| 1. |
- Banerjee, Amitava, et al.
(författare)
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Identifying the tuning key of disproportionation redox reaction in terephthalate : A Li-based anode for sustainable organic batteries
- 2018
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855 .- 2211-3282. ; 47, s. 301-308
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Tidskriftsartikel (refereegranskat)abstract
- The ever-increasing consumption of energy storage devices has pushed the scientific community to realize strategies toward organic electrodes with superior properties. This is owed to advantages such as economic viability and eco-friendliness. In this context, the family of conjugated dicarboxylates has emerged as an interesting candidate for the application as negative electrodes in advanced Li-ion batteries due to the revealed thermal stability, rate capability, high capacity and high cyclability. This work aims to rationalize the effects of small molecular modifications on the electrochemical properties of the terephthalate anode by means of first principles calculations. The crystal structure prediction of the investigated host compounds dilithium terephthalate (Li2TP) and diethyl terephthalate (Et2Li0TP) together with their crystal modification upon battery cycling enable us to calculate the potential profile of these materials. Distinct underlying mechanisms of the redox reactions were obtained where Li2TP comes with a disproportionation reaction while Et2Li0TP displays sequential redox reactions. This effect proved to be strongly correlated to the Li coordination number evolution upon the Li insertion into the host structures. Finally, the calculations of sublimation enthalpy inferred that polymerization techniques could easily be employed in Et2Li0TP as compared to Li2TP. Similar results are observed with methyl, propyl, and vinyl capped groups. That could be a strategy to enhance the properties of this compound placing it into the gallery of the new anode materials for state of art Li-batteries.
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| 2. |
- Nair, Akhil S., et al.
(författare)
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Unraveling the single-atom electrocatalytic activity of transition metal-doped phosphorene
- 2020
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Ingår i: Nanoscale Advances. - : Royal Society of Chemistry (RSC). - 2516-0230. ; 2:6, s. 2410-2421
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Tidskriftsartikel (refereegranskat)abstract
- The development of single-atom catalysts (SACs) for chemical reactions of vital importance in the renewable energy sector has emerged as an urgent priority. In this perspective, transition metal-based SACs with monolayer phosphorous (phosphorene) as the supporting material are scrutinized for their electrocatalytic activity towards the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) from first-principle calculations. The detailed screening study has confirmed a breaking of the scaling relationship between the ORR/OER intermediates, resulting in various activity trends across the transition metal series. Groups 9 and 10 transition metal-based SACs are identified as potential catalyst candidates with the platinum single atom offering bifunctional activity for OER and HER with diminished overpotentials. Ambient condition stability analysis of SACs confirmed a different extent of interaction towards oxygen and water compared to pristine phosphorene, suggesting room for improving the stability of phosphoreneviachemical functionalization.
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| 3. |
- Singh, Deobrat, et al.
(författare)
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Carbon-phosphide monolayer with high carrier mobility and perceptible: I - V response for superior gas sensing
- 2020
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1369-9261 .- 1144-0546. ; 44:9, s. 3777-3785
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Tidskriftsartikel (refereegranskat)abstract
- Monolayered carbon phosphide (CP), with semi-metallic electrical conductivity and graphene-like Dirac cone responses, has attracted significant attention from the advanced nanoelectronics community, for use in gas sensing devices. The CP monolayer exhibits semi-metallic behavior in the x-direction and semi-conducting behavior in the y-direction. With the presence of graphene-like Dirac cones, it holds highly anisotropic carrier mobility characteristics. Here, we introduce the first-principle theoretical calculations for understanding the adsorption mechanism of different gas molecules-CO, CO2, NH3, NO and NO2-on the monolayer for electronic sensing devices. The binding strengths of these gas molecules adsorbed on the CP layer are much stronger than for other reported two-dimensional materials, such as graphene, blue phosphorene, germanene, etc. Additionally, the charge transfer analysis also supported an enhanced binding strength due to the sufficient amount of charge sharing between the CP monolayer and gas molecules. We further present an extensive study about the transport properties of CP monolayer sensor devices with electrodes made out of identical materials. The transmission characteristics, the density of states, and I-V response are supported by analysis of the charge distribution of the CP monolayer upon adsorption of CO, CO2, NH3, NO and NO2. Molecules have been calculated using density functional theory and non-equilibrium Green's function. The presented theoretical investigations reveal that the CP monolayer-based device exhibits improved characteristics and could be the foundation towards constructing highly sensitive nanosensor devices.
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| 4. |
- Singh, Deobrat, et al.
