Influence of Mn content on the catalytic properties of Cu-(Mn)-Zn-Mg-Al mixed oxides derived from LDH precursors in the total oxidation of methane

Răciulete, Monica; Layrac, Géraldine; Papa, Florica; Negrilă, Cătălin; Tichit, Didier; Marcu, Ioan–Cezar

doi:10.1016/j.cattod.2017.01.013

Cited by 32 publications

(16 citation statements)

References 54 publications

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“…For Mn solid, the particle size was greater in relation to the catalysts with Cu, so when adding Cu as an active phase there was a decrease in particle size, which could result in a better distribution in the catalyst. The smaller particle size of solid Mn-Cu (1:2) and Mn-Cu (2:1) indicated a good distribution of the active phase on the surface and therefore a possible better catalytic activity, which is evident in the reaction [27].…”

Section: Discussionmentioning

confidence: 98%

Degradation of Crystal Violet by Catalytic Wet Peroxide Oxidation (CWPO) with Mixed Mn/Cu Oxides

et al. 2019

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The environment protection has been the starting point for the development of new technologies, which allow the control of highly toxic substances present in the effluents of various industries, whose removal is not feasible by conventional methods. In this research, mixed oxide catalysts Mn and Cu in different molar ratios were prepared from the autocombustion method and characterized by XRD, XRF, TPR-H2, and N2 adsorption–desorption isotherms. The solids were evaluated in the catalytic wet peroxide oxidation of crystal violet (CV) with mild conditions of reaction: 25 °C, normal pressure, airflow of 2 mL/min, and H2O2 0.1 M (2 mL/h). The experimental results indicated degradations of 100% of CV, conversion of the total organic carbon (TOC) of 74%, and elimination of chemical oxygen demand (COD) of 71% in 90 min of reaction. Additionally, the selectivity was monitored by CG-MS, finding that there was almost complete mineralization in a short reaction time, generating intermediate products such as carboxylic acids, alcohols, and amines that do not cause a serious risk to the environment. The Mn–Cu catalyst with molar ratios of 1:2 was the most promising catalyst, displaying a cooperative effect between the two metals, and demonstrating the importance of the redox properties for the elimination of CV dye in wastewater.

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Section: Discussionmentioning

confidence: 98%

Degradation of Crystal Violet by Catalytic Wet Peroxide Oxidation (CWPO) with Mixed Mn/Cu Oxides

et al. 2019

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“…The analysis of both sets of TPR curves showed that the addition of Zr and/or Ce was beneficial for the catalysts’ reducibility, because it increased the contribution of the low-temperature feature and/or shifted the position of the main maximum to lower temperature. It has been repeatedly pointed out that quantitative interpretation of the TPR characteristics of mixed oxides containing both Mn and Cu were quite difficult, due to many factors influencing their reduction, in particular a number of different oxidation states of copper and manganese, which may have been involved in the process [ 8 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 32 , 33 , 34 , 35 , 36 ]. In the examined temperature range, Cu 2+ and/or Cu + underwent reduction to Cu 0 and Mn 4+ and/or Mn 3+ to Mn 2+ .…”

Section: Resultsmentioning

confidence: 99%

“…During World War I, the search for an efficient CO absorbent to be used in military gas masks resulted in the development of hopcalite catalysts—based on mixtures of Cu and Mn oxides—which are extremely efficient in CO oxidation [ 6 , 7 ]. Research into catalytic applications of the Cu–Mn–O system has been continued ever since, especially given that the materials show high activity in the total oxidation of VOCs [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. In several cases, hydrotalcite (Htlc)-like precursors, which, when thermally decomposed, yield mixed oxides of exceptional properties, were used [ 9 , 14 , 15 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Composites of Laponite and Cu–Mn Hopcalite-Related Mixed Oxides Prepared from Inverse Microemulsions as Catalysts for Total Oxidation of Toluene

et al. 2018

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Composites of Laponite and Cu–Mn hopcalite-related mixed oxides, prepared from hydrotalcite-like (Htlc) precursors obtained in inverse microemulsions, were synthesized and characterized with XRF, XRD, SEM, TEM, H2 temperature-programmed reduction (TPR), and N2 adsorption/desorption at −196 °C. The Htlc precursors were precipitated either with NaOH or tetrabutylammonium hydroxide (TBAOH). Al was used as an element facilitating Htlc structure formation, and Ce and/or Zr were added as promoters. The composites calcined at 600 °C are mesoporous structures with similar textural characteristics. The copper–manganite spinel phases formed from the TBAOH-precipitated precursors are less crystalline and more susceptible to reduction than the counterparts obtained from the precursors synthesized with NaOH. The Cu–Mn-based composites are active in the combustion of toluene, and their performance improves further upon the addition of promoters in the following order: Ce < Zr < Zr + Ce. The composites whose active phases are prepared with TBAOH are more active than their counterparts obtained with the use of the precursors precipitated with NaOH, due to the better reducibility of the less crystalline mixed oxide active phase.

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“…Besides, oxyspinels have been studied as excellent photocatalytic degradation for methylene blue [36,37] and methyl orange [38]. Meanwhile, several oxyspinels were prepared from inorganic anions (carbonate, nitrate, phosphate, and sulfate) pillared A 2+ -A 3+ layered double hydroxides and followed by a thermal process that they performed the improved catalytic activities [39][40][41][42][43][44][45][46]. Afterward, we study the improved photocatalytic degradation of pNP through a solar-responsive oxyspinel derived from organic anion pillared LDH precursors under UV-light irradiation.…”

Section: Introductionmentioning

confidence: 99%

An improved method for high photocatalytic performance of ZnAl2O4 spinel derived from layered double hydroxide precursor

Putra

2020

SN Appl. Sci.

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A spinel structure of zinc aluminate (ZnAl 2 O 4) particles provides a prospective material for photocatalytic applications. In this work, zinc aluminate spinel was prepared by an anion-exchange method derived from layered double hydroxides (LDHs) followed by thermal treatment. The mechanism, photoactivity, and effects of both anion substitute and temperature have been investigated. The chemical composition, morphologies, phase structures, porous structures and photocatalytic properties of samples were analyzed using thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, gas sorption analysis, and ultraviolet-visible spectroscopy in detail. The results of mesoporous α-ZnAl 2 O 4 indicate that average crystallite size, total pore volume, and BET surface area obtain 9.3 nm, 0.337 cm 3 /g, and 206.13 m 2 /g, respectively. Moreover, zinc aluminate spinel shows well phase after heating at 700 °C and LDHs structures were completely collapsed. The photocatalytic performances of α-ZnAl 2 O 4 have been applied in p-nitrophenol reduction under visible light irradiation and required time at least 9 min. Finally, the new improved method constructs an excellent material for pretreatment of liquid pollutants containing high-level concentration at rapid treatment time.

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Influence of Mn content on the catalytic properties of Cu-(Mn)-Zn-Mg-Al mixed oxides derived from LDH precursors in the total oxidation of methane

Cited by 32 publications

References 54 publications

Degradation of Crystal Violet by Catalytic Wet Peroxide Oxidation (CWPO) with Mixed Mn/Cu Oxides

Degradation of Crystal Violet by Catalytic Wet Peroxide Oxidation (CWPO) with Mixed Mn/Cu Oxides

Composites of Laponite and Cu–Mn Hopcalite-Related Mixed Oxides Prepared from Inverse Microemulsions as Catalysts for Total Oxidation of Toluene

An improved method for high photocatalytic performance of ZnAl2O4 spinel derived from layered double hydroxide precursor

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