(445c) Structure-Property Relationships Between Fractal Description of Pore Structure and Catalyst Effectiveness in the Ti-SBA-15 and V-SBA-15

Template-synthesized mesoporous silicates such as MCM- 41 and SBA-15 have proven popular as model supports for studies in heterogeneous catalysis; this is due to the generally facile synthesis, and well-characterized and uniform mesopore dimension is these materials. For SBA-15 the idealized nature of the pore structure is described as a dual micropore - mesopore system with a broad distribution of micropore sizes, alternatively the microporosity may be understood as a manifestation of the fractal nature of the mesopore surface. In this study, we use the fractal dimension of the surface - a quantifiable descriptor of mesopore surface character - to develop structure-property relationships in supported metal-oxide catalysis. SBA-15 synthesis conditions are modified to created different surface fractal dimension (or microporosity), the surface functionalized with titania, vandia, and other metal oxides. We use chemisorption, nitrogen physisorption SAXS, and spectroscopy to characterize the catalysts. We evaluate catalyst effectiveness in an appropriate test reaction, for example. methanol oxidation or alkene partial oxidation for vandia catalysts. We will show results illustrating the structure property relationship between surface fractal dimension and catalyst performance.