Effect of Aging Methods on CuZnAl Catalysts for Methyl Acetate Hydrogenation

A series of CuZnAl catalysts derived from layered double hydroxide precursors with different Cu/Zn molar ratios were synthesised by a co-precipitation method for methyl acetate hydrogenation. The best catalytic performance was obtained when the Cu/Zn molar ratio reached 0.25:1. After fixing the Cu/Zn molar ratio at 0.25:1, the effect of aging methods, including ultrasound, high shear mixer stirring, and magnetic stirring, were investigated, which showed that 0.25CuZnAl-u and 0.25CuZnAl-h exhibited a higher conversion and selectivity than that of 0.25CuZnAl-m, especially under low reaction temperatures. The physicochemical properties of the CuZnAl catalysts were characterised by X-ray diffraction, inductively coupled plasma–atomic emission spectroscopy, N2 physisorption, N2O chemisorption, transmission electron microscopy, H2-temperature-programmed reduction, X-ray photoelectron spectroscopy, and H2-temperature-programmed desorption. It was found that compared with 0.25CuZnAl-m, 0.25CuZnAl-u and 0.25CuZnAl-h possessed a stronger interaction between Cu and the support, smaller copper particle size, and higher copper dispersion, which improved the catalytic performance.

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Generalized Methodology for Inserting Metal Heteroatoms into the Layered Zeolite Precursor RUB-36 by Interlayer Expansion

Crystals ◽

10.3390/cryst10060530 ◽

2020 ◽

Vol 10 (6) ◽

pp. 530 ◽

Cited By ~ 2

Author(s):

Chaoqun Bian ◽

Xiao Wang ◽

Lan Yu ◽

Fen Zhang ◽

Jie Zhang ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Catalytic Performance ◽

X Ray Diffraction ◽

Zeolite Sample ◽

X Ray ◽

Inductively Coupled ◽

Temperature Programmed ◽

First Time ◽

N2 Sorption

The incorporation of metal heteroatoms into zeolites is an effective modification strategy for enhancing their catalytic performance. Herein, for the first time we report a generalized methodology for inserting metal heteroatoms (such as Sn, Fe, Zn, and Co) into the layered zeolite precursor RUB-36 via interlayer expansion by using the corresponding metal acetylacetate salt. Through this generalized methodology, Sn-JHP-1, Fe-JHP-1, Zn-JHP-1 and Co-JHP-1 zeolites could be successfully prepared by the reaction of RUB-36 and corresponding metal acetylacetate salt at 180 °C for 24 h in the presence of HCl solution. As a typical example, Sn-JHP-1 and calcined Sn-JHP-1 (Sn-JHP-2) zeolite is well characterized by the X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible (UV-Vis), inductively coupled plasma (ICP), N2 sorption, temperature-programmed-desorption of ammonia (NH3-TPD) and X-ray photoelectron spectroscopy (XPS) techniques, which confirm the expansion of adjacent interlayers and thus the incorporation of isolated Sn sites within the zeolite structure. Notably, the obtained Sn-JHP-2 zeolite sample shows enhanced catalytic performance in the conversion of glucose to levulinic acid (LA) reaction.

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Synthesis of DME by CO2 hydrogenation over La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq150711005z ◽

2017 ◽

Vol 23 (1) ◽

pp. 49-56 ◽

Cited By ~ 2

Author(s):

Yajing Zhang ◽

Yu Zhang ◽

Fu Ding ◽

Kangjun Wang ◽

Wang Xiaolei ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Direct Synthesis ◽

Catalytic Performance ◽

Co2 Hydrogenation ◽

Precipitation Method ◽

X Ray ◽

Temperature Programmed ◽

And Performance ◽

Co Precipitation ◽

Adsorption Desorption

A series of La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts were prepared by an oxalate co-precipitation method. The catalysts were fully characterized by X-ray diffraction (XRD), N2 adsorption-desorption, hydrogen temperature pro-grammed reduction (H2-TPR), ammonia temperature programmed desorption (NH3-TPD), and X-ray photoelectron spectroscopy (XPS) techniques. The effect of the La2O3 content on the structure and performance of the catalysts was thoroughly investigated. The catalysts were evaluated for the direct synthesis of dimethyl ether (DME) from CO2 hydrogenation. The results displayed that La2O3 addition enhanced catalytic performance, and the maximal CO2 conversion (34.3%) and DME selectivity (57.3%) were obtained over the catalyst with 1% La2O3, which due to the smaller size of Cu species and a larger ratio of Cu+/Cu.

