Selective reduction of NOx by hydrogen and methane in natural gas stationary sources over alumina-supported Pd, Co and Co/Pd catalysts: Part A. On the effect of palladium precursors and catalyst pre-treatment

The aim of the present work is to study the selective reduction of NOx from natural gas sources. The unburned methane can be used as reductant. Another reductant such as hydrogen can be created in situ, using a microreformer. The results suggest that the NOx are reduced by H2 at low temperature, when methane is not activated and at higher temperature the methane is then the main reductant. However, the catalytic behaviour depends on the metal precursor and the catalyst treatment. The most prominent result is obtained on the palladium catalyst prepared from Pd(NH3)4(NO3)2 precursor. Comparing the reduction and the calcination step in the course of catalyst preparation, one can conclude that calcination lead to the higher activity in deNOx, since reduced catalysts are oxidized during the deNOx process.