(författare)
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Van der Waals induced molecular recognition of canonical DNA nucleobases on a 2D GaS monolayer
- 2020
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : ROYAL SOC CHEMISTRY. - 1463-9076 .- 1463-9084. ; 22:12, s. 6706-6715
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we systematically investigated the adsorption mechanism of canonical DNA nucleobases and their two nucleobase pairs on a single-layer gallium sulfide (GaS) substrate using DFT+D3 methods. The GaS substrate has chemical interactions with molecules 0.02 |e| 0.11 |e| from molecules to the monolayer GaS surface. Due to the chemical interactions of adenine, cytosine, guanine, and thymine on the monolayer GaS surface, the work function is decreased by 0.69, 0.60, 0.97, and 0.20 eV, respectively. It is displayed that the bandgap of the monolayer GaS sheet can be significantly affected as induced molecular electronic states tend to appear near the Fermi level region due to chemical and physisorption mechanism. We have also investigated the transport properties of DNA nucleobases, namely, AT and GC pair molecules on the GaS surface, which shows significant reduction in the zero-bias transmission spectra. Moreover, with and without DNA nucleobases, namely, AT and GC pair molecules' absorptions on the GaS surface, clearly expressed in terms of distinct current signals, can be observed as ON and OFF states for this device. The distinctive nucleobase adsorption energies and different I-V responses may serve as potential probes for the selective detection of nucleobase molecules in imminent DNA sequencing applications based on a monolayer GaS surface.
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| 5. |
- Zhao, Xiaofeng, et al.
(författare)
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Strain-Engineered Metal-Free h-B2O Monolayer as a Mechanocatalyst for Photocatalysis and Improved Hydrogen Evolution Reaction
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 124:14, s. 7884-7892
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Tidskriftsartikel (refereegranskat)abstract
- Developing stable metal-free materials with a highly efficient hydrogen evolution reaction (HER) has received intense research interest due to its renewable and environmentally friendly properties. In this work, we systematically investigated the HER catalytic activity of a new h-B2O monolayer based on first-principles calculations. The results show the B site in the h-B2O structure is energetically favorable for hydrogen with the calculated Gibbs free energy (Delta G(H*)) of -0.07 eV, which is comparable to that of the Pt catalyst (Delta G(H*)) = -0.09 eV). Moreover, the catalytic activity of the h-B2O monolayer is quite robust with increasing hydrogen coverages (from 1/9 to 9/9). Interestingly, the HER activity of the h-B2O monolayer is sensitive to the strains-driven. For example, applied tensile strains (0-2%) could weaken the bonding between hydrogen and the substrate, resulting in Delta G(H*) even close to 0 eV. However, the opposite trend is found for applied compressive strain. After analyzing the density of states (DOS), we found the h-B2O monolayer with absorbed hydrogen retains the metallic property, still exhibiting excellent electrical conductivity. These results reveal that the metal-free h-B2O monolayer is a promising candidate for HER applications.
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| 6. |
- Singh, Deobrat, et al.
(författare)
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Harnessing the unique properties of MXenes for advanced rechargeable batteries
- 2021
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Ingår i: JPhys Energy. - : IOP Publishing. - 2515-7655. ; 3:1
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Forskningsöversikt (refereegranskat)abstract
- In recent years, two-dimensional MXenes have been emerged as potential electrode materials for rechargeable batteries due to their unique properties such as exceptional safety, significant interlayer spacing, environmental flexibility, large surface area, high electrical conductivity, and excellent thermal stability. This review examined all of the recent advances in the field of MXenes and their composites (hybrid structures), which are found to be useful for the electrochemical applications of advanced rechargeable batteries. The main focus of this review is on metal-ion batteries and lithium-sulfur (Li-S) batteries. It is intended to show that the combination of recent improvements in the synthesis and characterization, greater control of the interlayer distance, and new MXene composites, together serve as an emerging and potential way for energy storage applications.
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| 7. |
- Anikina, Ekaterina, et al.
(författare)
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Tunning Hydrogen Storage Properties of Carbon Ene-Yne Nanosheets through Selected Foreign Metal Functionalization
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:31, s. 16827-16837
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have employed density functional theory with a range of van der Waals corrections to study geometries, electronic structures, and hydrogen (H-2) storage properties of carbon ene-yne (CEY) decorated with selected alkali (Na, K) and alkaline-earth metals (Mg, Ca). We found that all metals, except Mg, bind strongly by donating a major portion of their valence electrons to the CEY monolayers. Thermal stabilities of representative systems, Ca-decorated CEY monolayers, have been confirmed through ab initio molecular dynamics simulations (AIMD). We showed that each metal cation adsorbs multiple H-2 with binding energies (E-bind) considerably stronger than on pristine CEY. Among various metal dopants, Ca stands out with the adsorption of five H-2 per each Ca having E-bind values within the desirable range for effective adsorption/desorption process. The resulting gravimetric density for CEY@Ca has been found around 6.0 wt % (DFT-D3) and 8.0 wt % (LDA), surpassing the U.S. Department of Energy's 2025 goal of 5.5 wt %. The estimated H-2 desorption temperature in CEY@Ca exceeds substantially the boiling point of liquid nitrogen, which confirms its potential as a practical H-2 storage medium. We have also employed thermodynamic analysis to explore the H-2 adsorption/desorption mechanism at varied conditions of temperature and pressure for real-world applications.
