High-throughput synthesis and screening of catalytic materials. Case study on the search for a low-temperature catalyst for the oxidation of low-concentration propane.

Low-temperature catalysts for the total combustion of low-concentration propane in air have been searched for applying a combinatorial approach including an optimization procedure based on a genetic algorithm. A 1st generation of catalysts was prepared by impregnation of TiO2 and Fe2O3 materials with randomly mixed solutions of eight individual compounds (H2[PtCl6]·xH2O, (NH4)2PdCl6, RhCl3·2H2O, RuCl3·H2O, H[AuCl4]·3H2O, Ag lactate, Cu(NO3)2, Mn(NO3)2) considered as potential catalytic compounds. After parallel testing of the 1st generation of the catalytic materials applying high-throughput testing equipment the most active catalysts were chosen to create a 2nd and after its testing a 3rd generation, respectively. A genetic algorithm was applied to set the compositions of the catalytic compounds of the 2nd and 3rd generation. Fe2O3 was not used as support for the succeeding generations since it lead to significantly inferior catalytic performances than TiO2. The optimization strategy led to improved catalysts. Most of the final material converted propane to CO2 at 150°C, the best ones oxidized propane even at 50°C. Furthermore, the goal was pursued to compare the performance of two different high-throughput testing equipments. In both cases the ranking of 45 catalysts was nearly the same