scholarly journals LP-UV-Nano MgO2 Pretreated Catalysis Followed by Small Bioreactor Platform Capsules Treatment for Superior Kinetic Degradation Performance of 17α-Ethynylestradiol

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 83 ◽  
Author(s):  
Lakshmi Prasanna Vaddadi ◽  
Dror Avisar ◽  
Vinod Kumar Vadivel ◽  
Ofir Menashe ◽  
Eyal Kurzbaum ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Degradation Mechanism ◽  
Complete Removal ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wet Chemical Synthesis ◽  
Magnesium Peroxide ◽  
Uv Dose

A successful attempt to degrade synthetic estrogen 17α-ethynylestradiol (EE2) is demonstrated via combining photocatalysis employing magnesium peroxide (MgO2)/low-pressure ultraviolet (LP-UV) treatment followed by biological treatment using small bioreactor platform (SBP) capsules. Reusable MgO2 was synthesized through wet chemical synthesis and extensively characterized by X-ray diffraction (XRD) for phase confirmation, X-ray photoelectron spectroscopy (XPS) for elemental composition, Brunauer-Emmett-Teller (BET) to explain a specific surface area, scanning electron microscopy (SEM) imaging surface morphology, and UV-visible (Vis) spectrophotometry. The degradation mechanism of EE2 by MgO2/LP-UV consisted of LP-UV photolysis of H2O2 in situ (produced by the catalyst under ambient conditions) to generate hydroxyl radicals, and the degradation extent depended on both MgO2 and UV dose. Moreover, the catalyst was successfully reusable for the removal of EE2. Photocatalytic treatment by MgO2 alone required 60 min (~1700 mJ/cm2) to remove 99% of the EE2, whereas biodegradation by SBP capsules alone required 24 h to remove 86% of the EE2, and complete removal was not reached. The sequential treatment of photocatalysis and SBP biodegradation to achieve complete removal required only 25 min of UV (~700 mJ/cm2) and 4 h of biodegradation (instead of >24 h). The combination of UV photocatalysis and biodegradation produced a greater level of EE2 degradation at a lower LP-UV dose and at less biodegradation time than either treatment used separately, proving that synergetic photocatalysis and biodegradation are effective treatments for degrading EE2.

A reaction cell for time-resolvedin situXAS studies during wet chemical synthesis: the Cu2(OH)3Cl case

2013 ◽  
Vol 21 (1) ◽  
pp. 254-258 ◽  
Author(s):  
Jocenir Boita ◽  
Maria do Carmo Martins Alves ◽  
Jonder Morais
Keyword(s):  
Chemical Synthesis ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Reaction Cell ◽  
Time Resolved ◽  
X Ray ◽  
Wet Chemical Synthesis ◽  
X Ray Absorption ◽  
Electronic And Structural Properties

The use ofin situtime-resolved dispersive X-ray absorption spectroscopy (DXAS) to monitor the formation of Cu2(OH)3Cl particles in an aqueous solution is reported. The measurements were performed using a dedicated reaction cell, which enabled the evolution of the CuK-edge X-ray absorption near-edge spectroscopy to be followed during mild chemical synthesis. The formed Cu2(OH)3Cl particles were also characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. The influence of polyvinylpyrrolidone (PVP) on the electronic and structural properties of the formed particles was investigated. The results indicate clearly the formation of Cu2(OH)3Cl, with or without the use of PVP, which presents very similar crystalline structures in the long-range order. However, depending on the reaction, dramatic differences were observed byin situDXAS in the vicinities of the Cu atoms.

scholarly journals “PdO vs. PtO”—The Influence of PGM Oxide Promotion of Co3O4 Spinel on Direct NO Decomposition Activity

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 62 ◽  
Author(s):  
Gunugunuri K. Reddy ◽  
Torin C. Peck ◽  
Charles A. Roberts
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Decomposition ◽  
Single Element ◽  
X Ray Diffraction ◽  
X Ray ◽  
Promotional Effect ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Thermal Stability Of

Direct decomposition of NO into N2 and O2 (2NO→N2 + O2) is recognized as the “ideal” reaction for NOx removal because it needs no reductant. It was reported that the spinel Co3O4 is one of the most active single-element oxide catalysts for NO decomposition at higher reaction temperatures, however, activity remains low below 650 °C. The present study aims to investigate new promoters for Co3O4, specifically PdO vs. PtO. Interestingly, the PdO promoter effect on Co3O4 was much greater than the PtO effect, yielding a 4 times higher activity for direct NO decomposition at 650 °C. Also, Co3O4 catalysts with the PdO promoter exhibit higher selectivity to N2 compared to PtO/Co3O4 catalysts. Several characterization measurements, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR), and in situ FT-IR, were performed to understand the effect of PdO vs. PtO on the properties of Co3O4. Structural and surface analysis measurements show that impregnation of PdO on Co3O4 leads to a greater ease of reduction of the catalysts and an increased thermal stability of surface adsorbed NOx species, which contribute to promotion of direct NO decomposition activity. In contrast, rather than remaining solely as a surface species, PtO enters the Co3O4 structure, and it promotes neither redox properties nor NO adsorption properties of Co3O4, resulting in a diminished promotional effect compared to PdO.

