Exfoliating silica bilayers via intercalation at the silica/transition metal interface

Abstract The growth of the silica (SiO2) bilayer (BL) films on transition metal (TM) surfaces creates a new class of two-dimensional (2D) crystalline, self-contained materials that interact weakly with the TM substrate. The BL-silica/TM heterojunction has shown unique physical and chemical properties that can lead to new chemical reaction mechanisms under the sub-nm confinement and broad potential applications ranging from surface protection, nano transistors, molecular sieves to nuclear waste removal. Novel applications of BL-silica can be further explored as a constituent of van der Waals assembly of 2D materials. Key to these applications is an unmet technical challenge to exfoliate and transfer BL-silica films in a large area from one substrate to another without material damage. In this study, we propose a new exfoliation mechanism based on gas molecule intercalation from density functional theory studies of the BL-silica/TM heterojunction. We found that the intercalation of O atoms and CO molecules at the BL-silica/TM interface weakens the BL-silica – TM hybridization, which results in an exponential decrease of the exfoliation energy against the interface distance, as the coverage of interfacial species increases. This new intercalation mechanism opens up the opportunity for non-damaging exfoliation and transfer of large area silica bilayers.

Role of hydroxylation for the atomic structure of a non-polar vicinal zinc oxide

Communications Chemistry ◽

10.1038/s42004-020-00442-6 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Elin Grånäs ◽

Michael Busch ◽

Björn Arndt ◽

Marcus Creutzburg ◽

Guilherme Dalla Lana Semione ◽

...

Keyword(s):

Zinc Oxide ◽

Density Functional ◽

Chemical Properties ◽

Density Functional Theory Calculations ◽

Atomic Scale ◽

Water Dissociation ◽

Oxide Surface ◽

Highly Active ◽

Potential Applications ◽

AbstractFrom the catalytic, semiconducting, and optical properties of zinc oxide (ZnO) numerous potential applications emerge. For the physical and chemical properties of the surface, under-coordinated atoms often play an important role, necessitating systematic studies of their influence. Here we study the vicinal ZnO($$10\bar{1}4$$ 10 1 ¯ 4 ) surface, rich in under-coordinated sites, using a combination of several experimental techniques and density functional theory calculations. We determine the atomic-scale structure and find the surface to be a stable, long-range ordered, non-polar facet of ZnO, with a high step-density and uniform termination. Contrary to an earlier suggested nano-faceting model, a bulk termination fits much better to our experimental observations. The surface is further stabilized by dissociatively adsorbed H2O on adjacent under-coordinated O- and Zn-atoms. The stabilized surface remains highly active for water dissociation through the remaining under-coordinated Zn-sites. Such a vicinal oxide surface is a prerequisite for future adsorption studies with atomically controlled local step and terrace geometry.

Evolution of the structural, energetic, and electronic properties of the 3d, 4d, and 5d transition-metal clusters (30 TMn systems for n = 2–15): a density functional theory investigation

Physical Chemistry Chemical Physics ◽

10.1039/c7cp02240a ◽

2017 ◽

Vol 19 (23) ◽

pp. 15484-15502 ◽

Cited By ~ 44

Author(s):

Anderson S. Chaves ◽

Maurício J. Piotrowski ◽

Juarez L. F. Da Silva

Keyword(s):

Density Functional Theory ◽

Transition Metal ◽

Density Functional ◽

Metal Clusters ◽

Chemical Properties ◽

Transition Metal Clusters ◽

Functional Theory ◽

Physical And Chemical ◽

Subnanometric transition-metal (TM) clusters have attracted great attention due to their unexpected physical and chemical properties, leastwise compared to their bulk counterparts.

