Studies of the combinatorial synthesis of catalyst oxide powders

In recent years, combinatorial synthesis has become a promising tool for the discovery of novel advanced materials. In this research a protocol for the combinatorial synthesis of mixed and complex oxide catalysts was developed. Using solution deposition, libraries of materials were first generated with the Drop Deposit Method, then with the Support Pellet Impregnation Method. Neither of these methods met the criteria for a feasible protocol to generate combinatorial libraries of catalysts: (1) the preparation method must be a high-throughput technique; (2) the process must produce active catalyst compositions in a known system; and (3) the protocol must be easily applied to very different chemical systems.; The third technique used in this research was a Polymerizable-Complex Powder processing method, in which metal ions are evenly dispersed throughout a polymer resin that can decompose to form a homogeneous oxide powder. This process provided a viable protocol for the development of combinatorial oxide powder catalyst libraries. The Cu_1−xCe _xO₃ and La_1−xSr _xCoO_3−δ systems were examined for their catalytic activity in the carbon monoxide oxidation reaction. Each system showed catalytic activity in the predicted region (200 to 320°C) and had similar powder properties among different samples of the same chemical system.; Following the development of the protocol—which included generating libraries with a polymerizable-complex method, decomposing the polymer resins to oxide powders, then examining the samples for catalytic activity—the process was applied to ternary systems. Several libraries modelled on the LaCoO₃ system were produced, and the best catalytic activity for the CO oxidation reaction was shown by the La_xSr _yCo_zO system, and two distinct regions of active compositions could be observed: high Co content (active between 170 and 215°C) and La_0.5Sr_0.5CoO₃ region (240 and 320°C).; Finally, the protocol was applied to the combustion of soot, modelling diesel exhaust filter regeneration. Libraries of mixed transition metal oxides and alkali metal oxides were generated and coated with a simulated soot solution. These were then examined in the catalytic reactor with oxygen and nitrogen flowing. Some compositions showed activity, but the temperature increase observed with IR thermography was smaller than expected.