Correlating the Structural Evolution of ZnO/Al2O3 to Spinel Zinc Aluminate with its Catalytic Performance in Propane Dehydrogenation

Zn-based Al2O3-suported materials have been proposed as inexpensive and environmentally friendly catalysts for the direct dehydrogenation of propane (PDH), however, our understanding of these catalysts’ structure and deactivation routes is still limited. Here, we correlate the catalytic activity for PDH of a series of Zn-based Al2O3 catalysts with their structure and structural evolution. To this end, three model catalysts are investigated. (i) ZnO/Al2O3 prepared by atomic layer deposition (ALD) of ZnO onto γ-Al2O3 followed by calcination at 700 °C, which yields a core-shell spinel zinc aluminate/γ-Al2O3 structure. (ii) Zinc aluminate spinel nanoparticles (ZnxAlyO4 NPs) prepared via a hydrothermal method. (iii) A reference core-shell ZnO/SiO2 catalyst prepared by ALD of ZnO on SiO2. The catalysts are characterized in detail by synchrotron X-ray powder diffraction (XRD), Zn K-edge X-ray absorption spectroscopy (XAS), and 27Al solid state nuclear magnetic resonance (ssNMR). These experiments allowed us to identify tetrahedral Zn sites in close proximity to Al sites of a zinc aluminate spinel phase (ZnIV–O–AlIV/VI linkages) as notably more active and selective in PDH relative to the supported ZnO wurtzite phase (ZnIV–O– ZnIV linkages) in ZnO/SiO2. The best performing catalyst, 50ZnO/Al2O3 gives 77% selectivity to propene (gaseous products based) at 9 mmol C3H6 gcat−1 h−1 space time yield (STY) after 3 min of reaction at 600 °C. On the other hand, the core-shell ZnO/Al2O3 catalyst shows an irreversible loss of activity over repeated PDH and air-regeneration cycles, explained by Zn depletion on the surface due to its diffusion into subsurface layers or the bulk. ZnxAlyO4 NPs gave a comparable initial selectivity and catalytic activity as 50ZnO/Al2O3. With time on stream, ZnxAlyO4 NPs deactivate due to the formation of coke at the catalyst surface, yet the extend of coke deposition is lower than for the ZnO/Al2O3 catalysts, and the activity of ZnxAlyO4 NPs can be regenerated almost fully using calcination in air.

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Structure-Dependent Mechanical Properties of ALD-Grown Nanocrystalline BiFeO3Multiferroics

Journal of Nanomaterials ◽

10.1155/2016/5348471 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Anna Majtyka ◽

Anna Nowak ◽

Benoît Marchand ◽

Dariusz Chrobak ◽

Mikko Ritala ◽

...

Keyword(s):

Mechanical Properties ◽

Photoelectron Spectroscopy ◽

Present Report ◽

Structural Evolution ◽

Atomic Layer ◽

Grazing Incidence ◽

X Ray Diffraction ◽

X Ray ◽

Layer Deposition ◽

Pertinent Information

The present paper pertains to mechanical properties and structure of nanocrystalline multiferroic BeFiO3(BFO) thin films, grown by atomic layer deposition (ALD) on the Si/SiO2/Pt substrate. The usage of sharp-tip-nanoindentation and multiple techniques of structure examination, namely, grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry, enabled us to detect changes in elastic properties(95 GPa≤E≤118 GPa)and hardness(4.50 GPa≤H≤7.96 GPa)of BFO after stages of annealing and observe their relation to the material’s structural evolution. Our experiments point towards an increase in structural homogeneity of the samples annealed for a longer time. To our best knowledge, the present report constitutes the first disclosure of nanoindentation mechanical characteristics of ALD-fabricated BeFiO3, providing a new insight into the phenomena that accompany structure formation and development of nanocrystalline multiferroics. We believe that our systematic characterization of the BFO layers carried out at consecutive stages of their deposition provides pertinent information which is needed to control and optimize its ALD fabrication.

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Catalytic Activity of Polynuclear vs. Dinuclear Aroylhydrazone Cu(II) Complexes in Microwave-Assisted Oxidation of Neat Aliphatic and Aromatic Hydrocarbons

Molecules ◽

10.3390/molecules24010047 ◽

2018 ◽

Vol 24 (1) ◽

pp. 47 ◽

Cited By ~ 13

Author(s):

Manas Sutradhar ◽

Tannistha Barman ◽

Armando Pombeiro ◽

Luísa Martins

Keyword(s):

Catalytic Activity ◽

Aromatic Hydrocarbons ◽

Catalytic Performance ◽

Antiproliferative Agents ◽

One Dimensional ◽

X Ray ◽

X Ray Crystallography ◽

Mild Conditions ◽

Microwave Assisted ◽

Aliphatic And Aromatic Hydrocarbons

One-dimensional (1D) polynuclear Cu(II) complex (1) derived from (5-bromo-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L) is synthesized and characterized by elemental analysis, IR spectroscopy, ESI-MS, and single crystal X-ray crystallography. Its catalytic performance towards the solvent-free microwave-assisted peroxidative oxidation of aliphatic and aromatic hydrocarbons under mild conditions is compared with that of dinuclear Cu(II) complexes (2 and 3) of the same ligand, previously reported as antiproliferative agents. Polymer 1 exhibits the highest activity, either for the oxidation of cyclohexane (leading to overall yields, based on the alkane, of up to 39% of cyclohexanol and cyclohexanone) or towards the oxidation of toluene (selectively affording benzaldehyde up to a 44% yield), after 2 or 2.5 h of irradiation at 80 or 50 °C, respectively.

