A new improvement of catalysis by solid-state electrochemistry: An electrochemically assisted NOx storage/reduction catalyst

In this paper, we report a novel electrochemically assisted NOx storage/reduction catalyst (Pt–KβAl2O3) that can operate over a range of reaction conditions for the effective removal of NOx. Under negative polarization, NOx was stored on the catalyst surface in form of potassium nitrates. Under positive polarization, the catalyst was regenerated, and the stored nitrates were efficiently desorbed and reduced to N2. The variation of the current under the applied polarizations allowed monitoring the progress of both the storing and the regeneration phases, and thus optimisation of the duration of both sequences in a technically feasible manner. In addition, the possibility of electrochemical regeneration of the catalyst surface allowed work under a fixed lean gas composition, which implies an important technological advance for the NSR process. The electrochemically assisted NOx storage/reduction experiments were supported by NOx-TPD and cyclic voltammetry measurements, which also revealed useful information about the chemisorption properties of the electrochemical catalyst.