Low-temperature ortho-para conversion of hydrogen on films of rare-earth metals and their copper alloys

Abstract

Kinetic data for the ortho-para conversion of H2 at 77 k rear earth metals (REM) and their Cu alloy films are given. Conversion on the surface of Sc, Y, La, Yb and Lu has been shown previously to follow a chemical mechanism, for the others it is magnetic. When alloyed with Cu, the specific catalytic activity (Ksp) of Sc, Y, La, Yb and Lu sharply increases. A sharp increase of Ksp is also observed on Cu alloys of Ce, Sm, Nd, Pr, Eu and Gd and the chemical conversion mechanism becomes predominant. On Tb, Dy, Er, Ho and Tm, Ksp rises only slightly and the magnetic mechanism preserves.