In-plane and vertical heterostructures from 1T’/2H transition-metal dichalcogenides

Oxford Open Materials Science ◽

10.1093/oxfmat/itab016 ◽

2022 ◽

Author(s):

Yang Ma ◽

Shiyu Xu ◽

Juntian Wei ◽

Bin Zhou ◽

Yongji Gong

Keyword(s):

Transition Metal ◽

Transition Metal Dichalcogenides ◽

Chemical Properties ◽

Chemical Vapor ◽

Deposition Process ◽

Flexible Devices ◽

Potential Applications ◽

Metal Dichalcogenides ◽

Z Contrast ◽

Abstract Objectives An avalanche of research has been carried out on two-dimensional (2D) transition metal dichalcogenides (TMDs) due to their potential applications in advanced electronics and flexible devices. To take full use of the emerging 2D TMDs materials, their in-plane/vertical heterostructures have been explored, enabling effective tuning of their physical and chemical properties. However, structural differences between the various phases impede the formation of functional heterostructures. Therefore, robust synthesis strategies for heterostructures with different phases have been explored in this study. Methods A chemical vapor deposition process has been proposed in which the key parameters like reaction sources, deposition sites, etc. have been carefully adjusted, trying to achieve simultaneous synthesis of 1T’/2H in-plane and vertical heterostructures. Results Consequently, 2D in-plane RexMo1-xS2/MoS2 and vertical ReS2/MoS2 heterostructures have been produced in different regions at the same time. Atomic-resolution Z-contrast images reveal the detailed atomic structure of the 1T’/2H interfaces. The lateral interface is found to contain Mo atoms with only 5-fold coordination with S due to the phase mismatch. Conclusion This work demonstrates a route to exploit heterostructures of different phases and opens the possibility to build more complicated 2D heterostructures using CVD.

Synthesis and Conductivity Studies of Poly(Methyl Methacrylate) (PMMA) by Co-Polymerization and Blending with Polyaniline (PANi)

Polymers ◽

10.3390/polym13121939 ◽

2021 ◽

Vol 13 (12) ◽

pp. 1939

Author(s):

Helyati Abu Hassan Shaari ◽

Muhammad Mahyiddin Ramli ◽

Mohd Nazim Mohtar ◽

Norizah Abdul Rahman ◽

Azizan Ahmad

Keyword(s):

Methyl Methacrylate ◽

Mechanical Stability ◽

Chemical Properties ◽

Cost Effective ◽

Poly Methyl Methacrylate ◽

Conducting Materials ◽

Potential Applications ◽

Polymerization Condition ◽

Physical And Chemical ◽

Poly(methyl methacrylate) (PMMA) is a lightweight insulating polymer that possesses good mechanical stability. On the other hand, polyaniline (PANi) is one of the most favorable conducting materials to be used, as it is easily synthesized, cost-effective, and has good conductivity. However, most organic solvents have restricted potential applications due to poor mechanical properties and dispersibility. Compared to PANi, PMMA has more outstanding physical and chemical properties, such as good dimensional stability and better molecular interactions between the monomers. To date, many research studies have focused on incorporating PANi into PMMA. In this review, the properties and suitability of PANi as a conducting material are briefly reviewed. The major parts of this paper reviewed different approaches to incorporating PANi into PMMA, as well as evaluating the modifications to improve its conductivity. Finally, the polymerization condition to prepare PMMA/PANi copolymer to improve its conductivity is also discussed.

A systematic computational investigations of water splitting and N2 reduction reaction performances of monolayer MBenes

Physical Chemistry Chemical Physics ◽

10.1039/d0cp06405j ◽

2021 ◽

Author(s):

Yuwen Cheng ◽

Jisheng Mo ◽

Yongtao Li ◽

Yan Song ◽

Yumin Zhang

Keyword(s):

Density Functional Theory ◽

Transition Metal ◽

Water Splitting ◽

Density Functional ◽

Reduction Reaction ◽

Functional Theory ◽

Energy Conversion And Storage ◽

Metal Borides ◽

Potential Applications ◽

And Storage

Recently, transition metal borides (MBenes, analogous to MXenes) have been attracted interest due to their potential applications in energy conversion and storage. In this work, we performed density functional theory...

