SIZE-CONTROLLABLE TRANSITION METAL CLUSTERS IN MCM-41 FOR IMPROVING CHEMICAL CATALYSTS

摘要

Metal-substituted mesoporous oxide frameworks, such as Co-MCM-41, with different pore diameters are disclosed, which are resistant to thermal reduction. The reducibility correlates strongly with the pore radius of curvature, with the cobalt incorporated in smaller pores more resistant to complete reduction. The reducibility also correlates with the pH level of the solution used to prepare the framework. Other oxide substrates, such as Al₂O₃, and other transition metal ions in addition to or instead of Co can be employed. The metal-ion substituted oxide framework substantially improves metal catalysis and in a large number of catalytic processes, e.g., to remove unwanted chemicals such as sulfur or nitrogen from petroleum products, for selective hydrogenation of organic chemicals, in ammonia synthesis, and as automotive exhaust catalyst.