Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

A rational design approach was used to develop an alloyed Ni-Fe/Al2O3 catalyst for decomposition of ammonia. The dependence of the catalytic activity is tested as a function of the Ni-to-Fe ratio, the type of Ni-Fe alloy phase, the metal loading and the type of oxide support. In the tests with high temperatures and a low NH3-to-H2 ratio, the catalytic activity of the best Ni-Fe/Al2O3 catalyst was found to be comparable or even better to that of a more expensive Ru-based catalyst. Small Ni-Fe nanoparticle sizes are crucial for an optimal overall NH3 conversion because of a structural effect favoring the smallest particles in terms of catalytic activity per active site. Compared with SiO2, ZrO2 and TiO2, the support materials Al2O3 or Mg-Al-spinel give the highest performance in the high temperature range.

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► Non-noble metal Ni-Fe alloy catalysts for NH3 decomposition.
► Promising catalysts for high temperature NH3 decomposition.
► Structural sensitivity: increasing activity for decreasing particle sizes.
► Of various support oxides: Al2O3-based support materials give the best performance.