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Synthesis of Sulfonic Acid-Functionalized Zirconium Poly(Styrene-Phenylvinyl-Phosphonate)-Phosphate for Heterogeneous Epoxidation of Soybean Oil

Catalysts ◽

10.3390/catal9090710 ◽

2019 ◽

Vol 9 (9) ◽

pp. 710 ◽

Cited By ~ 1

Author(s):

Xiaochuan Zou ◽

Xuyuan Nie ◽

Zhiwen Tan ◽

Kaiyun Shi ◽

Cun Wang ◽

...

Keyword(s):

Catalytic Activity ◽

Soybean Oil ◽

Sulfonic Acid ◽

Solid Acid ◽

Solid Acid Catalyst ◽

Acid Catalyst ◽

Thiol Group ◽

Catalytic Performance ◽

X Ray ◽

Sulfonic Acid Groups

In this paper, a solid acid catalyst (ZPS–PVPA–SO3H) was prepared by anchoring thiol group on zirconium poly(styrene-phenylvinyl-phosphonate)-phosphate (ZPS–PVPA), followed by oxidation of thiol groups to obtain sulfonic acid groups. The solid acid catalyst was characterized by XPS, X-ray, EDS, SEM, and TG-DSC. The successful preparation of sulfonic acid-functionalized ZPS–PVPA was confirmed. Subsequently, the catalytic performance of ZPS–PVPA–SO3H was investigated in the epoxidation of soybean oil. The results demonstrated that ZPS–PVPA–SO3H can effectively catalyze epoxidation of soybean oil with TBHP as an oxidant. Moreover, there was no significant decrease in catalytic activity after 5 repeated uses of the ZPS–PVPA–SO3H. Interestingly, the ZPS–PVPA–SO3H was kept in 2 mol/L of HCl overnight after the end of the seventh reaction, and the catalytic activity was gradually restored during the eighth to tenth cycles.

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Core-Shell Structural Evolution of Crystalline Silicon Nanoparticles upon Lithiation/Delithiation By Ex Situ Raman Spectroscopy and Operando Synchrotron X-Ray Diffraction

ECS Meeting Abstracts ◽

10.1149/ma2016-01/2/262 ◽

2016 ◽

Keyword(s):

Raman Spectroscopy ◽

Silicon Nanoparticles ◽

Crystalline Silicon ◽

Structural Evolution ◽

Ex Situ ◽

Core Shell ◽

X Ray Diffraction ◽

X Ray

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The Different Morphology of Co3O4 Catalysts and Application in the Abatement of Carbon Monoxide

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19527 ◽

2021 ◽

Vol 21 (12) ◽

pp. 6082-6087

Author(s):

Chih-Wei Tang ◽

Hsiang-Yu Shih ◽

Ruei-Ci Wu ◽

Chih-Chia Wang ◽

Chen-Bin Wang

Keyword(s):

Carbon Monoxide ◽

Catalytic Activity ◽

Co Oxidation ◽

Nitrogen Adsorption ◽

Catalytic Performance ◽

Precipitation Method ◽

X Ray Diffraction ◽

X Ray ◽

Temperature Programmed ◽

Adsorption Desorption

The increase of harmful carbon monoxide (CO) caused by incomplete combustion can affect human health even lead to suffocation. Therefore reducing the CO discharged by vehicles or factories is urgent to improve the air quality. The spinel cobalt (II, III) oxide (Co3O4) is an active catalyst for CO abatement. In this study, we tried to fabricate dispersing Co3O4 via the dispersion-precipitation method with acetic acid, formic acid, and oxalic acid as the chelating dispersants. Then, the asprepared samples were calcined at 300 ºC for 4 h to obtain active catalysts, and assigned as Co(A), Co(F) and Co(O) respectively, the amount of the dispersants used are labeled as I (0.12 mole), II (0.03 mole) and III (0.01 mole). For comparison, another CoAP sample was prepared via alkaliinduced precipitation and calcined at 300 ºC. All samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), scanning electron microscope (SEM), and nitrogen adsorption/desorption system, and the catalytic activity focused on the CO oxidation. The influence of chelating dispersant on the performance of abatement of CO was pursued in this study. Apparently, the results showed that the chelating dispersant can influence the catalytic activity of CO abatement. An optimized ratio of dispersant can improve the performance, while excess dispersant lessens the surface area and catalytic performance. The series of Co(O) samples can easily donate the active oxygen since the labile Co–O bonding and indicated the preferential performance than both Co(A) and Co(F) samples. The nanorod Co(O)-II showed preferential for CO oxidation, T50 and T90 approached 96 and 127 ºC, respectively. Also, the favorable durability of Co(O)-II sample maintains 95% conversion still for 50 h at 130 ºC and does not emerge deactivation.

