NOx storage capacity of yttria-stabilized zirconia-based catalysts

Investigations of soot combustion on yttria-stabilized zirconia by environmental transmission electron microscopy (ETEM)

“…We have recently investigated the catalytic properties of yttriastabilized zirconia (YSZ) [3,5,9]. Zirconia alone already presents a catalytic effect for soot oxidation.…”

“…The high exhaust gas temperatures required for regeneration are achieved via postinjections of fuel, allowing the production of extra heat in the diesel oxidation catalyst (DOC) placed upstream the DPF and therefore of higher temperature in the exhaust [2], enhanced by oxidants present in the flow (O 2 and NO 2 ). The evolution of Euro standards includes an abatement of NO x emissions [3], requesting the development of DPF promoting O 2 oxidation. Numerous catalysts for promoting the oxidation of soot by O 2 have been investigated: Labased perovskites and ceria-based oxides are extensively studied along with transition metals (Cu, V, Mo, Co, and Fe) and/or potassium supported on different materials, such as CeO 2 , ZrO 2 , or Al 2 O 3 [4][5][6][7].…”

Activation of Porous Pt Electrodes Deposited on YSZ Electrolyte by Nitric Acid Treatment

“…High capacity of YSZ to adsorb NO x species (NO x stands for NO and NO 2 ) was reported in [ 13 , 14 ]. It was assumed that the interaction of NO x on YSZ surface happens with the participation of oxygen vacancies in the electrolyte, which provide NO x adsorption sites.…”

“…In accordance with the reactions (1,2), the impregnation of the porous Pt electrode with nitric acid followed by annealing at 800 °C results in the formation of nitric oxide, which can adsorb on the surfaces of the electrode and the electrolyte. As it was shown in [ 13 , 14 ], YSZ possesses high capacity to adsorb nitrogen oxides due to the presence of oxygen vacancies which act as adsorption sites. Formation of the bridged nitrate species on YSZ surface due to the strong interaction of NO with YSZ should facilitate the dissociative adsorption and surface diffusion of oxygen.…”

“…It was assumed that the adsorbed NO species promoted the dissociative adsorption of molecular oxygen and transport of oxygen atoms to the TPB region (TPB is a triple phase boundary between the solid electrolyte, electrode, and gas). High capacity of YSZ to adsorb NO x (NO x stands for NO and NO 2 ) species was revealed and explained by participation of oxygen vacancies in the electrolyte which provide NO x adsorption sites [ 13 , 14 ]. It is reasonable to expect that the adsorbed NO x species should affect the oxygen exchange rate at a YSZ/electrode interface.…”