Regeneration of Pd/TiO2 catalyst deactivated in reductive CCl4 transformations by the treatment with supercritical CO2, ozone in supercritical CO2 or oxygen plasma

Локтева, Е. С.; Lazhko, A. E.; Голубина, Е. В.; Timofeev, V. V.; Naumkin, A. V.; Yagodovskaya, T. V.; Gaidamaka, S. N.; Лунин, В. В.

doi:10.1016/j.supflu.2011.05.018

Cited by 22 publications

(6 citation statements)

References 23 publications

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“…In line with these applications, plasma technique can also be applied in catalyst regeneration at low temperature and pressure avoiding any internal destruction [24][25][26][27][28]. It has been previously shown that the dielectric barrier discharge plasma is able to effectively oxidize diesel carbon soot.…”

Section: Introductionmentioning

confidence: 99%

Improving Plasma Regeneration Conditions of Pt–Sn/Al2O3 in Naphtha Catalytic Reforming Process Using Atmospheric DBD Plasma System

Hafezkhiabani

Fathi

Shokri

2015

Plasma Chem Plasma Process

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The catalytic naphtha reforming is one of the largest processes of petroleum industry that is used to rebuild the low-octane hydrocarbons in the naphtha to more valuable high-octane gasoline called reformate without changing the boiling point range. An atmospheric pressure pin to plate dielectric barrier discharge (DBD) plasma was used to remove carbonaceous contaminant from the coked Pt-Sn/Al 2 O 3 catalysts during the naphtha reforming process. The effects of treatment time and flow ratios of O 2 /Ar and O 2 / He on the carbon content of the coked catalysts were investigated. The produced radicals and active species of the plasma process were identified by optical emission spectroscopy. To confirm removing the coke from the catalyst, thermal gravimetric/differential thermal analysis and temperature programmed oxidation analysis were done. Effects of treatment time and flow ratios of O 2 /Ar and O 2 /He on the carbon content of the coked catalysts were investigated by applying elemental analysis. The results of X-ray diffraction, X-ray fluorescence, Brunauer-Emmett-Teller, and CO adsorption showed that the structure and specifications of regenerated catalysts remained without significant changes during the plasma treating. The catalyst performance test revealed that DBD plasma regenerated catalysts increased the aromatic content of the feed as well as the fresh catalysts. The results showed that the plasma treatment method for regeneration of Pt-Sn/Al 2 O 3 can be applied at lower temperature and pressure relative to the thermal regeneration method.

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Section: Introductionmentioning

confidence: 99%

Improving Plasma Regeneration Conditions of Pt–Sn/Al2O3 in Naphtha Catalytic Reforming Process Using Atmospheric DBD Plasma System

Hafezkhiabani

Fathi

Shokri

2015

Plasma Chem Plasma Process

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“…A CeO 2 –ZrO 2 solid solution that was produced by simultaneously introducing Ce and Zr additives exhibited better thermal stability and oxygen storage capacity than CeO 2 alone. − However, despite a tremendous amount of research, the rapid deactivation of nickel-based catalysts is still observed due to sintering or carbon deposition at high temperature. , Therefore, methods to regenerate the catalysts as well as evaluate their performance must be developed . Typical regenerative approaches have involved the use of organic solvents, abrasion or ultrasonication, or supercritical fluids or plasmas to remove deposited carbon from the surfaces of the catalysts. Nevertheless, the high cost or complexity of these methods has limited their large-scale development.…”

Section: Introductionmentioning

confidence: 99%

“…8,9 Therefore, methods to regenerate the catalysts as well as evaluate their performance must be developed. 10 Typical regenerative approaches have involved the use of organic solvents, 11 abrasion or ultrasonication, 12 or supercritical fluids or plasmas 13 to remove deposited carbon from the surfaces of the catalysts. Never-theless, the high cost or complexity of these methods has limited their large-scale development.…”

