Verfahren zur Reduktion von NOx aus Abgasen

摘要

A process is disclosed for reducing Nox in which x equals 1 or 2, from exhaust fumes on heterogeneous catalysts with hydrocarbons, carbon monoxide, hydrogen or their mixtures, in the presence of oxygen, at a temperature from 100 to 650 DEG C and an absolute pressure of 0.5 to 50 bars. As heterogeneous catalysts, bimodal or higher-modal compounds are used which have the general formula (I) A1-x M2 O4 and are optionally doped with rare earths, precious metals, titanium, vanadium, molybdenum, tungsten or their mixtures. In the formula (I), A stands for magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin or their mixtures; M stands for aluminium, gallium, indium, tin, chromium, manganese, iron, cobalt, nickel, copper, zinc or their mixtures; and x equals 0 to 0.99. The oxygen atoms of said compounds are arranged in the densest possible cubic sphere packing in which A is located in the tetrahedral gaps and M in the octahedral gaps, wherein A may also occupy octahedral gaps when an equivalent amount of M occupies tetrahedral gaps.