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

10.26434/chemrxiv.9850997 ◽

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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A density functional theory study of the oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide

Progress in Reaction Kinetics and Mechanism ◽

10.1177/1468678319825727 ◽

2019 ◽

Vol 44 (2) ◽

pp. 122-131

Author(s):

Bangchang Qin ◽

Yang Tian ◽

Pengxiang Zhang ◽

Zuoyin Yang ◽

Guoxin Zhang ◽

...

Keyword(s):

Density Functional Theory ◽

Free Energy ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Gibbs Free Energy ◽

Density Functional ◽

Rational Design ◽

Reduction Reaction ◽

Functional Theory ◽

Associative Mechanism

Density functional theory calculations were employed to investigate the electrochemical oxygen reduction reaction on the (111) and (100) surfaces of cobalt(II) oxide. Different mechanisms were applied to evaluate the oxygen reduction reaction performance of cobalt(II) oxide structures in terms of the Gibbs free energy and density of states. A variety of intermediate structures based on associative and dissociative mechanisms were constructed and optimized. As a result, we estimated the catalytic activity by calculating the free energy of the intermediates and constructing free energy diagrams, which suggested that the oxygen reduction reaction Gibbs free energy on cobalt(II) oxide (111) and (100) surfaces based on the associative mechanism is smaller than that based on the dissociative mechanism, demonstrating that the associative mechanism should be more likely to be the oxygen reduction reaction pathway. Moreover, the theoretical oxygen reduction reaction activity on the cobalt(II) oxide (111) surface was found to be higher than that on the cobalt(II) oxide (100) surface. These results shed light on the rational design of high-performance cobalt(II) oxide oxygen reduction reaction catalysts.

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The influence of dilute aluminum and molybdenum on stacking fault and twin formation in FeNiCoCr-based high entropy alloys based on density functional theory

Scientific Reports ◽

10.1038/s41598-019-47223-3 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Peijun Yu ◽

Yu Zhuang ◽

Jyh-Pin Chou ◽

Jie Wei ◽

Yu-Chieh Lo ◽

...

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Stacking Fault ◽

High Entropy Alloys ◽

Functional Theory ◽

High Entropy ◽

Twin Formation

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A machine learning-based alloy design system to facilitate the rational design of high entropy alloys with enhanced hardness

Acta Materialia ◽

10.1016/j.actamat.2021.117431 ◽

2021 ◽

pp. 117431

Author(s):

Chen Yang ◽

Chang Ren ◽

Yuefei Jia ◽

Gang Wang ◽

Minjie Li ◽

...

Keyword(s):

Machine Learning ◽

Rational Design ◽

Alloy Design ◽

Design System ◽

High Entropy Alloys ◽

High Entropy

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High-Entropy Alloys: Formation and Properties

ASME 2018 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries ◽

10.1115/etam2018-6732 ◽

2018 ◽

Cited By ~ 1

Author(s):

Michael C. Gao ◽

Paul D. Jablonski ◽

Jeffrey A. Hawk ◽

David E. Alman

Keyword(s):

Density Functional ◽

Thermomechanical Processing ◽

Dynamics Simulation ◽

Vacuum Induction Melting ◽

Induction Melting ◽

High Entropy Alloys ◽

Face Centered Cubic ◽

Ongoing Research ◽

High Entropy ◽

Face Centered

This paper presents ongoing research at NETL aimed at gaining fundamental understanding of high-entropy alloys (HEAs) formation and their properties, and developing highperformance HEAs for high-temperature fossil energy applications. First-principles density functional theory (DFT), Monte Carlo simulation, and molecular dynamics simulation are carried out to predict enthalpy of formation, the entropy sources (i.e., configurational entropy, vibrational entropy, and electronic entropy), and elastic properties of model single-phase HEAs with the face-centered cubic, body-centered cubic and hexagonal closed-packed structures. Classical elastic theory, which considers the interactions between dislocations and elastic fields of solutes, has also been used to predict solid solution strengthening. Large-size (∼7.5 kg) HEAs ingots are produced using vacuum induction melting and electroslag remelting methods, followed by homogenization treatment resulting in greater than 99% homogeneity. Subsequent thermomechanical processing produces fully-wrought face-centered cubic microstructures. The tensile behavior for these alloys have been determined as a function of temperature, and based on these results screening creep tests have been performed at selected temperatures and stresses.

