scholarly journals Direct Observation of Ni–Mo Catalyst Formation via Thermal Reduction of Nickel Molybdate Nanorods

2020 ◽  
Author(s):  
Rituja Patil ◽  
Stephen House ◽  
Aayush Mantri ◽  
Judith C. Yang ◽  
James McKone
Keyword(s):  
Hydrogen Evolution ◽  
Thermal Reduction ◽  
Core Shell ◽  
Chemical Transformations ◽  
Nickel Molybdate ◽  
Mo Catalyst ◽  
Transmission Electron ◽  
Catalyst Formation ◽  
Exchange Membrane

Ni-Mo composites are known to catalyze several industrial relevant reactions involving hydrogen. Our interest is in Ni-Mo composites for hydrogen evolution reaction in alkaline anion exchange membrane water electrolyzers. We recently found that Ni-Mo composites comprise of core-shell structure where the core is metallic, rich in Ni while the shell is Mo-rich oxide. The transformation of the oxide intermediate into a core-shell architecture is studied in this work using <i>in situ</i> transmission electron microscopy. We reduced nickel molybdate nanorods in environmental transmission electron microscope and observed its transformation into the Ni-Mo catalyst composite. We further correlated these chemical transformations with the observed hydrogen evolution activity.

scholarly journals Direct Observation of Ni–Mo Catalyst Formation via Thermal Reduction of Nickel Molybdate Nanorods

2020 ◽  
Author(s):  
Rituja Patil ◽  
Stephen House ◽  
Aayush Mantri ◽  
Judith C. Yang ◽  
James McKone
Keyword(s):  
Hydrogen Evolution ◽  
Thermal Reduction ◽  
Core Shell ◽  
Chemical Transformations ◽  
Nickel Molybdate ◽  
Mo Catalyst ◽  
Transmission Electron ◽  
Catalyst Formation ◽  
Exchange Membrane

Ni-Mo composites are known to catalyze several industrial relevant reactions involving hydrogen. Our interest is in Ni-Mo composites for hydrogen evolution reaction in alkaline anion exchange membrane water electrolyzers. We recently found that Ni-Mo composites comprise of core-shell structure where the core is metallic, rich in Ni while the shell is Mo-rich oxide. The transformation of the oxide intermediate into a core-shell architecture is studied in this work using <i>in situ</i> transmission electron microscopy. We reduced nickel molybdate nanorods in environmental transmission electron microscope and observed its transformation into the Ni-Mo catalyst composite. We further correlated these chemical transformations with the observed hydrogen evolution activity.

Direct Observation of Ni–Mo Catalyst Formation via Thermal Reduction of Nickel Molybdate Nanorods

2020 ◽  
Author(s):  
Rituja Patil ◽  
Stephen House ◽  
Aayush Mantri ◽  
Judith C. Yang ◽  
James McKone
Keyword(s):  
Hydrogen Evolution ◽  
Thermal Reduction ◽  
Core Shell ◽  
Chemical Transformations ◽  
Nickel Molybdate ◽  
Mo Catalyst ◽  
Transmission Electron ◽  
Catalyst Formation ◽  
Exchange Membrane

Ni-Mo composites are known to catalyze several industrial relevant reactions involving hydrogen. Our interest is in Ni-Mo composites for hydrogen evolution reaction in alkaline anion exchange membrane water electrolyzers. We recently found that Ni-Mo composites comprise of core-shell structure where the core is metallic, rich in Ni while the shell is Mo-rich oxide. The transformation of the oxide intermediate into a core-shell architecture is studied in this work using <i>in situ</i> transmission electron microscopy. We reduced nickel molybdate nanorods in environmental transmission electron microscope and observed its transformation into the Ni-Mo catalyst composite. We further correlated these chemical transformations with the observed hydrogen evolution activity.

In situ construction of hydrazone-linked COF-based core–shell hetero-frameworks for enhanced photocatalytic hydrogen evolution

2020 ◽  
Vol 8 (16) ◽  
pp. 7724-7732 ◽  
Author(s):  
Yao Chen ◽  
Dong Yang ◽  
Benbing Shi ◽  
Wei Dai ◽  
Hanjie Ren ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Core Shell ◽  
Photocatalytic Hydrogen Evolution

Octahedral MOF@COF core–shell hetero-framework photocatalysts were designed which achieved superior photocatalytic H2-evolution activity.

Preparation of CuO-Decorated Core-Shell Montmorillonite-TiO2 Colloids and their Photocatalytic Activity for Hydrogen Evolution from Water

2013 ◽  
Vol 724-725 ◽  
pp. 740-743
Author(s):  
Shi Zhao Kang ◽  
Tan Wu ◽  
Xiang Qing Li ◽  
Qi Fan Wang ◽  
Jin Mu
Keyword(s):  
Photocatalytic Activity ◽  
Electron Microscope ◽  
Diffraction Analysis ◽  
Hydrogen Evolution ◽  
Uv Irradiation ◽  
Transmission Electron Microscope ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

CuO-decorated core-shell montmorillonite-TiO2 colloids were prepared and characterized with transmission electron microscope, powder X-ray diffraction analysis, Brunauer-Emmett-Teller analysis and UV-vis spectrua. Meanwhile, their photocatalytic activity for hydrogen evolution from water was explored under UV irradiation using methanol as a sacrificial reagent. The results indicate that they are an efficient photocatalyst with a rate of H2 evolution of 219 μmol·h-1·g-1 which is higher than that of anatase TiO2 nanoparticles.