A dispenser–reactor apparatus applied forin situXAS monitoring of Pt nanoparticle formation

2015 ◽  
Vol 22 (3) ◽  
pp. 736-744 ◽  
Author(s):  
Jocenir Boita ◽  
Marcus Vinicius Castegnaro ◽  
Maria do Carmo Martins Alves ◽  
Jonder Morais
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metallic Nanoparticles ◽  
Pt Nanoparticles ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Two Stages ◽  
X Ray Absorption

In situtime-resolved X-ray absorption spectroscopy (XAS) measurements collected at the PtL3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser–reactor apparatus allowed for monitoring changes in the XAS spectra from the earliest moments of Pt ions in solution until the formation of metallic nanoparticles with a mean diameter of 4.9 ± 1.1 nm. By monitoring the changes in the local chemical environment of the Pt atoms in real time, it was possible to observe that the NPs formation kinetics involved two stages: a reduction-nucleation burst followed by a slow growth and stabilization of NPs. Subsequently, the synthesized Pt NPs were supported on activated carbon and characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The supported Pt NPs remained in the metallic chemical state and with a reduced size, presenting slight lattice parameter contraction in comparison with the bulk Pt values.

Surface nitridation of Ta powder by molten-salt electrolysis of Ta2O5 under N2 atmosphere

2020 ◽  
Vol 13 (07) ◽  
pp. 2050032
Author(s):  
Qing Huang ◽  
Guojin Zheng ◽  
Tian Wu
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Cell Voltage ◽  
X Ray Diffraction ◽  
Molten Salt Electrolysis ◽  
X Ray ◽  
Structured Catalysts ◽  
Transmission Electron ◽  
N2 Atmosphere

The electro-deoxidation of Ta2O5 in molten CaCl2 under N2 atmosphere is a facile way for the in situ surface nitridation of Ta particles. The cell voltage and electrolysis time of Ta2O5 are rationalized to realize the in situ surface nitridation of Ta. All the characterization results including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and elements mapping as well as X-ray photoelectron spectroscopy (XPS) confirm the formation of Ta2N layers on the surface of Ta particles, with the thickness of 3–4[Formula: see text]nm. This method provides a strategy for the facile in situ surface nitridation with N2 as the nitrogen source for the fabrication of core-shell structured catalysts.

Effect of HCl+LiF Etching Process on Electrochemical Performance of Ti3C2

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050058
Author(s):  
Yuhua Huang ◽  
Weiwei Li ◽  
Bingchu Mei ◽  
Yu Yang ◽  
Zuodong Liu
Keyword(s):  
Electrochemical Performance ◽  
Photoelectron Spectroscopy ◽  
Lithium Fluoride ◽  
Specific Capacity ◽  
Etching Process ◽  
X Ray Diffraction ◽  
In Situ Oxidation ◽  
X Ray ◽  
Scanning Electron

In this paper, the effects of etching temperature and concentrations of hydrochloric acid (HCl) on the exfoliating process and the electrochemical performance of LIBs were systematically explored. The transformation from Ti3AlC2 to Ti3C2 was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectra. The suitable conditions of preparing Ti3C2 MXene though HCl and lithium fluoride (LiF) were obtained. Besides, the in-situ oxidation conditions of Ti3C2 during the etching process were studied. The TiO2/Ti3C2 was beneficial to improve the specific capacity from 125[Formula: see text]mAh[Formula: see text]g[Formula: see text] to 150[Formula: see text]mAh[Formula: see text]g[Formula: see text] at 1 C.

scholarly journals In-situ X-ray techniques for non-noble electrocatalysts

2020 ◽  
Vol 92 (5) ◽  
pp. 733-749 ◽  
Author(s):  
Sung-Fu Hung
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Mechanism ◽  
Structural Evolution ◽  
Reduction Reaction ◽  
High Price ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Techniques ◽  
State Variation

AbstractElectrocatalysis offers an alternative solution for the energy crisis because it lowers the activation energy of reaction to produce economic fuels more accessible. Non-noble electrocatalysts have shown their capabilities to practical catalytic applications as compared to noble ones, whose scarcity and high price limit the development. However, the puzzling catalytic processes in non-noble electrocatalysts hinder their advancement. In-situ techniques allow us to unveil the mystery of electrocatalysis and boost the catalytic performances. Recently, various in-situ X-ray techniques have been rapidly developed, so that the whole picture of electrocatalysis becomes clear and explicit. In this review, the in-situ X-ray techniques exploring the structural evolution and chemical-state variation during electrocatalysis are summarized for mainly oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and carbon dioxide reduction reaction (CO2RR). These approaches include X-ray Absorption Spectroscopy (XAS), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The information seized from these in-situ X-ray techniques can effectively decipher the electrocatalysis and thus provide promising strategies for advancing the electrocatalysts. It is expected that this review could be conducive to understanding these in-situ X-ray approaches and, accordingly, the catalytic mechanism to better the electrocatalysis.

CO2 utilization by dry reforming of CH4 over mesoporous Ni/KIT-6 catalyst

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Congming Tang ◽  
Juan Huang ◽  
Dong Zhang ◽  
Qingqing Jiang ◽  
Guilin Zhou
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photoelectron Spectroscopy ◽  
Pore Diameter ◽  
Co2 Utilization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Performances

Abstract The mesoporous Ni/KIT-6 catalysts with different composition were prepared by altering reduction temperatures. In addition, their physicochemical properties were characterized by X-ray diffraction, in-situ X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller techniques. The results shown that the specific surface area, composition and metallic Ni crystallinity of the Ni/KIT-6 catalyst were significantly affected by reduction temperatures. The catalytic performances of the prepared Ni/KIT-6 catalysts were evaluated via the CO2 reforming of CH4 into syngas and followed the order: RT0 < RT250 < RT300 < RT350 < RT400 < RT450 ≈ RT500. The specific surface area, pore volume, pore diameter, and Ni0 content of the most representative RT450 catalyst among of them were 646.7 m2 g−1, 0.92 cm3 g−1, 6.5 nm, and 30.9%, respectively. The CH4 and CO2 conversions of RT450 catalyst reached to 69.0 and 39.4% under a reaction temperature of 600 °C, respectively. The CO selectivity was greater than 49% and the RT450 catalyst had good stability.

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