Pt/K–βAl2O3 solid electrolyte cell as a “smart electrochemical catalyst” for the effective removal of NOx under wet reaction conditions

This study has shown that the phenomenon of electrochemical promotion can be used to activate a metal catalyst for the selective catalytic reduction of nitrogen oxides (NOx) in the presence of water in the feed. The application of different potentials optimized the catalytic performance of the Pt catalyst-working electrode at each reaction temperature range. In addition, the measurement of the open circuit voltage in the cell gave useful information on the competitive adsorption between the reactants. Thus, very interestingly, the combined use of the Pt/K–βAl2O3 cell as a sensor and as an electrochemical catalyst allows anticipating and optimizing the catalytic behaviour of the system under changing reaction conditions, such as those found in the exhaust of an engine. Finally, characterization of the cell by Cyclic Voltammetry along with NOx analysis and XRD provided useful information about the nature of the promoter species under wet reaction conditions.