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The Modification of Pt/Graphene Composites with Oxophilic Metal Bi (Bi2O3) and Its Dual-Functional Electro-Photo Catalytic Performance

Catalysts ◽

10.3390/catal8100465 ◽

2018 ◽

Vol 8 (10) ◽

pp. 465

Author(s):

Yingli Wu ◽

Xiuyun Duan ◽

Zhongshui Li ◽

Shuhong Xu ◽

Yixin Xie ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Electric Energy ◽

Atomic Emission ◽

Catalytic Performance ◽

Water Soluble ◽

Methanol Oxidation Reaction ◽

Solution Synthesis ◽

X Ray ◽

Electrocatalytic Properties

The Pt-Bi (Bi2O3)/GNs (PVP) composite was synthesized using aqueous solution synthesis and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Raman spectroscopy. It was found that the water-soluble polyvinyl pyrrolidone (PVP) helped to tune the particles’ morphology, resulting in a uniform distribution of Pt-Bi nanoclusters on the surface of graphene. Cyclic voltammetry, chronoamperometry and linear scanning voltammetry (LSV) were used to study the electrocatalytic properties towards a methanol oxidation reaction (MOR) and an oxygen reduction reaction (ORR). The results show that Pt-Bi (Bi2O3)/GNs (PVP) exhibits superior bifunctional electrocatalytic properties for both MOR and ORR, mainly due to the introduction of oxophilic Bi species and the better dispersion of the Pt-Bi nanoclusters. In particular, the electro-photo catalysis for both MOR and ORR occurred under simulated sunlight irradiation due to the existence of photo-responsive Bi species, which is helpful for converting solar energy into electric energy during a traditional electrocatalytic process.

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The Effect of Mg and Zn Dopants on Pt/Al2O3 for the Dehydrogenation of Perhydrodibenzyltoluene

Catalysts ◽

10.3390/catal11040490 ◽

2021 ◽

Vol 11 (4) ◽

pp. 490

Author(s):

Rudaviro Garidzirai ◽

Phillimon Modisha ◽

Innocent Shuro ◽

Jacobus Visagie ◽

Pieter van Helden ◽

...

Keyword(s):

Electron Microscopy ◽

Inductively Coupled Plasma ◽

Flow Reactor ◽

Plug Flow ◽

Optical Emission ◽

Catalytic Performance ◽

Emission Spectrometry ◽

Hydrogen Yield ◽

X Ray ◽

Temperature Programmed

The effects of Mg and Zn dopants on the catalytic performance of Pt/Al2O3 catalyst were investigated for dehydrogenation of perhydrodibenzyltoluene (H18-DBT) as a liquid organic hydrogen carrier. Al2O3 supports were modified with Mg and Zn to produce Mg-Al2O3 and Zn-Al2O3 with a target loading of 3.8 wt.% for dopants. The modified supports were impregnated with chloroplatinic acid solution to produce the catalysts Pt/Al2O3, Pt/Mg-Al2O3 and Pt/Zn-Al2O3 of 0.5 wt.% Pt loading. Thereafter, the catalysts were characterised using inductively coupled plasma- optical emission spectrometry, scanning electron microscopy-energy dispersive X-ray spectroscopy, hydrogen temperature-programmed reduction, carbon-monoxide pulse chemisorption, ammonia temperature-programmed desorption, X-ray diffraction and transmission electron microscopy. The dehydrogenation experiments were performed using a horizontal plug flow reactor system and the catalyst time-on-stream was 22 h. Pt/Mg-Al2O3 showed the highest average hydrogen flowrate of 29 nL/h, while an average of 27 nL/h was obtained for both Pt/Al2O3 and Pt/Zn-Al2O3. This has resulted in a hydrogen yield of 80% for Pt/Mg-Al2O3, 71% for Pt/Zn-Al2O3 and 73% for Pt/Al2O3. In addition, the conversion of H18-DBT ranges from 99% to 92%, Pt 97–90% and 96–90% for Pt/Mg-Al2O3, Pt/Zn-Al2O3 and Pt/Al2O3, respectively. Following the latter catalyst order, the selectivity to dibenzyltoluene (H0-DBT) ranges from 78% to 57%, 75–51% and 71–45%. Therefore, Pt/Mg-Al2O3 showed improved catalytic performance towards dehydrogenation of H18-DBT.

