A considerable sintering of disperse Pt-black samples was observed earlier in the of hydrogen presence at temperatures well belowthe melting point (450—500 K). This effect of hydrogen was studied ona highly disperse and low ordered Pt-black sample by in situ X-ray diffraction measurements of the crystallite size and latt ce distortionduring temperature-programmed treatments. At room temperature the lattice strain decreased showing that the hydrogen strongly decreased the energy barrier conserving the crystal faults. This was not accompanied by a significant crystallite growth. At 500—600 K the fast decrease of lattice strain and a concomitant crystallite growth was found. It is thought that both the room and the higher temperature phenomenon can be related to the formation of a two-component quasi-liquid mixture of Pt and the absorbed hydrogen in the dislocations or that of the adsorbed hydrogen on the surface, respectively.
- Effect of hydrogen
ASJC Scopus subject areas
- Physical and Theoretical Chemistry