Section: Introductionmentioning

confidence: 99%

Cracking Characteristics of Simulated Dust-Containing Coal Pyrolysis Volatiles over Regenerated Nickel-Based Catalysts

et al. 2015

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Two catalysts, 2%NiO/1%CeO 2 −Al 2 O 3 and 2%NiO/1%CeO 2 /2%ZrO 2 −Al 2 O 3 , were employed in the conversion of tar in coal pyrolysis volatiles to investigate the interrelationship between dust collection and tar cracking as well as the effect of Ce/Zr doping on catalyst performance. In a fixed-bed catalytic reactor, a tar model mixture (57 wt % toluene, 14 wt % methylnaphthalene, 14 wt % cyclohexane, and 15 wt % dodecane) and simulated dusts (various metal oxides) were introduced to mimic real coal pyrolysis volatiles. The catalytic cracking activity of the latter catalyst increased with increasing temperature, space velocity, and water/model tar ratio, whereas the former catalyst exhibited the opposite trends, except with respect to temperature. Because of the formation of a Ce−ZrO 2 solid solution, the latter catalyst showed higher stability. During cycling tests, the deactivation of 2%NiO/1%CeO 2 −Al 2 O 3 was observed in the seventh reaction-regeneration cycle. Nickel aggregation, observed on the surface of the catalyst by XRD analysis, may account for the deactivation. Dust deposition on the catalyst surface had a significant influence on tar modification, and the interaction mechanism between dust deposition and coke formation was clarified. The electron probe microanalysis results showed that SiO 2 tends to promote carbon deposition, whereas MgO and Fe 2 O 3 components have a negative influence on carbon deposition. This study can serve as a reliable reference for the practical development and modification of purification processes for coal pyrolysis volatiles.

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“…The regeneration effectiveness can be attributed to chemical and thermal effects of plasma such as the formation of reactive intermediates and cost-effective catalyst heat-up due to low-temperature activation (Lee et al, 2019). Zhu et al (2015) reported that Au/TiO 2 catalysts deactivated through CO oxidation were effectively regenerated by atmosphericpressure air DBD plasma initiated through a high-voltage AC source with a frequency of 1.8 kHz and an input power of 3 W. In contrast, Lokteva et al (2011) applied a glow-discharge O 2 plasma treatment for the recovery of Pd/TiO 2 catalyst deactivated due to carbonaceous deposits. A sputtering reactor operated at an AC voltage frequency of 50 Hz, amplitude of 1,500 V, and current of 150 mA was used for discharge maintenance for 20 min at low pressure (120 Pa).…”

Section: Plasma Modification Of Supported Metal Catalysts After Prepamentioning

confidence: 99%

The Potential of Non-thermal Plasmas in the Preparation of Supported Metal Catalysts for Fuel Conversion in Automotive Systems: A Literature Overview

2020

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The growing demand for energy worldwide and the extensive use of fossil fuels have resulted in severe environmental problems such as air pollution and the accumulation of greenhouse gases in the atmosphere. In this scenario, both new energy sources and more efficient energy conversion processes have been deeply studied. Heterogeneous catalysis is currently widely used for hydrogen production due to its higher selectivity and conversion compared to other processes. Although the use of catalysts is fundamental for green chemistry, their production through traditional methods is less environmentally friendly. Nonetheless, in order to obtain more efficient supported metal catalysts, interest in using non-thermal plasma as a pretreatment or synthesis technique is increasing. Thus, the present article aims at summarizing and briefly discussing the relevant research results on this subject, elucidating the advantages and disadvantages of using nonthermal plasmas in the preparation of supported metal catalysts. Aspects such as morphology, the chemical composition of the catalytic surface, crystallographic phases, average size and dispersion of crystallites, specific surface area, and metal-support interaction have been analyzed. The use of plasma-assisted techniques contributes to the synthesis of supported metal catalysts with smaller, more dispersed, and strongly bonded active particles, resulting in higher catalytic activity, conversion rate, selectivity, and durability. In addition, plasma allows the synthesis of supported metal catalysts to be enhanced by reducing the process time, the use of hazardous substances, and the temperature required.

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Regeneration of Pd/TiO2 catalyst deactivated in reductive CCl4 transformations by the treatment with supercritical CO2, ozone in supercritical CO2 or oxygen plasma

Cited by 22 publications

References 23 publications

Improving Plasma Regeneration Conditions of Pt–Sn/Al2O3 in Naphtha Catalytic Reforming Process Using Atmospheric DBD Plasma System

Improving Plasma Regeneration Conditions of Pt–Sn/Al2O3 in Naphtha Catalytic Reforming Process Using Atmospheric DBD Plasma System

Cracking Characteristics of Simulated Dust-Containing Coal Pyrolysis Volatiles over Regenerated Nickel-Based Catalysts

The Potential of Non-thermal Plasmas in the Preparation of Supported Metal Catalysts for Fuel Conversion in Automotive Systems: A Literature Overview

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