Adsorption–Desorption Characteristics of ss-DNA on 2D TpTta-COF Studied by Fluorescently Labeled Oligonucleotides

NANO ◽

10.1142/s1793292021500508 ◽

2021 ◽

pp. 2150050

Author(s):

Zhaoyu Han ◽

Sen Li ◽

Shaoxian Yin ◽

Zhi-Qin Wang ◽

Yanfei Cai ◽

...

Keyword(s):

Chemical Properties ◽

Kinetic Mechanism ◽

Optical Biosensors ◽

Desorption Kinetic ◽

Wide Range ◽

Potential Applications ◽

Fluorescently Labeled Oligonucleotides ◽

Adsorption Desorption ◽

Physical And Chemical ◽

Being the newest member of the 2D materials family, 2D-nanosheet possesses many distinctive physical and chemical properties resulting in a wide range of potential applications. Recently, it was discovered that 2D COF can adsorb single-stranded DNA (ss-DNA) efficiently as well as usefully to quench fluorophores. These properties make it possible to prepare DNA-based optical biosensors using 2D COF. While practical analytical applications are being demonstrated, the fundamental understanding of binding between 2D COF and DNA in solution received relatively less attention. In this work, we carried out a systematic study to understand the adsorption and desorption kinetic, mechanism, and influencing factors of ss-DNA on the surface of 2D COF. We demonstrated that shorter DNAs are adsorbed more rapidly and bind more tightly to the surface of 2D COF. The adsorption is favored by a higher pH. The different buffer types also can affect the adsorption. In Tris-HCl solution, the adsorption reached highest efficiency. By adding the complementary DNA (cDNA), desorption of the absorbed DNA on 2D COF can be achieved. Further, desorption efficiency can also be exchanged by various surfactant in solution. These findings are important for further understanding of the interactions between DNA and COFs and for the optimization of DNA and COF-based devices and sensors.

Recent Progress in the Synthesis and Characterization of Diarylethene-based MOFs

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314087762 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1223-C1223

Author(s):

Jason Benedict ◽

Ian Walton ◽

Dan Patel ◽

Jordan Cox

Keyword(s):

Chemical Properties ◽

Building Blocks ◽

Synthesis And Characterization ◽

Next Generation ◽

Design Synthesis ◽

Thermally Induced ◽

Potential Applications ◽

External Stimuli ◽

Metal-organic Frameworks (MOFs) remain an extremely active area of research given the wide variety of potential applications and the enormous diversity of structures that can be created from their constituent building blocks. While MOFs are typically employed as passive materials, next-generation materials will exhibit structural and/or electronic changes in response to applied external stimuli including light, charge, and pH. Herein we present recent results in which advanced photochromic diarylethenes are combined with MOFs through covalent and non-covalent methods to create photo-responsive permanently porous crystalline materials. This presentation will describe the design, synthesis, and characterization of next-generation photo-switchable diarylethene based ligands which are subsequently used to photo-responsive MOFs. These UBMOF crystals are, by design, isostructural with previously reported non-photoresponsive frameworks which enables a systematic comparison of their physical and chemical properties. While the photoswitching of the isolated ligand in solution is fully reversible, the cycloreversion reaction is suppressed in the UBMOF single crystalline phase. Spectroscopic evidence for thermally induced cycloreversion will be presented, as well as a detailed analysis addressing the limits of X-ray diffraction techniques applied to these systems.

AVALIAÇÃO DA ESTRUTURA ELETRÔNICA DA FASE MONOCLINICA DO ÓXIDO DE NIÓBIO COM BASE NO USO DE DIFERENTES FUNCIONAIS DE DENSIDADE

Química Nova ◽

10.21577/0100-4042.20170779 ◽

2021 ◽

Author(s):

Kamila Ody ◽

João Jesus ◽

Carlos Cava ◽

Anderson Albuquerque ◽

Ary Maia ◽

...