In situ formed oxy/hydroxide antennas accelerating the water dissociation kinetics on a Co@N-doped carbon core–shell assembly for hydrogen production in alkaline solution

2019 ◽  
Vol 48 (31) ◽  
pp. 11927-11933 ◽  
Author(s):  
Tao Yang ◽  
Lang Pei ◽  
Shicheng Yan ◽  
Zhentao Yu ◽  
Tao Yu ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Alkaline Solution ◽  
Water Dissociation ◽  
Core Shell ◽  
Dissociation Kinetics ◽  
Alkaline Electrolytes ◽  
Carbon Core

The hydrogen evolution reaction (HER) in alkaline electrolytes is restricted severely by sluggish water dissociation in the Volmer step.

S-Scheme heterojunction based on in-situ coated core-shell NiCo2S4@WS2 photocatalyst was constructed for efficient photocatalytic hydrogen evolution

2021 ◽  
Author(s):  
Shengming Xu ◽  
Jing Xu ◽  
Linying Hu ◽  
Ye Liu ◽  
Lijun Ma
Keyword(s):  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Shell Structure ◽  
Mixed Phase ◽  
Core Shell ◽  
Photocatalytic Hydrogen Evolution ◽  
Core Shell Structure

In this paper, NiCo2S4 was coated on the surface of WS2 of 1T/2H mixed phase by two step hydrothermal method to form a in-situ core-shell structure. The unique S-Scheme heterojunction...

Core-Shell Magnesium Hydroxide/Polymermer Nanoparticles Prepared by In Situ Emulsion Copolymerization

2011 ◽  
Vol 233-235 ◽  
pp. 2125-2128
Author(s):  
Li Li Xu ◽  
Sheng Peng Liu ◽  
Xuan Li
Keyword(s):  
Magnesium Hydroxide ◽  
Chemical Structure ◽  
Hybrid Nanoparticles ◽  
Core Shell ◽  
Polymer Shell ◽  
Emulsion Copolymerization ◽  
The Core ◽  
Polymer Hybrid ◽  
Transmission Electron

In this paper, vinylated magnesium hydroxide (MH) nanosheets were prepared with 3-(trimethoxysilyl) propyl methacrylate (γ-MPS) and pristine MH nanosheets, then the MH/polymer hybrid nanoparticles were prepared by in-situ emulsion copolymerization of vinylated MH nanosheets and styrene (St) monomer and styrene/butyl acrylate (St/BA) comonomer. The morphology, thermal stability and chemical structure of the final products were investigated in detail with transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier-transform infrared spectra (FTIR). The TEM results showed that the core-shell structure of MH/Polymer nanoparticles with MH-cores and Polymer-shell was formed.

A BIO-INSPIRED POLYDOPAMINE APPROACH TO PREPARATION OF GOLD-COATED Fe3O4 CORE–SHELL NANOPARTICLES: SYNTHESIS, CHARACTERIZATION AND MECHANISM

NANO ◽  
2013 ◽  
Vol 08 (06) ◽  
pp. 1350061 ◽  
Author(s):  
PENG AN ◽  
FANG ZUO ◽  
XINHUA LI ◽  
YUANPENG WU ◽  
JUNHUA ZHANG ◽  
...  
Keyword(s):  
Shell Structure ◽  
Room Temperature ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Stabilizing Agent ◽  
X Ray ◽  
Transmission Electron ◽  
Core Shell Structure ◽  
Core Shell Nanoparticles

A biomimetic and facile approach for integrating Fe 3 O 4 and Au with polydopamine (PDA) was proposed to construct gold-coated Fe 3 O 4 nanoparticles ( Fe 3 O 4@ Au – PDA ) with a core–shell structure by coupling in situ reduction with a seed-mediated method in aqueous solution at room temperature. The morphology, structure and composition of the core–shell structured Fe 3 O 4@ Au – PDA nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The formation process of Au shell was assessed using a UV-Vis spectrophotometer. More importantly, according to investigating changes in PDA molecules by Fourier transform infrared spectroscopy (FTIR) and in preparation process of the zeta-potential data of nanoparticles, the mechanism of core–shell structure formation was proposed. Firstly, PDA-coated Fe 3 O 4 are obtained using dopamine (DA) self-polymerization to form thin and surface-adherent PDA films onto the surface of a Fe 3 O 4 "core". Then, Au seeds are attached on the surface of PDA-coated Fe 3 O 4 via electrostatic interaction in order to serve as nucleation centers catalyzing the reduction of Au 3+ to Au 0 by the catechol groups in PDA. Accompanied by the deposition of Au , PDA films transfer from the surface of Fe 3 O 4 to that of Au as stabilizing agent. In order to confirm the reasonableness of this mechanism, two verification experiments were conducted. The presence of PDA on the surface of Fe 3 O 4@ Au – PDA nanoparticles was confirmed by the finding that glycine or ethylenediamine could be grafted onto Fe 3 O 4@ Au – PDA nanoparticles through Schiff base reaction. In addition, Fe 3 O 4@ Au – DA nanoparticles, in which DA was substituted for PDA, were prepared using the same method as that for Fe 3 O 4@ Au – PDA nanoparticles and characterized by UV-Vis, TEM and FTIR. The results validated that DA possesses multiple functions of attaching Au seeds as well as acting as both reductant and stabilizing agent, the same functions as those of PDA.

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