Electrochemical promotion of NO reduction by C3H6 and CO on Rh/YSZ catalyst — Electrodes

Pliangos, C.; Raptis, Constantine A.; Badas, Th.; Vayenas, C.G.

doi:10.1007/bf02375555

Cited by 22 publications

(32 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, there is not significant enhancement of N2 selectivity. When using propene [22], a positive current increases the NO conversion from 10 to 27 %, at 380 ~ in a reactant mixture close to the stoichiometry (1200 ppm C3H6, 950 ppm NO and 0.5 % 02). Simultaneously, the N2 selectivity slightly increases.…”

Section: Introductionmentioning

confidence: 92%

See 1 more Smart Citation

Electrochemical promotion of NO reduction by propene on Pt/YSZ

Beguin

Primet

Vernoux

et al. 2002

Ionics

View full text Add to dashboard Cite

International audienceThe reduction of NO by C₃H₆ in the presence of oxygen, is of great environmental importance. Platinum-based catalysts are very active but not selective towards N₂ production and mainly convert NO into N₂O, which participates to the greenhouse effect. Moreover, their operating temperature window is quite narrow. Electrochemical promotion was used to improve platinum catalytic behaviour. Platinum was deposited on YSZ (Y₂O₃ — stabilised ZrO₂), an O²-conductor. It was found that a negative current increased the rate of NO reduction and CO₂ formation. This rate enhancement was non-Faradaic with an apparent Faradaic efficiency (Λ) close to 180 indicating the manifestation of a NEMCA effect. However, the current application had no effect on the N₂ selectivit

show abstract

Section: Introductionmentioning

confidence: 92%

“…Pliangos and co-workers [22] have studied the electrochemical promotion of NO reduction on the Rh/YSZ system under a C3H6/NO/O 2 mixture, which was close to the stoichiometry. They tbund that the rates of CO2, N2 and N20 production are enhanced by both positive (dectrophobic behaviour) and negative (electrophilic behaviour) potentials or currents.…”

Section: 3mentioning

confidence: 98%

Electrochemical promotion of NO reduction by propene on Pt/YSZ

Beguin

Primet

Vernoux

et al. 2002

Ionics

View full text Add to dashboard Cite

show abstract

“…The observed increase in catalytic rate can be up to 5 orders of magnitude higher than the rate of ion transport to or from the solid electrolyte [1,2] and up to 150 times higher than the open-c~rcuit catalytic rate [3]. This phenomenon is known in the literature as Electrochemical Promotion or Non-Faradaic Electrochemical Modification of Catalytic Activity (NEMCA effect).…”

Section: Introductionmentioning

confidence: 97%

“…Recent studies [3,13] have shown that the NO reduction by C3H6 or CO in presence of 02 can be promoted electrochemically in a very pronounced manner on Rh films deposited on YSZ; A values between -300 and 400 and p values up to 150 have been measured as the reaction system was found to exhibit both electrophobic and electrophilic, i.e. inverted volcano, behavior [3,13].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electrochemical promotion of conventional and bipolar reactor configurations for NO reduction

Pliangos

Raptis

Bolzonella

et al. 2002

Ionics

Self Cite

View full text Add to dashboard Cite

Abstract. The reduction of NO by CO or C3H6 in the presence of 02, a reaction of great technological importance, was investigated on porous polycrystalline Rh catalyst films using a single-chamber and a wireless bipolar cell configuration. In the latter case the Rh catalyst films were deposited on the inner side of a YSZ tube, while two Au films deposited on the outer side of the tubes were used to polarize the Rh catalyst surface. The experimental conditions used in this study were close to those in the exhaust of a lean burn or diesel engine, i.e., high flowrates and space velocities and in some cases, considerable excess of oxygen. It was found that both direct (conventional) and indirect (wireless) polarization of the catalyst causes significant enhancement in the reaction rates (up to a factor of 20) and in the reactant conversion. These rate increases are strongly non-Faradaic with apparent Faradaic efficiencies, A, in the order of 100, manifesting the effect of Electrochemical Promotion or Non-faradaic Electrochemical Modification of Catalytic Activity (NEMCA).The Rh catalyst films were subsequently promoted in a classical way, via dry impregnation with NaOH, followed by drying and calcination. The thus Na-promoted Rh films were found to exhibit higher catalytic activity than the unpromoted films, with a considerable decrease in their light-off temperature. The effect of Electrochemical Promotion was then studied on these, already Na-promoted Rh catalysts. The results showed that the effect of Chemical and Electrochemical Promotion on the catalyst performance can be synergetic and their combination may lead to interesting practical applications. This is further supported by the fact that such bipolar tube configurations: (a) do not need electrical connection to the catalyst and (b) can be adapted easier to commercial exhaust units.

show abstract