Fe- and Co-doped lanthanum oxides catalysts for ammonia decomposition:Structure and catalytic performances

In this paper, a series of Fe- and Co-doped lanthanum(hydr)oxides catalysts were prepared by a simple coprecipitationhydrothermal method. The as-prepared catalysts were characterized with various techniques including powder X-ray diffraction(XRD), Nadsorption/desorption, inductively coupled plasma(ICP) and transmission electron microscopy(TEM). The Fe-based catalysts exhibited consecutive phase changes of amorphous Fe Ox→FeLaO→FeN under different stages(as-prepared→calcination→ammonia decomposition reaction); as for Co-based catalysts, the phase transformation followed a sequence of Co(OH)→CoO→metallic Co. It was revealed that FeN and metallic Co were most probably the active crystalline phase respectively for Feand Co-based catalysts in the decomposition of ammonia.