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| 8. |
- Boota, M., et al.
(författare)
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Mechanistic Understanding of the Interactions and Pseudocapacitance of Multi-Electron Redox Organic Molecules Sandwiched between MXene Layers
- 2021
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 7:4, s. 2001202-
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Tidskriftsartikel (refereegranskat)abstract
- Using a combined theoretical and experimental approach, a mechanistic understanding of the interactions and pseudocapacitance of different quinone-coupled viologen and pyridiniumium molecules sandwiched between titanium carbide (Ti3C2Tx) MXene layers has been provided. Three different derivatives of quinone-coupled viologen and pyridiniumium are synthesized using nucleophilic substitution reaction and subsequently hybridized with Ti3C2Tx MXene (organic@Ti3C2Tx) using self-assembly approach. The atomic structure of pristine Ti3C2Tx and organic@Ti3C2Tx hybrid films is investigated using grazing incidence X-ray diffraction and X-ray pair distribution function analysis using synchrotron radiation. Spectroscopic results confirm the coupling of quinones with viologen and pyridiniumium molecules and their non-covalent functionalization to the MXene without their catalytic decomposition. First-principles calculations confirm that the preferred orientation of organic molecules upon intercalation/adsorption is horizontal to the Ti3C2Tx surface. The authors reveal that these molecules attach to the Ti3C2Tx surface with a significantly high binding energy (up to −2.77 eV) via a charge transfer mechanism. The electronic structure calculations show that all organic@Ti3C2Tx hybrids preserved their metallic behavior. Free-standing organic@Ti3C2Tx hybrid films show a more than three times higher capacitance at ultra-high scan rates (up to 20 V s−1) compared to their pristine counterpart due to molecular pillaring of organic molecules between Ti3C2Tx layers via strong binding energies and charge transfer.
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| 9. |
- Bouziani, Ilyas, et al.
(författare)
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Computational prediction of two-dimensional o-Al2N2 under applied strain for boosting the photocatalytic hydrogen evolution reaction performance
- 2023
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 48:91, s. 35542-35551
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Tidskriftsartikel (refereegranskat)abstract
- Photocatalytic water splitting for clean hydrogen fuel production provides a promising approach to solve the energy and environmental issues. Recently, two-dimensional (2D) photocatalysts have attracted growing interest owing to their short carrier diffusion path, abundant active sites and large surface area. This study explores the photocatalytic performance of 2D orthorhombic dialuminum dinitride (o-Al2N2) using density functional theory. The computational results show that the o-Al2N2 monolayer has a semiconductor character with indirect and moderate bandgap. Moreover, this system exhibits high light absorption in the visible region, referring to its high capacity for harvesting sunlight. Meanwhile, under neutral pH, the band edge positions are suitable to straddle water redox potentials and the hydrogen evolution reaction is energetically favorable to allow hydrogen production on the surface of 2D o-Al2N2 compound. More importantly, the photocatalytic activity of o-Al2N2 monolayer is significantly improved under slight biaxial compressive strain. Therefore, our findings suggest that the o-Al2N2 nanomaterial is a highly efficient 2D photocatalyst for hydrogen production via water splitting under neutral pH.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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| 10. |
- Bouziani, Ilyas, et al.
(författare)
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Janus Ga2SeTe and In2SeTe nanosheets : Excellent photocatalysts for hydrogen production under neutral pH
- 2023
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 48:43, s. 16358-16369
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Tidskriftsartikel (refereegranskat)abstract
- In the past few years, Janus nanosheets have attracted much interest according to their specific structure and considerable potential to address the energy and environmental issues. Herein, the electronic, optical and photocatalytic properties of two-dimensional Janus Ga2SeTe and In2SeTe have been studied using ab-initio computations based on the density functional theory. The obtained results show that these nanomaterials exhibit a semiconductor behavior with direct and moderate bandgaps using hybrid HSE06 func-tional. Subsequently, the understudied compounds present suitable optical conductivity, absorption, transmission and reflectivity for water splitting under the ultraviolet-visible light irradiation. Interestingly, the band edge positions of Janus Ga2SeTe and In2SeTe excellently straddle the redox potentials of water under neutral pH. Additionally, the free energy values for the formation of H2 from H adsorbed on the Ga2SeTe and In2SeTe com-pounds are respectively 1.304eV and 0.976eV at pH = 7. More excitingly, the present study proposes strain engineering approach to improve the photocatalytic performance of the Janus Ga2SeTe and In2SeTe monolayers. Specifically, the investigated semiconductors show more appropriate band edge alignment and better hydrogen evolution reaction ac-tivity under biaxial tensile strain, which fulfil the water splitting requirements at neutral pH conditions. Our findings conclude that the Janus Ga2SeTe and In2SeTe nanosheets are promising candidates for photocatalytic hydrogen production.
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