Catalytic consequences of reactive oxygen species during C3H6 oxidation on Ag clusters

Lachkov, Petar T.; Chin, Ya-Huei Cathy

doi:10.1016/j.jcat.2018.07.011

Cited by 12 publications

(12 citation statements)

References 49 publications

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“…We should mention selective oxidation toward acrolein originates from C–H activation, which could be catalyzed by lattice oxygen of transition metal oxides, and propene epoxide (PO) formation is the most desirable yet challenging for transition metal oxide catalysts; hence, we only present and discuss these two reaction routes (epoxidation and allylic oxidation) over CrO x /γ-Al 2 O 3 catalysts. Whereas other side products, like acetone, propanal, and CO 2 , as previous reported on other catalysts, − are not shown and discussed in detail for the simplicity of this work.…”

Section: Resultsmentioning

confidence: 71%

“…To the best of our knowledge, CrO x catalysts, a transition metal oxide, have been scarcely used for selective oxidation of propene, despite being known as active in catalyzing polymerization, dehydrogenation, and oxidative dehydrogenation of alkanes . One of the most highly challenging research projects in heterogeneous catalysis is epoxidation of propene when using oxygen as the oxidant. − Lambert et al have theoretically implied the lower basicity of oxygen species of copper catalysts facilitates the formation of reaction intermediates for achieving superior propene oxide (PO) selectivity. Thus, the lower basicity oxygen species have, the more electrophilic oxygen species are, the higher PO selectivity is; otherwise, the reaction proceeds toward allylic oxidation or complete combustion.…”

Section: Introductionmentioning

confidence: 99%

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Crystal-Facet Modulated CrO_x/γ-Al₂O₃: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene

Wang

et al. 2020

Langmuir

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The crystal-facet effect of catalytic supports plays a crucial role in tailoring the physicochemical properties of active sites and the surface chemically bonded polymer can also regulate the local environment around active sites for optimizing catalytic performance. Herein, we report the effect of exposed facets of γ-Al2O3 supports and further modification by surface bonded long-chain polydimethylsiloxane (PDMS) on the properties of CrO x /γ-Al2O3 catalysts for selective oxidation of propene. The {111} facets of γ-Al2O3 stabilize “non-redox Cr3 +” and promote the overall oxidation rates compared with catalysts on {110} facets of γ-Al2O3. The surface bonded PDMS, with grafting density being about 0.13 chains/nm2, endows a hydrophobic environment to facilitate the enrichment of the hydrophobic substrate and the desorption of hydrophilic products and occupies some acid sites on catalysts to limit acid-catalyzed side reactions. The inherent liquidlike nature of bonded PDMS also forms a setting that can regulate the redox ability of surface Cr species, that lead to modified activation of oxygen toward more surface adsorbed species. As a result, the modified catalysts enhance the whole oxidation process with favorable formation of epoxide product at low reaction temperatures (<225 °C). Our findings highlight the impact of surface chemically bound polydimethylsiloxane (PDMS) upon tailoring the surroundings of the catalyst surface, and that combined with facet-effect of supports can tune the reaction process toward selective ones.

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Section: Resultsmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Crystal-Facet Modulated CrO_x/γ-Al₂O₃: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene

Wang

et al. 2020

Langmuir

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“…Two models-pseudo-first-order and pseudo-second-order-were used to investigate the degradation kinetics of azophloxine degradation by the FeAlg-ACFs/PMS system. The pseudo-first-order model was first described by Lagergren (1898) and can be generally expressed as follows: log (q e − q t ) = log q e − k 1 t/2.303 (10) where q t is the amount of azophloxine removed at time t (min) and k 1 is the equilibrium rate constant (min −1 ). The values of log(q e − q t ) are linearly related with t, while k 1 and q e can be determined from the slope and intercept of the plot of log(q e − q t ) versus t, respectively.…”

Section: Reaction Kinetics Of Catalytic Oxidation By the Fealg-acf/pms Systemmentioning

confidence: 99%

“…Among many water pollution treatment methods, Fenton-like oxidation technology, as a typical advanced oxidation technology, has been widely favored by researchers due to its advantages of high efficiency, environmental friendliness, and circularity [5][6][7][8][9]. The amount of reactive oxygen species (ROS) is an important factor for the catalytic efficiency of the photocatalytic system, especially in relatively mild conditions [10][11][12][13]. Peroxymonosulfate (PMS) is a widely used material to provide ROS to remove a variety of refractory organic pollutants in environmental remediation [14,15].…”

Section: Introductionmentioning

confidence: 99%

Rapid Removal of Azophloxine via Catalytic Degradation by a Novel Heterogeneous Catalyst under Visible Light