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Influence of Sulfur-Containing Sodium Salt Poisoned V2O5–WO3/TiO2 Catalysts on SO2–SO3 Conversion and NO Removal

Catalysts ◽

10.3390/catal8110541 ◽

2018 ◽

Vol 8 (11) ◽

pp. 541 ◽

Cited By ~ 3

Author(s):

Haiping Xiao ◽

Chaozong Dou ◽

Hao Shi ◽

Jinlin Ge ◽

Li Cai

Keyword(s):

Photoelectron Spectroscopy ◽

No Reduction ◽

Catalytic Performance ◽

Acid Sites ◽

Impregnation Method ◽

So2 Oxidation ◽

Sodium Salts ◽

X Ray ◽

Temperature Programmed ◽

Physical Features

A series of poisoned catalysts with various forms and contents of sodium salts (Na2SO4 and Na2S2O7) were prepared using the wet impregnation method. The influence of sodium salts poisoned catalysts on SO2 oxidation and NO reduction was investigated. The chemical and physical features of the catalysts were characterized via NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed that sodium salts poisoned catalysts led to a decrease in the denitration efficiency. The 3.6% Na2SO4 poisoned catalyst was the most severely deactivated with denitration efficiency of only 50.97% at 350 °C. The introduction of SO42− and S2O72− created new Brønsted acid sites, which facilitated the adsorption of NH3 and NO reduction. The sodium salts poisoned catalysts significantly increased the conversion of SO2–SO3. 3.6%Na2S2O7 poisoned catalyst had the strongest effect on SO2 oxidation and the catalyst achieved a maximum SO2–SO3-conversion of 1.44% at 410 °C. Characterization results showed sodium salts poisoned catalysts consumed the active ingredient and lowered the V4+/V5+ ratio, which suppressed catalytic performance. However, they increased the content of chemically adsorbed oxygen and the strength of V5+=O bonds, which promoted SO2 oxidation.

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Surface Characterization of W/Ni/Al2O3 Catalysts

MRS Proceedings ◽

10.1557/proc-497-243 ◽

1997 ◽

Vol 497 ◽

Author(s):

M. H. Jordão ◽

J. M. Assaf ◽

P. A. P. Nascente

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Surface Characterization ◽

Nickel Content ◽

Stable Phase ◽

Preparation Methods ◽

X Ray ◽

Inductively Coupled ◽

Temperature Programmed ◽

Two Phases

ABSTRACTCatalysts containing tungsten and nickel oxides are important in hydrodesulfurization (HDS), hydrogénation (HY), and steam reforming of hydrocarbons. A series of W/Ni/Al2O3 catalysts was prepared by two different methods: (1) coprecipitation of nickel and aluminium hydroxicarbonate from their nitrates, followed by calcination and impregnation of tungsten; (2) precipitation of boehmite from aluminium nitrate, followed by impregnations of nickel, firstly, and tungsten. The nickel content was kept constant, while the amount of tungsten varied from 2.5 to 15.5 wt-%. The resulting oxides were characterized by inductively coupled plasma spectroscopy (ICP), atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). ICP and AAS were used to determine the W, Ni, and Al concentrations. XRD detected two phases: NiO and NiAl2O4 (no phase containing metallic tungsten was detected). Increasing the amount of W, the quantity of NiAl2O4 rose, the quantity of NiO decreased, and the particle size of NiO enlarged. The TPR profiles presented three peaks: one at about 1000 °C, associated to a very stable phase; for the samples prepared by coprecipitation, the other two peaks corresponded to “free NiO” and a nonstoichiometric aluminate. For the samples prepared by impregnation, those peaks corresponded to NiO and NiAl2O4. XPS identified Al2O3, NiAl2O4, and Al2(WO4)3 for both preparation methods. Increasing the amount of tungsten in the impregnated samples, NiWO4 was also observed.

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Hydroformylation of Dicyclopentadiene over Rh Catalysts Supported on Fe2O3, Co3O4 and Fe2O3–Co3O4 Mixed Oxide

Progress in Reaction Kinetics and Mechanism ◽

10.3184/146867817x14806858831947 ◽

2017 ◽

Vol 42 (1) ◽

pp. 8-13 ◽

Cited By ~ 4

Author(s):

Yubo Ma ◽

Zhixian Gao ◽

Wumanjiang Eli

Keyword(s):

Mixed Oxide ◽

Photoelectron Spectroscopy ◽

Supported Catalyst ◽

Precipitation Method ◽

X Ray ◽

Analysis Techniques ◽

Rh Catalyst ◽

Temperature Programmed ◽

Co Precipitation ◽

Effect Of The Support

Rh catalysts supported on Fe2O3, Co3O4 and Fe2O3–Co3O4 mixed oxide were prepared by the co-precipitation method. The effect of the support on the performance of the Rh catalysts for the hydroformylation of dicyclopentadiene was investigated using X-ray photoelectron spectroscopy, H2-temperature-programmed reduction, H2-temperature-programmed desorption and Brunauer–Emmett–Teller analysis techniques. The results indicated that the Fe2O3–Co3O4 supported catalyst had a higher dispersion of Rh and thus more Rh+ sites. As a result, the Fe2O3–Co3O4 supported Rh catalyst exhibited higher activity compared with counterparts supported on Fe2O3 and Co3O4.

