scholarly journals Cu@Pd/C with Controllable Pd Dispersion as a Highly Efficient Catalyst for Hydrogen Evolution from Ammonia Borane

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1850
Author(s):  
Yanliang Yang ◽  
Ying Duan ◽  
Dongsheng Deng ◽  
Dongmi Li ◽  
Dong Sui ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Reduction Process ◽  
Ammonia Borane ◽  
Dark Field ◽  
Impregnation Method ◽  
Efficient Catalyst ◽  
X Ray ◽  
Transmission Electron

A series of Cu@Pd/C with different Pd contents was prepared using the galvanic reduction method to disperse Pd on the surface of Cu nanoparticles on Cu/C. The dispersion of Pd was regulated by the Cu(I) on the surface, which was introduced by pulse oxidation. The Cu2O did not react during the galvanic reduction process and restricted the Pd atoms to a specific area. The pulse oxidation method was demonstrated to be an effective process to control the oxidization degree of Cu on Cu/C and then to govern the dispersion of Pd. The catalysts were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscope (HRTEM), high angular annular dark field scanning TEM (HAADF-STEM), energy-dispersive spectroscopy (EDS) mapping, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), auger electron spectroscopy (AES), and inductively coupled plasma optical emission spectrometer (ICP-OES), which were used to catalyze the hydrogen evolution from ammonia borane. The Cu@Pd/C had much higher activity than the PdCu/C, which was prepared by the impregnation method. The TOF increased as the Cu2O in Cu/C used for the preparation of Cu@Pd/C increased, and the maximum TOF was 465 molH2 min−1 molPd−1 at 298 K on [email protected]/C-640 (0.5 wt % of Pd, 640 mL of air was pulsed during the preparation of Cu/C-640). The activity could be maintained in five continuous processes, showing the strong stability of the catalysts.

A Facile Strategy to Fabricate Nanoscale Zero-Valent Iron Decorated Graphene Oxide Composite for Dechloridation of Trichloroacetic Acid in Water

2018 ◽  
Vol 18 (12) ◽  
pp. 8252-8257 ◽  
Author(s):  
Huixuan Zhang ◽  
Xinyi Zhang ◽  
Ruonan Guo ◽  
Qingfeng Cheng ◽  
Xiuwen Cheng
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Sewage Treatment ◽  
Reduction Process ◽  
Zero Valent Iron ◽  
Chlorinated Organic Compounds ◽  
X Ray ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Adsorption Desorption

In this study, nanoscale zero-valent iron decorated graphene oxide (NZVI/GO) composite was fabricated through a reduction process in the presence of sodium borohydride (NaBH4) solution. Subsequently, physicochemical properties of the NZVI/GO composites were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy (FT-IR) and Raman spectra. Results indicated that Fe species existed in the form of Fe0, which uniformly dispersed on the surface of GO. Furthermore, the performance of NZVI/GO was evaluated by the degradation of tichloroacetic acid (TCAA). TCAA can be rapidly degraded by NZVI/GO. This paper provides a promising strategy to synthesize versatile catalyst which would be potentially applied in sewage treatment to degrade chlorinated organic compounds.

scholarly journals Amorphous Ni x Co y P-supported TiO2 nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

2019 ◽  
Vol 10 ◽  
pp. 62-70 ◽  
Author(s):  
Yong Li ◽  
Peng Yang ◽  
Bin Wang ◽  
Zhongqing Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Nanotube Arrays ◽  
Active Surface Area ◽  
X Ray ◽  
Transmission Electron

Bimetallic phosphides have been attracting increasing attention due to their synergistic effect for improving the hydrogen evolution reaction as compared to monometallic phosphides. In this work, NiCoP modified hybrid electrodes were fabricated by a one-step electrodeposition process with TiO2 nanotube arrays (TNAs) as a carrier. X-ray diffraction, transmission electron microscopy, UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy and scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy were used to characterize the physiochemical properties of the samples. The electrochemical performance was investigated by cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy. We show that after incorporating Co into Ni–P, the resulting Ni x Co y P/TNAs present enhanced electrocatalytic activity due to the improved electron transfer and increased electrochemically active surface area (ECSA). In 0.5 mol L−1 H2SO4 electrolyte, the Ni x Co y P/TNAs (x = 3.84, y = 0.78) demonstrated an ECSA value of 52.1 mF cm−2, which is 3.8 times that of Ni–P/TNAs (13.7 mF cm−2). In a two-electrode system with a Pt sheet as the anode, the Ni x Co y P/TNAs presented a bath voltage of 1.92 V at 100 mA cm−2, which is an improvment of 79% over that of 1.07 V at 10 mA cm−2.

