Tunable intrinsic strain in two-dimensional transition metal electrocatalysts

Science ◽  
2019 ◽  
Vol 363 (6429) ◽  
pp. 870-874 ◽  
Author(s):  
Lei Wang ◽  
Zhenhua Zeng ◽  
Wenpei Gao ◽  
Tristan Maxson ◽  
David Raciti ◽  
...  
Keyword(s):  
Transition Metal ◽  
Density Functional ◽  
Compressive Strain ◽  
Density Functional Theory Calculations ◽  
Surface Strain ◽  
Fine Tuning ◽  
Two Dimensional ◽  
Level Control ◽  
Surface Stresses ◽  
Intrinsic Strain

Tuning surface strain is a powerful strategy for tailoring the reactivity of metal catalysts. Traditionally, surface strain is imposed by external stress from a heterogeneous substrate, but the effect is often obscured by interfacial reconstructions and nanocatalyst geometries. Here, we report on a strategy to resolve these problems by exploiting intrinsic surface stresses in two-dimensional transition metal nanosheets. Density functional theory calculations indicate that attractive interactions between surface atoms lead to tensile surface stresses that exert a pressure on the order of 105atmospheres on the surface atoms and impart up to 10% compressive strain, with the exact magnitude inversely proportional to the nanosheet thickness. Atomic-level control of thickness thus enables generation and fine-tuning of intrinsic strain to optimize catalytic reactivity, which was confirmed experimentally on Pd(110) nanosheets for the oxygen reduction and hydrogen evolution reactions, with activity enhancements that were more than an order of magnitude greater than those of their nanoparticle counterparts.

scholarly journals Water dissociation and association on mirror twin boundaries in two-dimensional MoSe2: insights from density functional theory calculations

2021 ◽  
Author(s):  
Thomas Joseph ◽  
Mahdi Ghorbani-Asl ◽  
Matthias Batzill ◽  
Arkady V Krasheninnikov
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Point Defects ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Water Dissociation ◽  
Water Molecules ◽  
Two Dimensional ◽  
Functional Theory ◽  
Adsorption And Dissociation

The adsorption and dissociation of water molecules on two-dimensional transition metal dichalco- genides (TMDs) is expected to be dominated by point defects, such as vacancies, and edges. At the same...

scholarly journals Prediction of nodal-line semimetals in two-dimensional black phosphorous films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiaojuan Liu ◽  
Hairui Bao ◽  
Yue Li ◽  
Zhongqin Yang
Keyword(s):  
Fermi Level ◽  
Mirror Symmetry ◽  
Density Functional ◽  
Compressive Strain ◽  
Density Functional Theory Calculations ◽  
Nodal Line ◽  
Two Dimensional ◽  
Functional Theory ◽  
Two Dimensional Materials ◽  
Valence Bands

AbstractSemimetals are a new kind of quantum materials, in which the conduction and valence bands cross each other near the Fermi level. Based on density-functional theory calculations and symmetry analysis, we propose nodal-line semimetals in layered stacked black phosphorus (BP) films which are designed to have a mirror symmetry lying in the BP layer plane and thus rendering them different from the BP film systems previously studied. A closed nodal-line degenerate band can appear around the Fermi level in the BP films after a biaxial compressive strain is applied. The calculated Z2 number of Z2 =  − 1 indicates the robustness of the nodal-line semimetals obtained in the BP films, protected by the in-plane mirror symmetry. Intriguingly, with the increase of the film thickness, a smaller biaxial compressive strain is required to produce the nodal-line semimetals, more accessible in experiments. Our results provide a promising route to carrying out the nodal-line semimetals based on various two-dimensional materials.

scholarly journals Detection of adsorbed transition-metal porphyrins by spin-dependent conductance of graphene nanoribbon

RSC Advances ◽  
2017 ◽  
Vol 7 (46) ◽  
pp. 29112-29121 ◽  
Author(s):  
Peter Kratzer ◽  
Sherif Abdulkader Tawfik ◽  
Xiang Yuan Cui ◽  
Catherine Stampfl
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Electronic Transport ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Graphene Nanoribbon ◽  
Functional Theory ◽  
Metal Porphyrins

Electronic transport in a zig-zag-edge graphene nanoribbon (GNR) and its modification by adsorbed transition metal porphyrins is studied by means of density functional theory calculations.

