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

ACS Catalysis ◽  
2020 ◽  
Vol 10 (18) ◽  
pp. 10390-10398
Author(s):  
Rituja B. Patil ◽  
Stephen D. House ◽  
Aayush Mantri ◽  
Judith C. Yang ◽  
James R. McKone
Keyword(s):  
Direct Observation ◽  
Bimetallic Catalyst ◽  
Thermal Reduction ◽  
Nickel Molybdate ◽  
Catalyst Formation

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.

Direct Observation of Single Atoms in Sinter-Resistant and Bimetallic Catalyst Systems Synthesized by Atomic Layer Deposition

2013 ◽  
Vol 19 (S2) ◽  
pp. 1706-1707
Author(s):  
K.-B. Low ◽  
Y. Lei ◽  
J. Lu ◽  
J.W. Elam
Keyword(s):  
Atomic Layer Deposition ◽  
Direct Observation ◽  
Bimetallic Catalyst ◽  
Atomic Layer ◽  
Single Atoms ◽  
Layer Deposition ◽  
Catalyst Systems

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Application of a Simple Cold Stub to the Direct Observation of Frozen Hydrated Sand

1973 ◽  
Vol 31 ◽  
pp. 212-213
Author(s):  
John M. Wehrung ◽  
Richard J. Harniman
Keyword(s):  
United States ◽  
Surface Water ◽  
Direct Observation ◽  
Controlled Study ◽  
Clay Particles ◽  
Organic Debris ◽  
Rock Formations ◽  
Water Tables ◽  
Permeable Rock ◽  
Natural Means

Water tables in aquifer regions of the southwest United States are dropping off at a rate which is greater than can be replaced by natural means. It is estimated that by 1985 wells will run dry in this region unless adequate artificial recharging can be accomplished. Recharging with surface water is limited by the plugging of permeable rock formations underground by clay particles and organic debris.A controlled study was initiated in which sand grains were used as the rock formation and water with known clay concentrations as the recharge media. The plugging mechanism was investigated by direct observation in the SEM of frozen hydrated sand samples from selected depths.

Direct Observation of the Diffusionless β → β + ω Transformation in Titanium Alloys

1971 ◽  
Vol 29 ◽  
pp. 122-123
Author(s):  
N. E. Paton ◽  
D. de Fontaine ◽  
J. C. Williams
Keyword(s):  
Electron Microscope ◽  
Titanium Alloys ◽  
Direct Observation ◽  
Dark Field ◽  
X Ray Diffraction ◽  
Resistivity Measurements ◽  
Selected Area Electron Diffraction ◽  
Ti Alloys ◽  
Thin Foils ◽  
Field Device

The electron microscope has been used to study the diffusionless β → β + ω transformation occurring in certain titanium alloys at low temperatures. Evidence for such a transformation was obtained by Cometto et al by means of x-ray diffraction and resistivity measurements on a Ti-Nb alloy. The present work shows that this type of transformation can occur in several Ti alloys of suitable composition, and some of the details of the transformation are elucidated by means of direct observation in the electron microscope.Thin foils were examined in a Philips EM-300 electron microscope equipped with a uniaxial tilt, liquid nitrogen cooled, cold stage and a high resolution dark field device. Selected area electron diffraction was used to identify the phases present and the ω-phase was imaged in dark field by using a (101)ω reflection. Alloys were water quenched from 950°C, thinned, and mounted between copper grids to minimize temperature gradients in the foil.

A New 1000kv Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 100-101
Author(s):  
J.L. Williams ◽  
K. Heathcote ◽  
E.J. Greer
Keyword(s):  
Electron Microscope ◽  
Direct Observation ◽  
High Voltage ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Specimen Thickness ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
Dynamic Experiments ◽  
Conventional Instrument

High Voltage Electron Microscope already offers exciting experimental possibilities to Biologists and Materials Scientists because the increased specimen thickness allows direct observation of three dimensional structure and dynamic experiments on effectively bulk specimens. This microscope is designed to give maximum accessibility and space in the specimen region for the special stages which are required. At the same time it provides an ease of operation similar to a conventional instrument.

Structure and composition of metal particles in Pt-Sn/Al2O3 bimetallic catalysts

1990 ◽  
Vol 48 (4) ◽  
pp. 278-279
Author(s):  
A. Sachdev ◽  
J. Schwank
Keyword(s):  
Bimetallic Catalysts ◽  
Bimetallic Catalyst ◽  
Size Structure ◽  
High Surface ◽  
High Surface Area ◽  
Metal Particles ◽  
Alloy Formation ◽  
Particle Size Range ◽  
Oxide Supports ◽  
Petroleum Fractions

Platinum - tin bimetallic catalysts have been primarily utilized in the chemical industry in the catalytic reforming of petroleum fractions. In this process the naphtha feedstock is converted to hydrocarbons with higher octane numbers and high anti-knock qualities. Most of these catalysts contain small metal particles or crystallites supported on high surface area insulating oxide supports. The determination of the structure and composition of these particles is crucial to the understanding of the catalytic behavior. In a bimetallic catalyst it is important to know how the two metals are distributed within the particle size range and in what way the addition of a second metal affects the size, structure and composition of the metal particles. An added complication in the Pt-Sn system is the possibility of alloy formation between the two elements for all atomic ratios.

Direct Observation of Monolayer Zones in Al-wt 4% Cu

1990 ◽  
Vol 48 (1) ◽  
pp. 14-15
Author(s):  
B. Jouffrey ◽  
D. Dorignac ◽  
A. Bourret
Keyword(s):  
Solid Solution ◽  
Synchrotron Radiation ◽  
Direct Observation ◽  
Supersaturated Solid Solution ◽  
Original Model ◽  
X Ray ◽  
Image Position

Since the early works on GP zones and the model independently proposed by Preston and Guinier on the first steps of precipitation in supersaturated solid solution of aluminium containing a few percent of copper, many works have been performed to understand the structure of different stages in the sequence of precipitation.The scheme which is generally admitted can be drawn from a work by Phillips.In their original model Guinier and Preston analysed a GP zone as composed of a single (100) copperrich plane surrounded by aluminum atomic planes with a slightly shorter distance from the original plane than in the solid solution.From X-ray measurements it has also been shown that GP1 zones were not only copper monolayer zones. They could be up to a few atomic planes thick. Different models were proposed by Guinier, Gerold, Toman. Using synchrotron radiation, proposals have been recently made.

Sign in / Sign up

Export Citation Format

Share Document