Rare earth intermetallics as synthetic ammonia catalysts

Abstract

The rapidity with which rare earth intermetallics absorb hydrogen suggests that they have high catalytic activity for the dissociation of molecular hydrogen and possibly other diatomic molecules such as N 2. Thirty-six intermetallics involving rare earths in combination with Fe, Co, or Ru were studied as catalysts for the formation of NH 3 from the elements. Several of these have specific activities exceeding that of a doubly promoted iron synthetic ammonia catalyst of the type in commercial use, although the actual activity is lower because of the relatively small surface area of the intermetallics. X-ray diffraction patterns of some of the intermetallics, notably the Fe-containing catalyst, showed extensive conversion into transition metal and rare earth nitride. The catalytic activities of these Systems may be due mainly to the transition elements.