scholarly journals Hydrous Hydrazine Decomposition for Hydrogen Production Using of Ir/CeO2: Effect of Reaction Parameters on the Activity

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1340
Author(s):  
Davide Motta ◽  
Ilaria Barlocco ◽  
Silvio Bellomi ◽  
Alberto Villa ◽  
Nikolaos Dimitratos

In the present work, an Ir/CeO2 catalyst was prepared by the deposition–precipitation method and tested in the decomposition of hydrazine hydrate to hydrogen, which is very important in the development of hydrogen storage materials for fuel cells. The catalyst was characterised using different techniques, i.e., X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with X-ray detector (EDX) and inductively coupled plasma—mass spectroscopy (ICP-MS). The effect of reaction conditions on the activity and selectivity of the material was evaluated in this study, modifying parameters such as temperature, the mass of the catalyst, stirring speed and concentration of base in order to find the optimal conditions of reaction, which allow performing the test in a kinetically limited regime.

Chemija ◽  
2020 ◽  
Vol 31 (1) ◽  
Author(s):  
Jolita Jablonskienė ◽  
Dijana Šimkūnaitė ◽  
Jūratė Vaičiūnienė ◽  
Algirdas Selskis ◽  
Audrius Drabavičius ◽  
...  

MnO2/C nanocomposites have been prepared using a simple onestep microwave heating method by applying different concentrations of cationic surfactant – cetyl trimethylammonium bromide (CTAB). The morphology and composition of the prepared MnO2/C nanocomposites have been investigated using X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrochemical performance of the prepared nanocomposites has been analysed using cyclic voltammetry. It was found that a high specific capacitance (Cs) of 742 F g−1 at a scan rate of 10 mV s−1 in a 1 M Na2SO4 solution has been obtained for the MnO2/C nanocomposite that has the mass loading of 0.140 mg cm−2 and has been synthesized in the absence of CTAB. Meanwhile, the application of CTAB allowed the increase in the mass loading of MnO2 in the nanocomposites. In the presence of CTAB, the highest value of 654 F g−1 at a scan rate of 10 mV s−1 has been obtained for MnO2/C that has the mass loading of 0.570 mg cm−2. This result confirmed a good performance of the prepared MnO2/C nanocomposites as the electrode material for supercapacitors.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Homa Kohzadi ◽  
Mohammad Soleiman-Beigi

AbstractIn this research, natural asphalt as a mineral carbonuous material was converted to sodium natural asphalt sulfonate (Na-NAS) and, then, was linked to Fe3O4 MNPs in order to synthesize the magnetic nanocatalyst. Afterwards, Cupper (I) and Cu (II) was grafted on Fe3O4-PTMS-NAS. Moreover, it is worth mentioning that the synthesized the novel magnetic nanocatalyst (Fe3O4-PTMS-NAS@Cu) was successfully used in Suzuki and Stille coupling reactions. The Fe3O4-PTMS-NAS@Cu MNPs were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), inductively coupled plasma (ICP), BET and X-ray photoelectron spectroscopy (XPS) analysis. Besides, sulfonation of natural asphalt, magnetization of catalyst, grafting of Cu (I) and Cu (II) to NAS and catalyst formation were investigated and proved carefully. This nanocatalyst can be comfortably separated from the reaction medium through an external magnetic field and can also be recovered and reused, while maintaining its catalytic activity.


2020 ◽  
Vol 98 (12) ◽  
pp. 771-778
Author(s):  
Xin Chang ◽  
Xiangyang Xu ◽  
Zhifeng Gao ◽  
Yingrui Tao ◽  
Yixuan Yin ◽  
...  

