An attempt to bridge the pressure and material gap with a disperse model catalyst for low-temperature alkane reforming

Pt black was exposed to n-hexane/H-2 mixtures between 483 and 663 K followe d by O-2 and H-2 treatments at 603 K. XP and UP spectra were measured witho ut exposing the samples to air. 20-30% carbon accumulated after hydrocarbon exposures. O-2 removed most carbon. The surface C content increased after a subsequent contact with H-2, C 1s showing more "atomic carbon" as opposed to graphite after n-hexane exposure. Anisotropic recrystallization of Pt b lack favoring (220) and (311) lattice planes occurred under hydrogen-rich c onditions. Both findings were attributed to a H-2-induced solid-state rearr angement; H atoms penetrating into the crystal lattice, force subsurface ca rbon and oxygen atoms to the surface and a concomitant restructuring would occur. Thus another "hydrogen effect" has been recognized, leading to struc tures favorable for skeletal reactions of alkanes.