Keyword(s):

Density Functional ◽

Chemical Properties ◽

Density Functionals ◽

Monoclinic Structure ◽

Functional Theory ◽

Periodic Models ◽

Physical And Chemical ◽

ASSESSMENT OF THE ELECTRONIC STRUCTURE OF THE MONOCLINIC PHASE OF NIOBIUM OXIDE BASED ON THE USE OF DIFFERENT DENSITY FUNCTIONALS. Niobium oxides, Nb2O5, are considered semiconductor materials with very attractive physical and chemical properties for applications in many areas, such as catalysis, sensors, medical, aerospace, etc. Especially, the characterization of Nb2O5-based nanostructures with monoclinic structure has received much attention in recent years. However, despite the great importance of this system, some of its fundamentals properties are still not fully understood. Hence, this work aims to apply the theoretical methodologies through Density Functional Theory (DFT) calculations in periodic models based on the use of different density functionals (like B1WC, B3PW, B3LYP, PBE0, PBESOL0, SOGGAXC, and WC1LYP) to investigate the physical and chemical properties of the monoclinic structure of Nb2O5. The band structures, energy bandgap, density of state, and vibrational properties, as well as order-disorder effects on the monoclinic structure of Nb2O5 are investigated in this study. Our theoretical results show a better agreement with experimental data for the B3LYP functional and hence lead to new perspectives on the deeper physicochemical understanding of the monoclinic Nb2O5. From these computational tools, it is possible to unravel the relations between structure and properties, which may contribute to the future development of new devices and applications based on these materials.

An emerging Janus MoSeTe material for potential applications in optoelectronic devices

Journal of Materials Chemistry C ◽

10.1039/c9tc03936h ◽

2019 ◽

Vol 7 (39) ◽

pp. 12312-12320 ◽

Cited By ~ 14

Author(s):

Xiaoyong Yang ◽

Deobrat Singh ◽

Zhitong Xu ◽

Ziwei Wang ◽

Rajeev Ahuja

Keyword(s):

First Principles ◽

Transition Metal Dichalcogenides ◽

Chemical Properties ◽

Detailed Comparison ◽

First Principles Calculations ◽

Potential Applications ◽

Metal Dichalcogenides ◽

Physical And Chemical ◽

Motivated by the extraordinary physical and chemical properties of Janus transition-metal dichalcogenides (TMDs) due to the change of the crystal field originating from their asymmetry structures, the electronic and optical properties of the MoSeTe monolayer in 2H and 1T phases are systematically studied by first-principles calculations, and a detailed comparison with the parental MoSe2 and MoTe2 monolayer is made.

Synthesis and applications of carbon nanofibers: a review

Reviews in Chemical Engineering ◽

10.1515/revce-2018-0021 ◽

2020 ◽

Vol 36 (4) ◽

pp. 493-511 ◽

Cited By ~ 5

Author(s):

Juan C. Ruiz-Cornejo ◽

David Sebastián ◽

Maria J. Lázaro

Keyword(s):

Fuel Cell ◽

Carbon Nanofibers ◽

Storage Systems ◽

Chemical Properties ◽

Catalytic Decomposition ◽

Potential Applications ◽

Catalytic Supports ◽

Physical And Chemical ◽

AbstractCarbon nanofibers (CNFs) have shown great potential in multiple applications. Their versatility is derived from the possibility of tuning their physical and chemical properties. CNFs can be synthesized using two main methods: the catalytic decomposition of carbon precursors or the electrospinning and carbonization of polymers. The most appropriate method relies on the desired characteristics of the CNFs. Some of their applications include the synthesis of catalysts and catalytic supports, as electrodes for fuel cell devices, in hydrogen storage systems, and in functional nanocomposites. In this review, recent advances in the synthesis and potential applications of CNFs are examined.