A comparison between electrochemical and conventional catalyst promotion: The case of N2O reduction by alkanes or alkenes over K-modified Pd catalysts

Pekridis, G.; Kaklidis, N.; Konsolakis, Michalis; Athanasiou, C.; Yentekakis, I.V.; Marnellos, George

doi:10.1016/j.ssi.2010.03.024

Cited by 13 publications

(21 citation statements)

References 32 publications

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“…In addition, the propene conversion (data not shown for brevity) is suppressed by potassium, indicating an inhibiting effect of K on hydrocarbon activation, as will be discussed later. A similar behavior has been observed both for N 2 O and hydrocarbon conversion under oxygen excess conditions when alkanes were employed as reducing agents [11].…”

Section: Xps Analysissupporting

confidence: 76%

“…The resulting material was initially dried at 120°C for 2 h, followed by calcination at 600°C for 6 h. Following that potassium (K) promoted catalysts were synthesized by subsequent impregnation of the Pd/Al 2 O 3 catalyst in a KOH solution with the desired concentration to yield K-loadings between 0 and 9 wt%, as indicated by a previous study [11]. The resulting materials were initially dried at 120°C for 2 h, followed by calcination at 600°C for 4 h. The as prepared samples were designated as KX, where X denotes the K-loading.…”

Section: Methodsmentioning

confidence: 99%

“…In the present work, motivated by the enhanced de-N 2 O activity of Pd/Al 2 O 3 catalysts as well as the significant modifications that can be induced by electropositive promoters on Pd surface chemistry [11], we focus on the effect of potassium (K) promoter on N 2 O reduction by hydrocarbons over Pd/Al 2 O 3 catalysts. Particular emphasis is given on the effect of the promoter on the surface properties of Pd catalysts, as revealed by different characterization techniques (X ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)-CO adsorption, FTIR-pyridine adsorption), in order to directly correlate the surface behavior of K-promoted catalysts with their catalytic performance.…”

Section: Introductionmentioning

confidence: 99%

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Correlation of Surface Characteristics with Catalytic Performance of Potassium Promoted Pd/Al2O3 Catalysts: The Case of N2O Reduction by Alkanes or Alkenes

et al. 2011

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The present study aims at investigating the role of potassium (K) promoter on the surface and catalytic behavior of Pd/Al 2 O 3 catalysts during N 2 O reduction by alkanes (CH 4 , C 3 H 8 ) or alkenes (C 3 H 6 ). In this context, the surface properties of un-promoted and K-promoted catalysts were evaluated by means of X ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of CO adsorption and FTIR-pyridine adsorption. The results reveal that both the electronic and structural properties of Pd entities can be substantially modified by potassium ions, which are in close proximity with catalyst surface without exhibiting a tendency to accumulate. This in turn results in significant modifications on reactants/intermediates chemisorption bonds, affecting the catalytic performance of K-promoted catalysts. Indeed, it was found that potassium strongly promotes the N 2 O reduction by propane or propene yielding notably lower N 2 O light off temperatures (ca. 100°C) as compared to those obtained over un-promoted catalysts. On the contrary, a slight inhibition upon K-promotion was observed, when using CH 4 as reducing agent, implying that the action of the K-promoter is strongly related with the reducing agent used and its' relative interaction with the catalyst's surface. The results are discussed in terms of the correlation between the surface chemistry modifications induced by electropositive promoters and the de-N 2 O performance of K-promoted catalysts.

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Section: Xps Analysissupporting

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Correlation of Surface Characteristics with Catalytic Performance of Potassium Promoted Pd/Al2O3 Catalysts: The Case of N2O Reduction by Alkanes or Alkenes

et al. 2011

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“…Under this view, it has been demonstrated that the addition of Li, Na K, Cs or Sr on Rh/Al 2 O 3 catalyst, increased the efficiency of the catalyst for the nitrous oxide abatement [13,21]. In addition, K-modification (either electrochemically or conventionally) on Pd/Al 2 O 3 catalysts enhanced the N 2 O decomposition in the presence of hydrocarbons [11,13,22].…”

