scholarly journals The Activation of Mg Powder Promoted by Chloride and Activation Mechanism

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1435
Author(s):  
Xiaoxuan Wang ◽  
Xiaoyan Guo ◽  
Lixiang Zhu ◽  
Shuo Wang ◽  
Meishuai Zou ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Ball Milling ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Generation ◽  
Synergistic Effects ◽  
Milling Process ◽  
Production Performance ◽  
Activation Mechanism ◽  
X Ray ◽  
Highly Active

Magnesium has bright market prospects such as generating thrust for under water engines and hydrogen production. However, the passive oxide film on the surface of magnesium powder prevents the further reaction of magnesium with water at room temperature. In this paper, highly active magnesium-based materials were prepared via ball milling pure Mg with different chlorides (NiCl2, CoCl2, CuCl2, FeCl3). The activity of the as obtained powder was analyzed through Scanning Electron Microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), synchrotron X-ray tomography, Extended X-ray Absorption Fine Structure (EXAFS), etc. Among the various compositions, the Mg-6%CoCl2 composite exhibited the best hydrogen production performance with a hydrogen generation volume of 423 mL/(0.5 g) and a conversion yield of 96.6%. The related activation mechanism was thoroughly studied, showing that the addition of chloride during ball milling can effectively break the continuity of oxide films on Mg surfaces and introduces a large number of micro defects. In addition, the EXAFS and tomography data verified that metallic cobalt was generated during the ball milling process, subsequently forming a Mg-Co micro glance cell, and the Cl− in the system accelerates the corrosion of Mg. The active mechanism can be verified as synergistic effects of micro glance cell and as-generated surface microcracks.

TPPH/g-C3N4 Nanohybrids Constructed with Surfactant-Assisted Co-assembly for Photocatalytic Hydrogen Generation

NANO ◽  
2021 ◽  
Author(s):  
Ye Shang ◽  
Manfei Lv ◽  
Songtian Li
Keyword(s):  
Hydrogen Production ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Generation ◽  
Separation Efficiency ◽  
Electrochemical Impedance ◽  
Production Capacity ◽  
Noncovalent Interaction ◽  
Full Spectrum ◽  
X Ray ◽  
Photocatalytic Hydrogen Generation

A new type of pure organic 5,10,15,20-tetra (4-hydroxyphenyl) porphyrin (TPPH)/[Formula: see text]-C3N4 nanohybrid was prepared to expand the light absorption range of graphitic carbon nitride materials. The morphology and structure of the composites were systematically characterized by scanning electron microscope, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Results show that after the introduction of TPPH, the visible light area optical absorption of the composite sample increased significantly under the noncovalent interaction of TPPH and [Formula: see text]-C3N4, and the electrochemical impedance spectroscopy and [Formula: see text]–[Formula: see text] measurements confirmed the improved charge separation efficiency of the sample and showed excellent photocatalytic hydrogen production capacity. Under full spectrum irradiation, the hydrogen production of 1.67% TPPH/[Formula: see text]-C3N4 without adding co-catalyst reached 10.87[Formula: see text]mmol[Formula: see text][Formula: see text], about 2.68 times that of pure [Formula: see text]-C3N4 (4.06[Formula: see text]mmol[Formula: see text][Formula: see text]), which showed effective promotion of the electron transfer between TPPH and [Formula: see text]-C3N4.

scholarly journals Photoreduction of a Pd-Doped Mesoporous TiO2 Photocatalyst for Hydrogen Production under Visible Light

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 74 ◽  
Author(s):  
Bianca Rusinque ◽  
Salvador Escobedo ◽  
Hugo de Lasa
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Morphological Characteristics ◽  
Production Performance ◽  
Bet Surface Area ◽  
Tio2 Photocatalyst ◽  
X Ray ◽  
Production Of Hydrogen