Xia

Fang

et al. 2020

Catalysts

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Azo dyes are the most widely used synthetic dyes in the printing and dyeing process. However, the discharge of untreated azo dyes poses a potential threat to aqueous ecosystems and human health. Herein, we fabricated a novel heterogeneous catalyst: activated-carbon-fiber-supported ferric alginate (FeAlg-ACF). Together with peroxymonosulfate (PMS) and visible light, this photocatalytic oxidation system was used to remove an azo dye—azophloxine. The results indicated that the proposed catalytic oxidation system can remove 100% of azophloxine within 24 min, while under the same system, the removal rates were only 92% and 84% when ferric alginate was replaced with ferric citrate and ferric oxalate, respectively, which showed the superiority of FeAlg-ACF. The degradation of azophloxine is achieved by the active radicals (SO4•− and •OH) released from PMS and persistent free radicals from activated carbon fiber. Moreover, due to ferric alginate’s highly intrinsic photosensitivity, visible radiation can further enhance the ligand-to-metal charge transfer (LMCT) processes. After 24 min of treatment, the total organic carbon of the azophloxine solution (50 μmol/L) decreased from 1.82 mg/L to 79.3 μg/L and the concentration of nitrate ions increased from 0.3 mg/L to 8.6 mg/L. That is, up to 93.5% of azophloxine molecules were completely degraded into inorganic compounds. Consequently, potential secondary contamination by intermediate organic products during catalytic degradation was prohibited. The azophloxine removal ratio was kept almost constant after seven cycles, indicating the recyclability and longevity of this system. Furthermore, the azophloxine removal was still promising at high concentrations of Cl−, HCO3−, and CO32−. Therefore, our proposed system is potentially effective at removing dye pollutants from seawater. It provides a feasible method for the development of efficient and environmentally friendly PMS activation technology combined with FeAlg-ACF, which has significant academic and application value.

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“…  (10) where qt is the amount of azophloxine removed at a time t (min) and k1 is the equilibrium rate constant (min -1 ). The values of log (qe -qt) are linearly with t, while k1 and qe can be determined from the slope and intercept of the plot of log (qe -qt) versus t, respectively.…”

Section: Reaction Kinetics Of Catalytic Oxidation By Fealg-acf/pms Symentioning

confidence: 99%

Rapid Removal of Azophloxine via Catalytic Degradation by A Novel Heterogeneous Catalyst under Visible Light

Wu¹,

Xia²,

Fang³

et al. 2020

Preprint

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Azo dyes are the most widely used synthetic dyes in the printing and dyeing process. However, the discharge of untreated azo dyes poses potential threat for human health and aqueous ecosystem. Herein, we fabricated a novel heterogenous catalyst - activated carbon fiber-supported ferric alginate (FeAlg-ACF) . Together with peroxymonosulfate (PMS) and visible light, this photocatalytic oxidation system was used to remove an azo dye - azophloxine. The results indicated that the proposed catalytic oxidation system can remove 100% azophloxine within 24 min, while under the same system, the removal rate was only 92 % and 84 % when ferric alginate was replaced with ferric citrate and ferric oxalate respectively, which showed the superiority of activated carbon fiber-supported ferric alginate. The degradation of azophloxine is achieved by the active radicals (SO4•− and •OH) released from PMS and persistent free radicals from activated carbon fiber. After treating for 24 min, the total organic carbon of azophloxine solution (50 μmol/L) decreased from 1.82 mg/L to 79.3 μg/L and the nitrate concentration of ions increased from 0.3 mg/L to 8.6 mg/L. That is, up to 93.5% azophloxine molecules were completely degraded into inorganic compounds. Consequently, potential secondary contamination by intermediate organic products during catalytic degradation was prohibited. The azophloxine removal ratio was kept almost constant after seven cycles, indicating the recyclability and longevity of this system. Furthermore, the azophloxine removal was still promising at high concentrations of Cl-, HCO3-, CO32-. Therefore, our proposed system is potentially effective to remove dye pollutants from seawater. It provides a feasible method for the development of efficient and environmental friendly PMS activation technology combined with FeAlg-ACF, has significant academic and application value.

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Catalytic consequences of reactive oxygen species during C3H6 oxidation on Ag clusters

Cited by 12 publications

References 49 publications

Crystal-Facet Modulated CrO_x/γ-Al₂O₃: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene

Crystal-Facet Modulated CrO_x/γ-Al₂O₃: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene

Rapid Removal of Azophloxine via Catalytic Degradation by a Novel Heterogeneous Catalyst under Visible Light

Rapid Removal of Azophloxine via Catalytic Degradation by A Novel Heterogeneous Catalyst under Visible Light

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Catalytic consequences of reactive oxygen species during C3H6 oxidation on Ag clusters

Cited by 12 publications

References 49 publications

Crystal-Facet Modulated CrOx/γ-Al2O3: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene

Crystal-Facet Modulated CrOx/γ-Al2O3: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene

Rapid Removal of Azophloxine via Catalytic Degradation by a Novel Heterogeneous Catalyst under Visible Light

Rapid Removal of Azophloxine via Catalytic Degradation by A Novel Heterogeneous Catalyst under Visible Light

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Crystal-Facet Modulated CrO_x/γ-Al₂O₃: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene

Crystal-Facet Modulated CrO_x/γ-Al₂O₃: Quasi-Liquid Surface Modification by Bonded Polydimethylsiloxane for Catalytic Oxidation of Propene