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Fe-Containing MOFs as Seeds for the Preparation of Highly Active Fe/Al-SBA-15 Catalysts in the NAlkylation of Aniline

Molecules ◽

10.3390/molecules24152695 ◽

2019 ◽

Vol 24 (15) ◽

pp. 2695 ◽

Cited By ~ 1

Author(s):

Mhadmhan ◽

Marquez-Medina ◽

Romero ◽

Reubroycharoen ◽

Luque

Keyword(s):

Photoelectron Spectroscopy ◽

Inductively Coupled Plasma ◽

Catalytic Performance ◽

Alkylation Reaction ◽

X Ray Diffraction ◽

X Ray ◽

Inductively Coupled ◽

Highly Active ◽

Milling Method ◽

Plasma Mass Spectrometry

We have successfully incorporated iron species into mesoporous aluminosilicates (AlSBA15) using a simple mechanochemical milling method. The catalysts were characterized by nitrogen physisorption, inductively coupled plasma mass spectrometry (ICP-MS), pyridine (PY) and 2,6-dimethylpyridine (DMPY) pulse chromatography titration, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The catalysts were tested in the N-alkylation reaction of aniline with benzyl alcohol for imine production. According to the results, the iron sources, acidity of catalyst and reaction conditions were important factors influencing the reaction. The catalyst showed excellent catalytic performance, achieving 97% of aniline conversion and 96% of imine selectivity under optimized conditions.

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Heterogeneous Fenton-like oxidation of p-hydroxybenzoic acid using Fe/CeO2-TiO2 catalyst

Water Science & Technology ◽

10.2166/wst.2019.119 ◽

2019 ◽

Vol 79 (7) ◽

pp. 1276-1286 ◽

Cited By ~ 3

Author(s):

Tijani Hammedi ◽

Mohamed Triki ◽

Mayra G. Alvarez ◽

Jordi Llorca ◽

Abdelhamid Ghorbel ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Catalytic Properties ◽

Molar Ratio ◽

Hydroxybenzoic Acid ◽

X Ray ◽

Transmission Electron ◽

Scanning Transmission ◽

Temperature Programmed

Abstract This paper is built on the Fenton-like oxidation of p-hydroxybenzoic acid (p–HBZ) in the presence of H2O2 and 3%Fe supported on CeO2-TiO2 aerogels under mild conditions. These catalysts were deeply characterized by X-ray diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS). The effect of thermal treatment, pH (2–3, 5, 7), H2O2/p–HBZ molar ratio (5, 15, 20, 25) and reaction temperature (25 °C, 40 °C and 60 °C) on the catalytic properties of supported Fe catalysts are studied. Our results highlight the role of CeO2 and the calcination of the catalyst to obtain the highest catalytic properties after 10 min: 73% of p–HBZ conversion and 52% of total organic carbon (TOC) abatement.

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Effect of Y Modified Ceria Support in Mono and Bimetallic Pd–Au Catalysts for Complete Benzene Oxidation

Catalysts ◽

10.3390/catal8070283 ◽

2018 ◽

Vol 8 (7) ◽

pp. 283 ◽

Cited By ~ 6

Author(s):

Lyuba Ilieva ◽

Anna Venezia ◽

Petya Petrova ◽

Giuseppe Pantaleo ◽

Leonarda Liotta ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalytic Performance ◽

Precipitation Method ◽

Benzene Oxidation ◽

Total Oxidation ◽

Pd Catalysts ◽

X Ray ◽

Close Relationship ◽

Ceria Support ◽

Co Precipitation

Mono metallic and bimetallic Pd (1 wt. %)–Au (3 wt. %) catalysts were prepared using two ceria supports doped with 1 wt. % Y2O3. Yttrium was added by impregnation or co-precipitation. The catalyst synthesis was carried out by deposition–precipitation method, with sequential deposition–precipitation of palladium over previously loaded gold in the case of the bimetallic samples. The obtained materials, characterized by X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR) techniques, were tested in the complete benzene oxidation (CBO). The results of the characterization analyses and the catalytic performance pointed to a close relationship between structural, redox, and catalytic properties of mono and bimetallic catalysts. Among the monometallic systems, Pd catalysts were more active as compared to the corresponding Au catalysts. The bimetallic systems exhibited the best combustion activity. In particular, over Pd–Au supported on Y-impregnated ceria, 100% of benzene conversion towards total oxidation at the temperature of 150 °C was obtained. Comparison of surface sensitive XPS results of fresh and spent catalysts ascertained the redox character of the reaction.

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