Photoreduction with visible light can enhance the photocatalytic activity of TiO2 for the production of hydrogen. In this article, we present a strategy to photoreduce a palladium-doped TiO2 photocatalyst by using near-UV light prior to its utilization. A sol-gel methodology was employed to prepare the photocatalysts with different metal loadings (0.25–5.00 wt% Pd). The structural and morphological characteristics of the synthesized Pd-TiO2 were analyzed by using X-ray Diffraction (XRD), BET Surface Area (SBET), TemperatureProgrammed Reduction (TPR), Chemisorption and X-ray Photoelectron Spectroscopy (XPS). Hydrogen was produced by water splitting under visible light irradiation using ethanol as an organic scavenger. Experiments were developed in the Photo-CREC Water-II (PCW-II) Reactor designed at the CREC-UWO (Chemical Reactor Engineering Centre). It was shown that the mesoporous 0.25 wt% Pd-TiO2 with 2.5 1eV band gap exhibits, under visible light, the best hydrogen production performance, with a 1.58% Quantum Yield being achieved.

Study on Al-Li3AlH6-CaO Composite for Hydrogen Production Performance

2016 ◽  
Vol 852 ◽  
pp. 841-847
Author(s):  
Xiang Fei Zhang ◽  
Fen Xu ◽  
Li Xian Sun ◽  
Fang Yu ◽  
Chong Zhao
Keyword(s):  
Hydrogen Production ◽  
Ball Milling ◽  
Hydrogen Generation ◽  
Production Performance ◽  
Hydrogen Yield ◽  
Practical Application ◽  
Corrosion Resistant ◽  
The Poor ◽  
Stability Limits ◽  
Poor Stability

The Al-Li3AlH6 composite as a promising hydrogen production material has attracted increasing attention. However, the poor stability limits practical application. In this paper, the Al-Li3AlH6-CaO composite has been synthesized by ball milling. The results show that the increase of the amount of added CaO can enhance the rate of the hydrogen generation. The rate of the hydrogen generation reaches 40.1 % when the amount of added CaO is 30 wt%, which is due to the fact that the added CaO can destroys the Al2O3 films. The influence of amount of added CaO on the corrosion resistant of the Al-Li3AlH6-CaO is also investigated. The Al-Li3AlH6-CaO with 35 wt% CaO exhibits well corrosion resistant performance, and the hydrogen yield decreases by 22.65 % in 30 days, while the hydrogen yield of the Al-Li3AlH6-CaO without CaO drops by 45.4% in 5 days.

Highly active carbon nanotube–promoted Rh-Mn-Li/SiO2 catalysts for the synthesis of C2+ oxygenates from syngas

2021 ◽  
pp. 174751982098472
Author(s):  
Jun Yu ◽  
Ying Han ◽  
Guoqing Chen ◽  
Xiuzhen Xiao ◽  
Haifang Mao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Co Hydrogenation ◽  
X Ray ◽  
Highly Active ◽  
Transmission Electron ◽  
Co Insertion ◽  
Temperature Programmed Surface Reaction ◽  
Temperature Programmed ◽  
Oxygenate Synthesis

The effect of carbon nanotubes on the catalytic properties of Rh-Mn-Li/SiO2 catalysts was investigated for CO hydrogenation. The catalysts were comprehensively characterized by means of X-ray power diffraction, N2 sorption, transmission electron microscope, H2–temperature-programmed reduction, CO–temperature-programmed desorption, temperature-programmed surface reaction, and X-ray photoelectron spectroscopy. The results showed that an appropriate amount of carbon nanotubes can be attached to the surface of the SiO2 sphere and can improve the Rh dispersion. Moderate Rh-Mn interaction can be obtained by doping with the appropriate amount of carbon nanotubes, which promotes the formation of strongly adsorbed CO and facilitates the progress of CO insertion, resulting in the increase in the selectivity of C2+ oxygenate synthesis.

scholarly journals Green Synthesis of Feather-Shaped MoS2/CdS Photocatalyst for Effective Hydrogen Production

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Yang Liu ◽  
Hongtao Yu ◽  
Xie Quan ◽  
Shuo Chen
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Production ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Sulfur Source ◽  
X Ray ◽  
Transmission Electron ◽  
Microscopy Images ◽  
Effective Hydrogen ◽  
Better Than