scholarly journals Synthesis of nickel/gallium nanoalloys using a dual-source approach in 1-alkyl-3-methylimidazole ionic liquids

2019 ◽  
Vol 10 ◽  
pp. 1754-1767
Author(s):  
Ilka Simon ◽  
Julius Hornung ◽  
Juri Barthel ◽  
Jörg Thomas ◽  
Maik Finze ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Dark Field ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Dual Source ◽  
Induced Decomposition

NiGa is a catalyst for the semihydrogenation of alkynes. Here we show the influence of different dispersion times before microwave-induced decomposition of the precursors on the phase purity, as well as the influence of the time of microwave-induced decomposition on the crystallinity of the NiGa nanoparticles. Microwave-induced co-decomposition of all-hydrocarbon precursors [Ni(COD)2] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in the ionic liquid [BMIm][NTf2] selectively yields small intermetallic Ni/Ga nanocrystals of 5 ± 1 nm as derived from transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and supported by energy-dispersive X-ray spectrometry (EDX), selected-area energy diffraction (SAED) and X-ray photoelectron spectroscopy (XPS). NiGa@[BMIm][NTf2] catalyze the semihydrogenation of 4-octyne to 4-octene with 100% selectivity towards (E)-4-octene over five runs, but with poor conversion values. IL-free, precipitated NiGa nanoparticles achieve conversion values of over 90% and selectivity of 100% towards alkene over three runs.

Au NPs Loaded Al-MOF@PPy as Excellent Catalyst for the Removal of Organic Pollutants from Water

NANO ◽  
2021 ◽  
pp. 2150002
Author(s):  
Yalu Wu ◽  
Yinyin Xu ◽  
Jingbo Feng ◽  
Yan Zhang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Water Solution ◽  
Catalytic Performance ◽  
Degradation Efficiency ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Growth Method ◽  
Infrared Spectrometer

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.

scholarly journals Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4631 ◽  
Author(s):  
Juan Aliaga ◽  
Pablo Vera ◽  
Juan Araya ◽  
Luis Ballesteros ◽  
Julio Urzúa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Charge Transfer Resistance ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
Transfer Resistance ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

In this research, we report a simple hydrothermal synthesis to prepare rhenium (Re)- doped MoS2 flower-like microspheres and the tuning of their structural, electronic, and electrocatalytic properties by modulating the insertion of Re. The obtained compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Structural, morphological, and chemical analyses confirmed the synthesis of poorly crystalline Re-doped MoS2 flower-like microspheres composed of few stacked layers. They exhibit enhanced hydrogen evolution reaction (HER) performance with low overpotential of 210 mV at current density of 10 mA/cm2, with a small Tafel slope of 78 mV/dec. The enhanced catalytic HER performance can be ascribed to activation of MoS2 basal planes and by reduction in charge transfer resistance during HER upon doping.

scholarly journals Morphological Transformation of Silver Nanoparticles from Commercial Products: Modeling from Product Incorporation, Weathering through Use Scenarios, and Leaching into Wastewater

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1258 ◽  
Author(s):  
Selvan Mohan ◽  
Juliska Princz ◽  
Banu Ormeci ◽  
Maria C. DeRosa
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Environmental Fate ◽  
Consumer Products ◽  
Morphological Transformation ◽  
Environmental Testing ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Plasma Mass Spectrometry

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.

scholarly journals A Facile and Waste-Free Strategy to Fabricate Pt-C/TiO2Microspheres: Enhanced Photocatalytic Performance for Hydrogen Evolution

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hui Li ◽  
Xiaoyan Zhang ◽  
Xiaoli Cui
Keyword(s):  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Generation ◽  
Synthesis Method ◽  
Diffraction Field ◽  
Light Illumination ◽  
Thermal Synthesis ◽  
X Ray ◽  
Photocatalytic Hydrogen Generation ◽  
Transmission Electron

A facile and waste-free flame thermal synthesis method was developed for preparing Pt modified C/TiO2microspheres (Pt-C/TiO2). The photocatalysts were characterized with X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope, ultraviolet-visible (UV-vis) diffuse reflectance spectra, X-ray photoelectron spectroscopy, and thermogravimetry analysis. The photocatalytic activity was evaluated by hydrogen evolution from water splitting under UV-vis light illumination. Benefitting from the electron-hole separation behavior and reduced overpotential of H+/H2, remarkably enhanced hydrogen production was demonstrated and the photocatalytic hydrogen generation from 0.4 wt% Pt-C/TiO2increased by 22 times. This study also demonstrates that the novel and facile method is highly attractive, due to its easy operation, requiring no post treatment and energy-saving features.