A nanocomposite, reduced graphene oxide (RGO) modified ZnCo2O4 (ZnCo2O4–RGO) was synthesized via one-step solvothermal method for activating persulfate (PS) to degrade bisphenol A (BPA). The morphology and structure of the nanocomposite were identified by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. RGO provides nucleation sites for ZnCo2O4 to grow and inhibits the agglomeration of the nanoparticles. The influence of different reaction conditions on the oxidation of BPA catalyzed by ZnCo2O4–RGO was investigated, including the content of RGO, the dosage of catalyst, the concentration of humic acid (HA), anions in the environment, the reaction temperature, and pH. BPA can be totally degraded within 20 min under optimized reaction conditions. The presence of HA, Cl−, and NO3− only has a slight effect on the oxidation of BPA, whereas the presence of either H2PO4− or HCO3− can greatly inhibit the reaction. ZnCo2O4–RGO shows good cycling stability and practical application potential. A reaction mechanism of the degradation of BPA was also explored.


2019 ◽  
Vol 11 (12) ◽  
pp. 1731-1738 ◽  
Author(s):  
Ma Hui ◽  
Wu Juzhen ◽  
Zhao Li ◽  
Zhou Zheng ◽  
Guo Jiahu

A one-pot simple and efficient synthetic route for the synthesis of Au-loaded Fe2O3 nanoparticles was developed, and this material's photocatalytic activity for visible light assisted oxidation of alcohols and degradation of organic dye were studied. As-synthesized nanostructured catalyst was characterised by powder X-ray diffraction (XRD), transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), SEM-mapping, X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption isotherm (BET), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). It was observed that 5–10 nm Au-nanoparticles supported on 10–80 nm Fe2O3 shows boomerang-shaped nanoparticle. Gold loading of 1 wt% shows high conversion and selectivity towards the target product aldehyde. The synthesized nanomaterial also proved to be an excellent photocatalyst for degradation of organic dyes such as methylene blue (MB) and rhodamine B (RhB). The catalyst proved to be noteworthy as it does not loss in its catalytic activity even after five cycles of reuse.


2005 ◽  
Vol 83 (8) ◽  
pp. 1093-1097 ◽  
Author(s):  
Qingrui Zhao ◽  
Xuanjun Zhang ◽  
Qing Yang ◽  
Yi Xie

A direct and simple surfactant- and template-free route has been developed for the controlled synthesis of Sb2O3 belt-like microstructures. By adjusting the reactant ratio between SbCl3 and urea under solvothermal reaction conditions, broom-like belts and rods of Sb2O3 have been successfully prepared. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS) has been used to characterize the phases and morphologies of the as-prepared products. A possible formation mechanism is also discussed.Key words: antimony trioxide, solvothermal synthesis, broom-like belts.


NANO ◽  
2021 ◽  
pp. 2150002
Author(s):  
Yalu Wu ◽  
Yinyin Xu ◽  
Jingbo Feng ◽  
Yan Zhang

The novel Al-MOF@PPy@Au nanocomposites were synthesized by an in-situ growth method. The prepared Al-MOF@PPy@Au nanocomposites were characterized by Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectrometer (FTIR), X-ray powder diffraction (XRD), Inductively Coupled Plasma (ICP) and X-ray photoelectron spectroscopy (XPS). The catalytic properties of the prepared Al-MOF@PPy@Au nanocomposites with different content of Au were investigated. The results illustrated that the Al-MOF@PPy@Au(G) with 27.80 wt.% (w/w) Au obtained good catalytic performance. P-nitrophenol (4-NP), methyl orange (MO), methylene blue (MB) and rhodamine B (RhB) were used to test the catalytic degradation of Al-MOF@PPy@Au(G) nanocomposites. The degradation efficiency of the Al-MOF@PPy@Au(G) nanocomposites for 4-NP, MO, MB and RhB reached 92.12%, 93.84%, 93.19% and 92.44% within 25 min, 7 min, 16 min and 2 min, respectively. The Al-MOF@PPy@Au(G) nanocomposites still have good degradation efficiency and good stability for 4-NP within one month being in water. The Al-MOF@PPy@Au(G) nanocomposites can be applied to the real water solution without causing the change of the degradation efficiency.


Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1258 ◽  
Author(s):  
Selvan Mohan ◽  
Juliska Princz ◽  
Banu Ormeci ◽  
Maria C. DeRosa

There is increasing interest in the environmental fate and effects of engineered nanomaterials due to their ubiquitous use in consumer products. In particular, given the mounting evidence that dramatic transformations can occur to a nanomaterial throughout its product lifecycle, the appropriateness of using pristine nanomaterials in environmental testing is being questioned. Using a combination of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-mass spectrometry (ICP-MS), this work examines the morphological and compositional effects of conditions mimicking a typical lifecycle of a nano-enabled product, from the production of the silver nanoparticle (AgNP)-laden textiles, through its use, laundering, and then finally, its leaching and incubation in the wastewater collection system. These simulated weathering conditions showed evidence for the transformation of AgNPs into AgCl and Ag2S. Incubation in raw wastewater had the most dramatic effect on the AgNPs in terms of transformation, no matter what initial weathering was applied to the NPs prior to incubation. However, despite extensive transformation noted, AgNPs were still present within all the samples after the use scenarios.


Author(s):  
Fengfeng Li ◽  
Mingxi Zhang ◽  
Jin Wang ◽  
Yongfeng Cai ◽  
Dushao Zhao ◽  
...  

Abstract In this work, we fabricate a highly efficient photocatalytic AgBr/Ag2CO3 heterojunction through the co-precipitation method. The obtained samples were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible diffuse reflectance spectra and X-ray photoelectron spectroscopy. The photocatalytic activities of obtained samples can be assessed by visible light (λ ≥ 400 nm) degradation of rhodamine B solution. X-ray diffraction revealed that the crystallinity of the AgBr/Ag2CO3heterojunction was significantly higher than pure AgBr and Ag2CO3. Moreover, the AgBr/ Ag2CO3 heterojunction prepared at pH = 6 has the best photocatalytic performance, it can raise the degradation degree of rhodamine B over 95% at 20 min. Finally, a possible photocatalytic mechanism is discussed.


Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 394 ◽  
Author(s):  
Xinling Wang ◽  
Di Zhu ◽  
Yan Zhong ◽  
Dianhui Wang ◽  
Chaohao Hu

The pyrochlore-type (Sr0.6Bi0.305)2Bi2O7 (SBO) containing Bi3+ and Bi5+ mixed valent states was first investigated as a photocatalyst in our very recent work. To further improve the photocatalytic performance, AgBr/SBO heterostructured composites were synthesized by using a deposition-precipitation method. The characterization of phase structure, morphology, microstructure, elemental composition, and optical properties of the obtained products were performed using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM)TEM, X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity of samples was evaluated by degrading methylene blue under visible light illumination. AgBr/SBO composites possess high stability and significantly enhanced photocatalytic performance. The improvement of photocatalytic activity is due to the enhanced light absorption and the separation of photoinduced electrons and holes on the interface of AgBr/SBO heterostructured composites.


Clay Minerals ◽  
2001 ◽  
Vol 36 (3) ◽  
pp. 447-464 ◽  
Author(s):  
J. M. Huggett ◽  
A. S. Gale ◽  
N. Clauer

AbstractVariegated palaeosols, which formed from weathering of clays, silts and brackish to freshwater limestones, are present in the Late Eocene–Early Oligocene Solent Group of the Hampshire Basin, southern UK. The composition and origin of the clay in three segments of the lower part of the Solent Group have been investigated by X-ray diffraction, microprobe analysis, inductively coupled plasma-mas spectrometry, K/Ar dating, high resolution scanning electron microscopy, analytical transmission electron microscopy and wet chemistry. The detrital clay mineral suite is dominated by illite and smectite with minor kaolinite and chlorite. Seasonal wetting and drying in gley soils has resulted in replacement of smectite by Fe-rich, or illite-rich illitesmectite. Illite has also formed with gypsum and calcite in ephemeral hypersaline alkaline lakes that periodically dried out. This illite may have precipitated directly from solution. X-ray diffraction data and probe analyses indicate that the neoformed illite is Fe-rich. The K and Fe for the illitization are thought to be derived from weathered glauconite reworked from the underlying Bracklesham Group and Barton Beds.


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