The effect of titanium dioxide doping on the surface reactivity of ruthenium-manganese bimetallic alloy

The SMSI effect on Ru:Mn bimetallic alloy system supported on high surface area TiO/sub 2/ and prepared by co-impregnation method was investigated. Two sets of samples with 20% Mn loading w/w were prepared on reduced at 723 deg. K (HTR) and other at 523 deg. K (LTR). The prepared supported system was characterized using SSIMS, TEM and selective chemisorption. The carbon monoxide hydrogenation was performed using a single pause flow reactor system. The hydrocarbon products were analyzed using a GC (Gas Chromatography). The analytical studies reveals the CO chemisorption decreases on the samples reduced at 723 deg. K. The SSIMS techniques indicates the presence of TiO/sub x/ species forming two new surface sites TiO/sub x/-Ru and TiO/sub x/-Mn. On TEM study these new species were found to be located at the immediate vicinity of metal particles. The increase in methanation activity and product selectivity on samples reduced at 723 deg. K as compared to the samples reduced at 523 deg. K were possibly caused due to the presence of these new surface sites. These new surface sites modify the surface geometry electronically. (author) 6 tabs.; 25 refs