Synthesis of NH3 on Fe, Sm and Sm2Fe17 surfaces

Abstract Fe, Sm and Sm 2 Fe 17 films with amorphous-like structures were prepared under ultrahigh vacuum conditions. These metal surfaces were alternately exposed to H 2 or N 2 gas to measure the reactivities of the gases with the metals at 298 K. During the alternate gas exposures, NH 3 synthesis on the metal surfaces was examined by measuring the partial pressures in the system. NH 3 synthesis was detected during the H 2 exposure of an Fe surface with H 2 and N 2 pre-adsorption layers; during the N 2 exposure of an Sm hydride (SmH 2+ x ) surface; during the H 2 exposure of an Sm hydride (SmH 2+ x ) surface with N 2 pre-adsorption layers; and during the N 2 exposure of a surface of a hydrogen solution phase of Sm 2 Fe 17 (Sm 2 Fe 17 H 0.6 ). During the N 2 exposure of Sm 2 Fe 17 H 0.6 , rapid H 2 desorption from the sample was observed, indicating that the N atoms expel H atoms from the Sm 2 Fe 17 H 0.6 . Highly catalytic features of these modified metal surfaces are reported.