H2dissociation over Ag/Al2O3: the first step in hydrogen assisted selective catalytic reduction of NOx

Klacar, Simon; Grönbeck, Henrik

doi:10.1039/c2cy20343j

Cited by 21 publications

(11 citation statements)

References 57 publications

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“…The reduction of Mn 4+ was enhanced by the presence of Ag, of which Ag 0 might facilitate the activation (dissociation) of hydrogen and spill over of hydrogen from Ag 0 to Mn 4+ and MnO x dispersion in AgMn/HZ might be better than that in Mn/HZ. 30,31 The calculated Mn 4+ /Mn 3+ atomic ratio (using the same sequential steps as mentioned above) for AgMn/HZ based on the TPR results was 2 : 1, which is also consistent with the XPS results.…”

Section: Tpr Analysissupporting

confidence: 80%

Ozone catalytic oxidation of adsorbed benzene over AgMn/HZSM-5 catalysts at room temperature

Yang

Shi

et al. 2014

Catal. Sci. Technol.

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Section: Tpr Analysissupporting

confidence: 80%

Ozone catalytic oxidation of adsorbed benzene over AgMn/HZSM-5 catalysts at room temperature

Yang

Shi

et al. 2014

Catal. Sci. Technol.

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“…Higher reduction temperatures may facilitate the loss of CUSs (i.e. Lewis acid sites) by removing them via heterolytic cleavage of H 2 [44,45], as shown by the decrease in values of N ACID with increasing reduction temperatures (Table 1). Furthermore, previous reports have demonstrated that the key CUSs in molybdenum sulfide catalysts, which are similar in surface properties to phosphide catalysts (i.e.…”

Section: Mechanistic Evaluationmentioning

confidence: 99%

Investigating the multifunctional nature of bimetallic FeMoP catalysts using dehydration and hydrogenolysis reactions

Rensel

Kim

Bonita

et al. 2016

Applied Catalysis A: General

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Herein, we investigate the effects of altering the multifunctional nature of a series of FeMoP catalysts for biomass deoxygenation reactions. Unsupported FeMoP catalysts were synthesized at reduction temperatures between 650 °C and 850 °C. The reduction temperature used during the synthesis of FeMoP altered the surface properties of these materials (i.e., acidity and CO-titrated metal sites) while leaving the bulk crystal structure of FeMoP unaffected. This alteration in the surface properties significantly affected the catalytic performance of FeMoP materials in the deoxygenation reactions. The catalytic performance of the FeMoP catalysts was first investigated using the acid catalyzed, non-aqueous, dehydration of cyclohexanol. Aside from showing high selectivities to cyclohexene (> 99 %) for all catalysts, the experiments demonstrated that FeMoP-650 showed the highest initial rate due to the largest number of surface acid sites among these catalysts. In addition, these FeMoP catalysts were examined using the hydrodeoxygenation (HDO) of phenol. While all FeMoP catalysts were highly selective to benzene (~ 90 %) at conversions less than 10 %, studies at higher conversions of phenol provided evidence that catalysts with a higher amount of acid sites maintained enhanced selectivity to benzene. Furthermore, the stability of FeMoP catalysts for phenol HDO was tested with a 48-hour time-on-stream (TOS) study. FeMoP exhibited excellent stability, as evidenced by the retention of the initial reaction rate, selectivity to benzene, and oxidation state of surface species throughout the TOS run.

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“…Ag shows the lowest reactivity toward H 2 ;16–18 its dissociation features large activation barriers even at low‐coordinated surface sites 19. Nevertheless, Sárkány and Révay studied the hydrogenation of ethyne over SiO 2 ‐ and TiO 2 ‐supported Ag nanoparticles (4–8 nm) and reported full selectivity to ethene at a low degree of ethyne conversion (3–13 %) 20.…”

Section: Introductionmentioning

confidence: 99%

Silver Nanoparticles for Olefin Production: New Insights into the Mechanistic Description of Propyne Hydrogenation

et al. 2013

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The gas‐phase partial hydrogenation of propyne was investigated over supported Ag nanoparticles (2–20 nm in diameter) prepared by using different deposition methods, activation conditions, loadings, and carriers. The excellent selectivities to propene attained over the catalysts, exceeding 90 %, are independent of the particle size but the activity is maximal over approximately 4.5 nm Ag particles. Certain kinetic fingerprints of Ag, such as the positive dependence on the alkyne pressure, the relatively low reaction order in H2, and the low apparent activation energy, deviate from those of conventional hydrogenation metals such as Pd and Ni, questioning the applicability of the classical Horiuti–Polanyi scheme. Periodic dispersion‐corrected density functional theory (DFT‐D) calculations and microkinetic analysis demonstrate the occurrence of an associative mechanism, which features the activation of H2 on the adsorbed propyne at structural step sites. By using the atomistic Wulff model, the number of B5 sites available on the Ag nanoparticles was estimated to be maximal in the size range of 3.5–4.7 nm. The rate of propene production correlates with the density of B5 sites, which suggests that the latter are potential active centers for the reaction. This alternative pathway broadens the mechanistic diversity of hydrogenation reactions over metal surfaces and opens new directions for understanding metals that do not readily activate H2.

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H₂dissociation over Ag/Al₂O₃: the first step in hydrogen assisted selective catalytic reduction of NO_x

Cited by 21 publications

References 57 publications

Ozone catalytic oxidation of adsorbed benzene over AgMn/HZSM-5 catalysts at room temperature

Ozone catalytic oxidation of adsorbed benzene over AgMn/HZSM-5 catalysts at room temperature

Investigating the multifunctional nature of bimetallic FeMoP catalysts using dehydration and hydrogenolysis reactions

Silver Nanoparticles for Olefin Production: New Insights into the Mechanistic Description of Propyne Hydrogenation

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