1 Department of Energy Conversion and Storage, Technical University of Denmark2 Imaging and Structural Analysis, Department of Energy Conversion and Storage, Technical University of Denmark3 Department of Physics, Technical University of Denmark4 Experimental Surface and Nanomaterials Physics, Department of Physics, Technical University of Denmark5 Amminex Emissions Technology A/S
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.
Applied Catalysis A: General, 2012, Vol 447-448, p. 22-31