MoS2/CdS photocatalyst was fabricated by a hydrothermal method for H2production under visible light. This method used low toxic thiourea as a sulfur source and was carried out at 200°C. Thus, it was better than the traditional methods, which are based on an annealing process at relatively high temperature (above 400°C) using toxic H2S as reducing agent. Scanning electron microscopy and transmission electron microscopy images showed that the morphologies of MoS2/CdS samples were feather shaped and MoS2layer was on the surface of CdS. The X-ray photoelectron spectroscopy testified that the sample was composed of stoichiometric MoS2and CdS. The UV-vis diffuse reflectance spectra displayed that the loading of MoS2can enhance the optical absorption of MoS2/CdS. The photocatalytic activity of MoS2/CdS was evaluated by producing hydrogen. The hydrogen production rate on MoS2/CdS reached 192 μmol·h−1. This performance was stable during three repeated photocatalytic processes.

Structural Evaluation of Ti-22.2Si-11.1B Powders Milled with PCA Addition

2008 ◽  
Vol 591-593 ◽  
pp. 147-153
Author(s):  
Gilbert Silva ◽  
Erika Coaglia Trindade Ramos ◽  
N.S. da Silva ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Electron Microscopy ◽  
Ball Milling ◽  
Ball Mill ◽  
Milling Process ◽  
Argon Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Evaluation ◽  
Equilibrium Structures ◽  
Scanning Electron

A large amount of the Ti6Si2B compound can be formed by mechanical alloying and subsequent heat treatment from the elemental Ti-22.2at%Si-11.1at%B powder mixture, but the yield powder after ball milling is reduced due to an excessive agglomeration of ductile particles on the balls and vial surfaces. This work reports on the structural evaluation of Ti-22.2at%Si-11.1at%B powders milled with PCA addition, varying its amount between 1 and 2 wt-%. The milling process was carried out in a planetary ball mill under argon atmosphere, and the milled powders were then heated at 1200oC for 1h under Ar atmosphere in order to obtain equilibrium structures. Samples were characterized by X-ray diffraction, scanning electron microscopy, and thermal analysis. Results revealed that the PCA addition reduced the excessive agglomeration during the ball milling of Ti-22.2at-%Si-11.1at-%B powders. After heating at 1200oC for 1h, the Ti5Si3, Ti3O and/or Ti2C phases were preferentially formed in Ti-22.2at%Si-11.1at%B powders milled with PCA addition, and the Ti6Si2B formation was inhibited.

Amorphous Ni-Co-B Catalyst for Hydrolysis of NaBH4 in Alkaline Solution

2011 ◽  
Vol 675-677 ◽  
pp. 33-36
Author(s):  
Chuan Wu ◽  
Ying Bai ◽  
Feng Wu ◽  
Dan Xian Liu
Keyword(s):  
Alkaline Solution ◽  
Photoelectron Spectroscopy ◽  
Proton Exchange Membrane ◽  
Hydrogen Generation ◽  
Chemical Reduction ◽  
Heat Treating ◽  
Proton Exchange ◽  
X Ray ◽  
Bet Analysis ◽  
Exchange Membrane

Amorphous Ni-Co-B catalyst was synthesized by a chemical reduction method, and followed by a heat-treating at 100°C, then characterized by X-ray diffraction (XRD), Scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmetr-Teller (BET) analysis, and adopted to help accelerating hydrolysis reaction of NaBH4 alkaline solution. It is proved that the amorphous Ni-Co-B catalyst is not a simple combination of elemental Ni, Co and B, but a multiplex metal boride. It exhibits an maximum hydrogen generation rate of 210 ml/min/(g catalyst) at 100% H2 utilization, which is potentially to give a successive H2 supply for proton exchange membrane fuel cells.

scholarly journals Effect of Organic Assistant on the Performance of Ceria-Based Catalysts for the Selective Catalytic Reduction of NO with Ammonia

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 357 ◽  
Author(s):  
Huang ◽  
Li ◽  
Qiu ◽  
Chen ◽  
Cheng ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Ball Milling ◽  
Catalytic Reduction ◽  
Temperature Programmed Desorption ◽  
Milling Process ◽  
X Ray ◽  
Ball Milling Process ◽  
Nh3 Scr ◽  
Temperature Programmed ◽  
Catalytic Performances

