HREM STUDIES OF LAYERED TRANSITION-METAL SULFIDE CATALYTIC MATERIALS

Recent studies using HREM techniques are yielding new insight into the nature of the layered transition metal sulfide (LTMS) catalytic mater ials. While the insight being generated is still at an early stage, HR EM techniques are showing promise in solving complex problems in this field which have been studied for many years. HREM techniques are begi nning to elucidate the structure of the catalytically active 'edge' si tes and to reveal the atomic structure of these edge terminations. HRE M is also generating new insight into the problem of disorder in the l ayered TMS which has hindered understanding of these systems. Finally, HREM is yielding an insight into the very complex 'promotion' problem . Evidence is presented that the older idea of pseudo-intercalation re sulting in charge transfer and thus promotion may be correct.