Exploring the possibilities of two-dimensional transition metal carbides as anode materials for sodium batteries

2015 ◽  
Vol 17 (7) ◽  
pp. 5000-5005 ◽  
Author(s):  
Eunjeong Yang ◽  
Hyunjun Ji ◽  
Jaehoon Kim ◽  
Heejin Kim ◽  
Yousung Jung
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Electrochemical Properties ◽  
Anode Materials ◽  
Density Functional ◽  
Two Dimensional ◽  
Metal Carbides ◽  
Functional Theory ◽  
Transition Metal Carbides ◽  
Sodium Batteries

MXenes are predicted to be a family of promising Na anode materials with desirable electrochemical properties using density functional theory.

scholarly journals Nanoribbons with Non-Alternant Topology from Fusion of Polyazulene: Carbon Allotropes Beyond Graphene

2019 ◽  
Author(s):  
Qitang Fan ◽  
Daniel Martin-Jimenez ◽  
Daniel Ebeling ◽  
Claudio K. Krug ◽  
Lea Brechmann ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Low Temperature ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Scanning Probe ◽  
Two Dimensional ◽  
Reaction Step ◽  
Functional Theory ◽  
Carbon Allotropes ◽  
Temperature Scanning

Various two-dimensional (2D) carbon allotropes with non-alternant topologies, such as pentaheptites and phagraphene, have been proposed. Predictions indicate that these metastable carbon polymorphs, which contain odd-numbered rings, possess unusual (opto)electronic properties. However, none of these materials has been achieved experimentally due to synthetic challenges. In this work, by using on-surface synthesis, nanoribbons of the non-alternant graphene allotropes, phagraphene and tetra-penta-hepta(TPH)-graphene have been obtained by dehydrogenative C-C coupling of 2,6-polyazulene chains. These chains were formed in a preceding reaction step via on-surface Ullmann coupling of 2,6-dibromoazulene. Low-temperature scanning probe microscopies with CO-functionalized tip and density functional theory calculations have been used to elucidate their structural properties. <br>

scholarly journals Selective 13C labelling reveals the electronic structure of flavocoenzyme radicals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Erik Schleicher ◽  
Stephan Rein ◽  
Boris Illarionov ◽  
Ariane Lehmann ◽  
Tarek Al Said ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Blue Light ◽  
Density Functional ◽  
Double Resonance ◽  
Density Functional Theory Calculations ◽  
Microwave Frequency ◽  
Fine Tuning ◽  
Electron Nuclear Double Resonance ◽  
Intermediate Radical ◽  
Wide Range

AbstractFlavocoenzymes are nearly ubiquitous cofactors that are involved in the catalysis and regulation of a wide range of biological processes including some light-induced ones, such as the photolyase-mediated DNA repair, magnetoreception of migratory birds, and the blue-light driven phototropism in plants. One of the factors that enable versatile flavin-coenzyme biochemistry and biophysics is the fine-tuning of the cofactor’s frontier orbital by interactions with the protein environment. Probing the singly-occupied molecular orbital (SOMO) of the intermediate radical state of flavins is therefore a prerequisite for a thorough understanding of the diverse functions of the flavoprotein family. This may be ultimately achieved by unravelling the hyperfine structure of a flavin by electron paramagnetic resonance. In this contribution we present a rigorous approach to obtaining a hyperfine map of the flavin’s chromophoric 7,8-dimethyl isoalloxazine unit at an as yet unprecedented level of resolution and accuracy. We combine powerful high-microwave-frequency/high-magnetic-field electron–nuclear double resonance (ENDOR) with 13C isotopologue editing as well as spectral simulations and density functional theory calculations to measure and analyse 13C hyperfine couplings of the flavin cofactor in DNA photolyase. Our data will provide the basis for electronic structure considerations for a number of flavin radical intermediates occurring in blue-light photoreceptor proteins.

scholarly journals Mechanochemical Synthesis of a Mercury(II) Metal-Organic Framework Reveals a Two-Dimensional Polymorph Stabilized by Weak Interactions

2019 ◽  
Author(s):  
Isaiah R. Speight ◽  
Igor Huskić ◽  
Mihails Arhangelskis ◽  
Hatem M. Titi ◽  
Robin Stein ◽  
...  
Keyword(s):  
Density Functional ◽  
Weak Interactions ◽  
Metal Organic Framework ◽  
Three Dimensional ◽  
Density Functional Theory Calculations ◽  
Dimensional Structure ◽  
Reaction Monitoring ◽  
Two Dimensional ◽  
Functional Theory ◽  
Metal Organic

Solid-state mechanochemistry revealed a novel polymorph of the mercury(II) imidazolate framework, based on square-grid (sql) topology layers. Reaction monitoring and periodic density functional theory calculations show that the sql-structure is of higher stability than the previously reported three-dimensional structure, with the unexpected stabilization of a lower dimensionality structure explained by contributions of weak interactions, which include short C-H···Hg contacts.

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