequentially dehydrogenated products, Ir4,5(NH)m+ (m = 2-5), are chiefly observed under multiple collision conditions. This observation suggests that the NH species on Ir4,5+ possibly encourages, or at least does not prohibit, the adsorption of the coming NH3 molecule and the dehydrogenation.
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