scholarly journals Comparative Study of the Photocatalytic Hydrogen Evolution over Cd1−xMnxS and CdS-β-Mn3O4-MnOOH Photocatalysts under Visible Light

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 355
Author(s):  
Ksenia O. Potapenko ◽  
Anna Yu. Kurenkova ◽  
Andrey V. Bukhtiyarov ◽  
Evgeny Yu. Gerasimov ◽  
Svetlana V. Cherepanova ◽  
...  
Keyword(s):  
Solid Solution ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Manganese Salts

A series of solid solutions of cadmium and manganese sulfides, Cd1−xMnxS (x = 0–0.35), and composite photocatalysts, CdS-β-Mn3O4-MnOOH, were synthesized by precipitation with sodium sulfide from soluble cadmium and manganese salts with further hydrothermal treatment at 120 °C. The obtained photocatalysts were studied by the X-ray diffraction method (XRD), UV-vis diffuse reflectance spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N2 low temperature adsorption. The photocatalysts were tested in hydrogen production using a Na2S/Na2SO3 aqueous solution under visible light (λ = 450 nm). It was shown for the first time that both kinds of photocatalysts possess high activity in hydrogen evolution under visible light. The solid solution Cd0.65Mn0.35S has an enhanced photocatalytic activity due to its valence and conduction band position tuning, whereas the CdS-β-Mn3O4-MnOOH (40–60 at% Mn) samples were active due to ternary heterojunction formation. Further, the composite CdS-β-Mn3O4-MnOOH photocatalyst had much higher stability in comparison to the Cd0.65Mn0.35S solid solution. The highest activity was 600 mmol g−1 h−1, and apparent quantum efficiency of 2.9% (λ = 450 nm) was possessed by the sample of CdS-β-Mn3O4-MnOOH (40 at% Mn).

scholarly journals Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone

2018 ◽  
Vol 13 (1) ◽  
pp. 24
Author(s):  
Ilhem Rekkab-Hammoumraoui ◽  
Abderrahim Choukchou-Braham
Keyword(s):  
Inductively Coupled Plasma ◽  
Catalytic Properties ◽  
Optical Emission ◽  
Cobalt Nanoparticles ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Transmission Electron

A series of metal-loaded (Ru, Pt, Co) alumina catalysts were evaluated for the catalytic oxidation of cyclohexane using tertbutylhydroperoxide (TBHP) as oxidant and acetonitrile or acetic acid as solvent. These materials were prepared by the impregnation method and then characterized by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), H2 chemisorption, Fourier Transformed Infrared Spectroscopy (FTIR), High-Resolution Transmission Electron Microscopy (HRTEM), and X-ray Diffraction (XRD). All the prepared materials acted as efficient catalysts. Among them, Ru/Al2O3 was found to have the best catalytic activity with enhanced cyclohexane conversion of 36 %, selectivity to cyclohexanol and cyclohexanone of 96 % (57.6 mmol), and cyclohexane turnover frequency (TOF) of 288 h-1. Copyright © 2018 BCREC Group. All rights reservedReceived: 26th May 2017; Revised: 17th July 2017; Accepted: 18th July 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Rekkab-Hammoumraoui, I., Choukchou-Braham, A. (2018). Catalytic Properties of Alumina-Supported Ruthenium, Platinum, and Cobalt Nanoparticles towards the Oxidation of Cyclohexane to Cyclohexanol and Cyclohexanone. Bulletin of Chemical Reaction Engineering & Catalysis, 13(1): 24-36 (doi:10.9767/bcrec.13.1.1226.24-35) 

Synthesis of the rod-like NiS2@C for hydrogen evolution reaction in acidic solution

2020 ◽  
Vol 13 (02) ◽  
pp. 2050009
Author(s):  
Xiujuan Wu ◽  
Jie Wang ◽  
Fan Zhang ◽  
Junyan Gong ◽  
Pinghao Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Acidic Solution ◽  
Carbon Film ◽  
Chemical Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Onset Potential ◽  
Transmission Electron

The carbon-based NiS2 nanorods (NiS2@C) were prepared by chemical deposition and sulfidation with nickel dimethylglyoximate (Ni(DMG)2) as the starting agent. The nanorods were analyzed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy for chemical analysis. Structural characterization revealed that NiS2 existed on the surface of the rod and in the internal channels of the rod. In 0.5[Formula: see text]m H2SO4 solution, NiS2@C has lower onset potential and higher current density than NiS2. The results suggest that C improves the electrical conductivity of the NiS2 electrocatalyst, and the carbon film-based rod-like NiS2 is a more effective nanocomposite of hydrogen evolution.

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