In the present study, a series of CeO2/TiO2 catalysts were fabricated by dry ball milling method in the absence and presence of organic assistants, and their catalytic performances for the selective catalytic reduction (SCR) of NO by NH3 were investigated. It was found that the addition of organic assistants in the ball milling process and the calcining ambience exerted a significant influence on the catalytic performances of CeO2/TiO2 catalysts. The nitrogen sorption isotherm measurement (BET), powder X-ray diffraction (XRD), Raman spectra, high-resolution transmission electron microscopy (HR-TEM), hydrogen temperature-programmed reduction (H2-TPR), ammonia temperature-programmed desorption (NH3-TPD), sulfur dioxide temperature-programmed desorption (SO2-TPD), thermogravimetric analysis (TG), Fourier transform infrared (FT-IR) and X-ray photoelectron spectra (XPS) characterizations showed that the introduction of citric acid in the ball milling process could significantly change the decomposition process of the precursor mixture, which can lead to improved dispersion and reducibility of cerium species, surface acidity as well as the surface microstructure, all which were responsible for the high low temperature activity of CeTi-C-N in an NH3-SCR reaction. In contrast, the addition of sucrose in the milling process showed an inhibitory effect on the catalytic performance of CeO2/TiO2 catalyst in an NH3-SCR reaction, possibly due to the decrease of the crystallinity of the TiO2 support and the carbon residue covering the active sites.

CoO-Co2P composite nanosheets as highly active catalysts for sodium borohydride hydrolysis to generate hydrogen

2020 ◽  
Vol 13 (06) ◽  
pp. 2051025
Author(s):  
Hongyan Liu ◽  
Qianyu Shi ◽  
Yumei Yang ◽  
Ya-Na Yu ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Sodium Borohydride ◽  
Hydrogen Generation ◽  
Sodium Hypophosphite ◽  
X Ray Diffraction ◽  
Water Displacement ◽  
X Ray ◽  
Highly Active ◽  
Naoh Solution ◽  
Adsorption Desorption ◽  
Hydrolysis Of

In this paper, CoO[Formula: see text]Co2P composite nanocatalysts as highly active catalysts were successfully prepared for catalytic hydrolysis of sodium borohydride (NaBH[Formula: see text] to generate hydrogen. For catalyst preparation, pre-synthesized Co(OH)2 nanosheets were uniformly mixed with sodium hypophosphite (NaH2PO[Formula: see text] and then treated through vapor-phase phosphorization process. For characterization, field-emission scanning electron microscopy (FE-SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), N2 adsorption–desorption measurement and X-ray photoelectric spectroscopy (XPS) were carried out, and traditional water-displacement method was performed to measure the hydrogen generation rate (HGR). It was found that component and catalytic activity of the composites were greatly affected by the ratio of Co(OH)2 to NaH2PO2. When the ratio was 2:1, the obtained catalyst composed of CoO and Co2P presented the highest HGR up to 3.94[Formula: see text]L min[Formula: see text] g[Formula: see text] using a 2[Formula: see text]wt.% NaBH[Formula: see text][Formula: see text]wt.% NaOH solution at [Formula: see text]C, and the apparent activation energy was detected as low as 27.4[Formula: see text]kJ mol[Formula: see text]. Additionally, the optimum CoO[Formula: see text]Co2P catalyst still retains 60% of the initial activity after recycling four times.

scholarly journals Characterization and x-ray absorption spectroscopy of ilmenite nanoparticles derived from natural ilmenite ore via acid-assisted mechanical ball-milling process

2017 ◽  
Vol 8 (3) ◽  
pp. 035012 ◽  
Author(s):  
Weerachon Phoohinkong ◽  
Sorapong Pavasupree ◽  
Anucha Wannagon ◽  
Samunya Sanguanpak ◽  
Kanokthip Boonyarattanakalin ◽  
...  
Keyword(s):  
Ball Milling ◽  
Absorption Spectroscopy ◽  
Milling Process ◽  
X Ray ◽  
Ball Milling Process ◽  
X Ray Absorption ◽  
Mechanical Ball Milling
Sign in / Sign up

Export Citation Format

Share Document