Impedanzspektroskopie als Methode zur in situ-Reaktionsbeobachtung der DeNOx-SCR-Reaktion an Zeolithen und verwandten Materialien

This thesis discuss in situ reaction monitoring by means of impedance spectroscopy (IS). As a model reaction DeNOx-SCR at zeolites was chosen. This work is based on solvate supported proton transport mechanisms in zeolites. This conductivity could be measured in situ using impedance spectrsocopy. In a first step the descrimination of thermal desorption and catalytic conversion of ammonia over pure and metal-loaded zeolites was demonstrated by means of temperature as well as time depending IS. For detailed analysis a special-build measuring setup for simultaneous IS and DRIFTS was used. Additional to zeolites a porous zirconia-phosphate-based heterostructure was analyzed by means of IS in this thesis. It was shown that the general solvate-supported proton transport mechanisms could be transfered to this new class of materials. In a third part of this thesis the non-porous, semiconductiong material ammonia paratungstate (APT-4) was analyzed. For this material the thermal decomposition as well as the transformation of tungsten suboxide to tungsten oxide was monitored by in situ IS