Processing and properties of high entropy carbides

Layered LixMO2 materials, a new class of high-entropy oxides, have been synthesized by nebulized spray pyrolysis. Specifically, the lattice structure of Li(Ni1/3Mn1/3Co1/3)O2 (NCM111) cathode material has been replicated successfully while increasing the number of cations in equimolar proportions, thereby allowing transition to high-entropy oxide materials.

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High-Entropy Alloys as Catalysts for the CO2 and CO Reduction Reactions

10.26434/chemrxiv.9850997.v1 ◽

2019 ◽

Author(s):

Jack Pedersen ◽

Thomas Batchelor ◽

Alexander Bagger ◽

Jan Rossmeisl

Keyword(s):

Density Functional ◽

Rational Design ◽

Hydrogen Adsorption ◽

Co Adsorption ◽

Reduction Reaction ◽

Supervised Machine Learning ◽

High Entropy Alloys ◽

High Entropy ◽

Co Reduction ◽

Disordered Alloy

Using the high-entropy alloys (HEAs) CoCuGaNiZn and AgAuCuPdPt as starting points we provide a framework for tuning the composition of disordered multi-metallic alloys to control the selectivity and activity of the reduction of carbon dioxide (CO2) to highly reduced compounds. By combining density functional theory (DFT) with supervised machine learning we predicted the CO and hydrogen (H) adsorption energies of all surface sites on the (111) surface of the two HEAs. This allowed an optimization for the HEA compositions with increased likelihood for sites with weak hydrogen adsorption{to suppress the formation of molecular hydrogen (H2) and with strong CO adsorption to favor the reduction of CO. This led to the discovery of several disordered alloy catalyst candidates for which selectivity towards highly reduced carbon compounds is expected, as well as insights into the rational design of disordered alloy catalysts for the CO2 and CO reduction reaction.

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Instant and Persistent Hydrogen Production Using Nano High Entropy Catalyst

10.26434/chemrxiv.9777257.v1 ◽

2019 ◽

Author(s):

Nirmal Kumar ◽

Subramanian Nellaiappan ◽

Ritesh Kumar ◽

Kirtiman Deo Malviya ◽

K. G. Pradeep ◽

...

Keyword(s):

Formic Acid ◽

Minimum Energy ◽

High Entropy Alloy ◽

Hydrogen Energy ◽

High Entropy ◽

Electro Oxidation ◽

The Individual ◽

Novel Catalyst ◽

Cell Anode ◽

Fuel Cell Anode

<div>Renewable harvesting clean and hydrogen energy using the benefits of novel multicatalytic materials of high entropy alloy (HEA equimolar Cu-Ag-Au-Pt-Pd) from formic acid with minimum energy input has been achieved in the present investigation. The synthesis effect of pristine elements in the HEA drives the electro-oxidation reaction towards non-carbonaceous pathway . The atomistic simulation based on DFT rationalize the distinct lowering of the d-band center for the individual atoms in the HEA as compared to the pristine counterparts. This catalytic activity of the HEA has also been extended to methanol electro-oxidation to show the unique capability of the novel catalyst. The nanostructured HEA, properties using a combination of casting and cry omilling techniques can further be utilized as fuel cell anode in direct formic acid/methanol fuel cells (DFFE). </div>

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