NOx decomposition by electrochemical reactor with electrochemically assembled multilayer electrode

Optimization of an electrochemical cell with an adsorption layer for NOx removal

“…Although on a cell without the adsorption layer, the deposition of a YSZ upper layer led to improve NO x selectivity [8,12,13], after adding the adsorption layer, we believe the presence of the YSZ cover layer will be harmful to NO x decomposition.…”

“…According to systematic research [8,[12][13][14][15] on the NiO|YSZ catalytic layer by Bredikhin and colleagues, it is believed that there are two reaction sites for NO and O 2 molecules in the catalytic layer. As schematically shown in figure 6, one is the F-center near the three phase boundaries of YSZ|Pt|gas or YSZ|Ni|gas, which is dominated by O 2 reduction in O 2 -rich environment.…”

“…During the cell operation, the external voltage was applied between the mesh-patterned Pt cathode and the Pt|YSZ (yttria stabilized zirconia) anode, which led to the polarization of the YSZ electrolyte and the reduction of NiO to nano Ni grains in the vicinity of NiO|YSZ interfacial regions in the catalytic layer [8,9,[12][13][14][15]. Because the adsorption and decomposition of NO x molecules occurs in preference to oxygen molecules on Ni grain surfaces [16][17][18][19], the self-assembled nano-pores and nano-Ni particles in the catalytic layer provide a highly selective reaction site for NO x reduction [8,9,[12][13][14][15] and also suppress the unwanted reaction of oxygen 3 decomposition [20,21]. The adsorption layer, coated on the cathode side of the electrochemical cell, was made of a traditional NSR (NO x storage and reduction) catalyst that is normally used to trap and reduce NO x through a cyclic switch between lean and rich conditions [22].…”

“…It was previously proposed [9] that an additional adsorption layer could provide a NO x -rich atmosphere to the reaction sites in the NiO|YSZ catalytic layer to promote NO x reduction. A YSZ cover layer was deposited on the top of the catalytic layer in order to increase the NO x selectivity, because it was stated that the YSZ upper layer led to inhibit the O 2 decomposition on the open surface of the catalytic layer and increase the amount of nano-Ni grains in the interface region of YSZ|NiO [8,12,13].…”

Electrochemical reduction of O2 and NO on Ni, Pt and Au

“…It has been found that only a few electrode materials have a higher activity towards the reduction of nitric oxide than towards the reduction of oxygen. Ni has been proposed as a cathode for the electrochemical reduction of NO x in a net oxidising atmosphere [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Ni exhibits some selectivity towards the reduction of nitric oxide in a net oxidising atmosphere.…”