Section: Introductionmentioning

confidence: 99%

Effect of Alkali Promoters (K) on Nitrous Oxide Abatement Over Ir/Al2O3 Catalysts

Papista

Pachatouridou

Goula³

et al. 2016

Top Catal

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The promoting impact of potassium (0-1 wt% K) on nitrous oxide (N 2 O) catalytic decomposition over Ir/ Al 2 O 3 is investigated under both oxygen deficient and oxygen excess conditions. All samples were characterized by means of X-ray powder diffraction (XRD), temperatureprogrammed reduction (H 2 -TPR), ammonia desorption (NH 3 -TPD) and Fourier Transform Infrared Spectroscopy of pyridine adsorption (FTIR-Pyridine). The results reveal that the K-free Ir/Al 2 O 3 catalyst consists mainly of the IrO 2 phase, exhibiting also significant Lewis acidity, which is gradually eliminated by the addition of K. Catalytic performance results showed that the deN 2 O performance in the absence of O 2 in the feed mixture is negatively affected upon increasing potassium loading. However, under oxygen excess conditions, a pronounced effect of K is observed. Although the catalytic performance of the undoped catalyst is drastically hindered by the presence of O 2 , the K-promotion notably prohibits the oxygen poisoning. The optimum deN 2 O performance under oxygen excess conditions is obtained with potassium loading of 0.5 wt% K, which offers complete conversion of N 2 O at 580°C, instead of the corresponding 50 % N 2 O conversion achieved with the un-modified sample. On the basis of characterization results, it was concluded that alkali-doping in combination with oxygen excess conditions are required towards the formation of active Ir entities.

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“…Because of the active chemical properties, alkali metals are widely used in the catalytic reaction [10][11][12] . Salinas et al 10 prepared potassium-supported TiO2 catalysts for transesterification reaction.…”

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confidence: 99%

A Convenient Method to Prepare Novel Alkali Metal Potassium Doped Carbon Nitride Photocatalyst with Tunable Band Structure

Zhao¹,

Zhang²,

Wang³

2014

Asian J. Chem.

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Nowadays, energy and environmental crisis are the great problems for all the countries in the world. With outstanding virtues, including non-pollution and inexhaustible supply, solar light is considered as one of the most promising candidate to resolve the energy crisis and environmental problems. However, low energy conversion efficiency still restricts its practical application. Recently, a metal-free visible-light photocatalyst graphitic carbon nitride (g-C 3 N 4) has attracted intensive interest for its many promising applications. The g-C 3 N 4 has a moderate band gap (2.7 eV), high chemical and thermal stability as well as fascinating electronic property. However, the rapid photogenerated electron-hole pair recombination leads to the low activity in practical applications 1,2. Several routes have been developed to solve this problem 3-6 , preparation of porous 7 g-C 3 N 4 , protonating by strong acids 8 and designing composite with other semiconductors 9. Among those strategies, doping is one of the most convenient and effective method. Yan et al. 3 prepared B doped g-C 3 N 4 and suggested that the enhanced degradation performance of Rhodamine-B was due to the improvement of dye adsorption and light absorption ability. Zhang et al. 4 synthesized phosphorus doped g-C 3 N 4 using ionic liquid [Bmim]PF 6 as phosphorus source. The obtained material exhibited significantly improved electrical conductivity and photocurrent. Noble metal, such as Pt, Pd and Ag, is an effective dopant to trap the

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A comparison between electrochemical and conventional catalyst promotion: The case of N2O reduction by alkanes or alkenes over K-modified Pd catalysts

Cited by 13 publications

References 32 publications

Correlation of Surface Characteristics with Catalytic Performance of Potassium Promoted Pd/Al2O3 Catalysts: The Case of N2O Reduction by Alkanes or Alkenes

Correlation of Surface Characteristics with Catalytic Performance of Potassium Promoted Pd/Al2O3 Catalysts: The Case of N2O Reduction by Alkanes or Alkenes

Effect of Alkali Promoters (K) on Nitrous Oxide Abatement Over Ir/Al2O3 Catalysts

A Convenient Method to Prepare Novel Alkali Metal Potassium Doped Carbon Nitride Photocatalyst with Tunable Band Structure

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