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Reactivity of boron- and nitrogen-doped carbon nanotubes functionalized by (Pt, Eu) atoms toward O2 and CO: A density functional study

International Journal of Modern Physics C ◽

10.1142/s0129183116500753 ◽

2016 ◽

Vol 27 (07) ◽

pp. 1650075 ◽

Cited By ~ 2

Author(s):

S. Abdel Aal

Keyword(s):

Catalytic Activity ◽

Charge Transfer ◽

Density Functional ◽

Co Adsorption ◽

Energy Charge ◽

Reduction Reaction ◽

Functional Study ◽

High Catalytic Activity ◽

N Doping ◽

Different Response

The adsorption behavior and electronic properties of CO and O2 molecules at the supported Pt and Eu atoms on (5,5) armchair SWCNT have been systematically investigated within density functional theory (DFT). Fundamental aspects such as adsorption energy, natural bond orbital (NBO), charge transfer, frontier orbitals and the projected density of states (PDOS) are elucidated to analyze the adsorption properties of CO and O2 molecules. The results reveal that B- and N-doping CNTs can enhance the binding strength and catalytic activity of Pt (Eu) anchored on the doped-CNT, where boron-doping is more effective. The electronic structures of supported metal are strongly influenced by the presence of gases. After adsorption of CO and O2, the changes in binding energy, charge transfer and conductance may lead to the different response in the metal-doped CNT-based sensors. It is expected that these results could provide helpful information for the design and fabrication of the CO and O2 sensing devices. The high catalytic activity of Pt supported at doped-CNT toward the interaction with CO and O2 may be attributed to the electronic resonance particularly among Pt-5d, CO-2[Formula: see text]* and O2-2[Formula: see text]* antibonding orbitals. In contrast to the supported Eu at doped-CNT, the Eu atom becomes more positively charged, which leads to weaken the CO adsorption and promote the O2 adsorption, consequently enhancing the activity for CO oxidation and alleviating the CO poisoning of the europium catalysts. A notable orbital hybridization and electrostatic interaction between these two species in adsorption process being an evidence of strong interaction. The electronic structure of O2 adsorbed on Eu-doped CNT resembles that of O[Formula: see text], therefore the transferred charge weakens the O–O bonds and facilitates the dissociation process, which is the precondition for the oxygen reduction reaction (ORR).

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A density functional study on the oxygen reduction reaction mechanism on FeN2-doped graphene

New Journal of Chemistry ◽

10.1039/c8nj00995c ◽

2018 ◽

Vol 42 (9) ◽

pp. 6873-6879 ◽

Cited By ~ 15

Author(s):

Yuewen Yang ◽

Kai Li ◽

Yanan Meng ◽

Ying Wang ◽

Zhijian Wu

Keyword(s):

Reaction Mechanism ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Density Functional ◽

Rational Design ◽

Reduction Reaction ◽

Functional Study ◽

Highly Active ◽

Doped Graphene ◽

Commercial Applications

The rational design of heteroatom doped graphene as a highly active and non-noble oxygen reduction reaction (ORR) electrocatalyst is significant for the commercial applications of fuel cells.

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Periodic Maximum Entropy Random Structure Models for High-Entropy Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.611 ◽

2017 ◽

Vol 898 ◽

pp. 611-621 ◽

Cited By ~ 4

Author(s):

Wen Qiang Feng ◽

Shu Min Zheng ◽

Yang Qi ◽

Shao Qing Wang

Keyword(s):

Experimental Data ◽

Maximum Entropy ◽

Density Functional ◽

Lattice Distortion ◽

Maximum Entropy Principle ◽

High Entropy Alloy ◽

Random Structure ◽

High Entropy Alloys ◽

High Entropy ◽

Entropy Principle

Periodic chemically homogenized high-entropy alloy structures are constructed according to maximum entropy principle. The method can efficiently generate equimolar and non-equimolar high-entropy alloy atomic structures. Nine high-entropy alloys are simulated based on the constructed models using density functional theory techniques. The calculated lattice parameters are consistent with the available experimental data. The calculated enthalpies of mixing are more negative than the values estimated by using Miedema model, due to severe lattice distortion. The lattice distortion parameters were calculated. The results showed that fcc structure tend to stable with smaller and bcc structure with larger. The bulk modulus of Al1.5CoCrNiFe high-entropy alloys was fitted and the value is consistent with the available experimental data.

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First-Principles Studies on the Component Dependences of High-Entropy Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.338.380 ◽

2011 ◽

Vol 338 ◽

pp. 380-383 ◽

Cited By ~ 8

Author(s):

Shao Qing Wang ◽

Heng Qiang Ye

Keyword(s):

First Principles ◽

Density Functional ◽

Lattice Structure ◽

First Principles Calculation ◽

High Entropy Alloys ◽

Functional Theory ◽

High Entropy ◽

Composition Variation ◽

The Density Functional Theory

An elabrate study on the structrural and mechanical properties of the five-element FeNiCrCuCo high-entropy alloys is carried out by first-principles calculation within the density-functional theory. The combination application of plane-wave pseudopotentials and alchemical pseudoatom methods is realized to imitate the random elemental lattice occupation in the alloys. The dependence of composition variation to the crystallographic and thermodynamic properties of FeNiCrCuCo alloys in simple BCC and FCC lattices are investigated. The key role of chromium in strengthening the inter-atomic cohesion and stabilizing the lattice structure of HEAs is suggested.

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