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Synthesis and Characteristic of NiFe/NiFe2O4 Core-Shell Magnetic Nanocomposite Particles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.486.65 ◽

2012 ◽

Vol 486 ◽

pp. 65-69

Author(s):

Jun Hu ◽

Ai Min Chen

Keyword(s):

Structural Evolution ◽

Treatment Temperature ◽

Oxide Shell ◽

Core Shell ◽

Nanocomposite Particles ◽

X Ray ◽

The Core ◽

Transmission Electron ◽

Diffraction Patterns ◽

Feni Alloy

NiFe/NiFe2O4 core-shell bimagnetic nanocomposite particles were successfully synthesized by colloidal chemical method combined with H2 reduction. The whole structural evolution process has been well studied through analysis of X-ray diffraction patterns and Infrared spectra. It has been found that FeNi alloy concentrated in the ferrite phase. The core/shell structure, a FeNi alloy core surrounded by NiFe2O4 spinel oxide shell were verified by X-ray powder diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The influence of post H2 heat treatment temperature on nanoparticles was investigated. The core-shell NiFe/ NiFe2O4 nanoparticles was about 100 nm after reduced at 727 K, The powders exhibited paramagnetic properties and the magnetization was 29.9 emu·g-1.

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Effect of Direct Reduction Treatment on Pt–Sn/Al2O3 Catalyst for Propane Dehydrogenation

Catalysts ◽

10.3390/catal9050446 ◽

2019 ◽

Vol 9 (5) ◽

pp. 446 ◽

Cited By ~ 7

Author(s):

Jae-Won Jung ◽

Won-Il Kim ◽

Jeong-Rang Kim ◽

Kyeongseok Oh ◽

Hyoung Lim Koh

Keyword(s):

Catalytic Activity ◽

Photoelectron Spectroscopy ◽

Direct Reduction ◽

Coke Formation ◽

Catalytic Performance ◽

Propane Dehydrogenation ◽

X Ray ◽

Transmission Electron ◽

Calcination Step ◽

Xrd Patterns

Pt–Sn/Al2O3 catalysts were prepared by the direct reduction method at temperatures from 450 to 900 °C, denoted as an SR series (SR450 to SR900 according to reduction temperature). Direct reduction was performed immediately after catalyst drying without a calcination step. The activity of SR catalysts and a conventionally prepared (Cal600) catalyst were compared to evaluate its effect on direct reduction. Among the SR catalysts, SR550 showed overall higher conversion of propane and propylene selectivity than Cal600. The nano-sized dispersion of metals on SR550 was verified by transmission electron microscopy (TEM) observation. The phases of the bimetallic Pt–Sn alloys were examined by X-ray diffraction, TEM, and energy dispersive X-ray spectroscopy (EDS). Two characteristic peaks of Pt3Sn and PtSn alloys were observed in the XRD patterns, and these phases affected the catalytic performance. Moreover, EDS confirmed the formation of Pt3Sn and PtSn alloys on the catalyst surface. In terms of catalytic activity, the Pt3Sn alloy showed better performance than the PtSn alloy. Relationships between the intermetallic interactions and catalytic activity were investigated using X-ray photoelectron spectroscopy. Furthermore, qualitative analysis of coke formation was conducted after propane dehydrogenation using differential thermal analysis.

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Facile Fabrication of Nanosized Nickel Powder via Solid-State Reaction at Low Heat and its Catalytic Performance

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.393-395.1235 ◽

2011 ◽

Vol 393-395 ◽

pp. 1235-1241

Author(s):

Liu Hong ◽

Wu Bin ◽

Feng Cheng Tao ◽

Qin Xia

Keyword(s):

Catalytic Activity ◽

Solid State ◽

Solid State Reaction ◽

Photoelectron Spectroscopy ◽

Catalytic Performance ◽

X Ray ◽

Nickel Powders ◽

Transmission Electron ◽

Raney Ni ◽

Facile Fabrication

Nano-Nickel (Ni0) powders have been successfully prepared via the reduction of nanosized NiO powders by the solid state reaction. And the nanosized NiO powders were derived from low temperature (350°C) calcinations in muffle in air of nanosized Ni(OH)2 powders firstly prepared by the room temperature solid state reaction between NiSO4•6H2O and NaOH by H2 at 400°C for 4 h. The crystallinity, microstructure of surface and xps property of obtained nickel powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, the catalytic activity of the obtained nanosized Ni powders for hydrogenation of nitrobenzene to aniline was investigated. The results show that the spherical Ni parepared in particle sizes ranges from 20 to 25 nm and achieves enhanced catalytic activity for hydrogenation of nitrobenzene to aniline compared with Raney Ni.

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