| 1. |
- Gond, Ritambhara, et al.
(författare)
-
Pyrophosphate Na2CoP2O7 Polymorphs as Efficient Bifunctional Oxygen Electrocatalysts for Zinc-Air Batteries
- 2022
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 14:36, s. 40761-40770
-
Tidskriftsartikel (refereegranskat)abstract
- Developing earth-abundant low-cost bifunctional oxygen electrocatalysts is a key approach to realizing efficient energy storage and conversion. By exploring Co-based sodium battery materials, here we have unveiled nanostructured pyrophosphate Na2CoP2O7 polymorphs displaying efficient bifunctional electrocatalytic activity. While the orthorhombic polymorph (oNCPy) has superior oxygen evolution reaction (OER) activity, the triclinic polymorph (t-NCPy) delivers better oxygen reduction reaction (ORR) activity. Simply by tuning the annealing condition, these pyrophosphate polymorphs can be easily prepared at temperatures as low as 500 degrees C. The electrocatalytic activity is rooted in the Co redox center with the (100) active surface and stable structural framework as per ab initio calculations. It marks the first case of phospho-anionic systems with both polymorphs showing stable bifunctional activity with low combined overpotential (ca. similar to 0.7 V) comparable to that of reported state-of-the-art catalysts. These nanoscale cobalt pyrophosphates can be implemented in rechargeable zinc-air batteries.
|
|
| 2. |
- Panigrahi, Puspamitra, et al.
(författare)
-
Two-Dimensional Nitrogenated Holey Graphene (C2N) Monolayer Based Glucose Sensor for Diabetes Mellitus
- 2022
-
Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 573
-
Tidskriftsartikel (refereegranskat)abstract
- Real-time monitoring of sugar molecules is crucial for diagnosis, controlling, and preventing diabetes. Here, we have proposed the potential of porous C2N monolayer-based glucose sensor to detect the sugar molecules (glucose, fructose, and xylose) by employing the van der Waals interactions corrected first-principles density functional theory and non-equilibrium Green’s function methods. The binding energy turns out to be -0.93 (-1.31) eV for glucose, -0.84 (-1.23) eV for fructose, and -0.81 (-1.30) eV for xylose in gas phase (aqueous medium). The Bader charge analysis reveals that the C2N monolayer donates charge to the sugar molecules. The dimensionless electron localization function highlights that glucose, fructose, and xylose bind through physisorption. The adsorption of sugar molecules on the C2N monolayer increases the workfunction compared to 3.54 eV (pristine C2N) with about 2.00 eV, indicating a suppressed probability of electron mobility. The electronic transport properties of C2N based device reveals distinct characteristics and zero-bias transmissions. The distinctive properties of the C2N monolayer can be indexed as promising identifiers for glucose sensors to detect blood sugar.
|
|
| 3. |
- Singh, Deobrat, et al.
(författare)
-
Eldfellite NaV(SO4)2 as a versatile cathode insertion host for Li-ion and Na-ion batteries
- 2022
-
Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 11:8, s. 3975-3986
-
Tidskriftsartikel (refereegranskat)abstract
- In search of high energy density cathode materials, the eldfellite mineral-type NaVIII(SO4)2 compound has been theoretically predicted to be a promising cathode insertion host for sodium-ion batteries. Synergizing computational and experimental investigations, the current work introduces NaVIII(SO4)2 as a novel versatile cathode for Li-ion and Na-ion batteries. Prepared by a low temperature sol-gel synthesis route, the eldfellite NaV(SO4)2 cathode exhibited an initial capacity approaching ∼79% (vs. Li+/Li) and ∼69% (vs. Na+/Na) of the theoretical capacity (1e− ≅ 101 mA h g−1) involving the V3+/V2+ redox potential centered at 2.57 V and 2.28 V, respectively. The bond valence site energy (BVSE) approach and DFT-based calculations were used to gain mechanistic insight into alkali ion migration and probe the redox center during (de)insertion of Li+/Na+ ions. Post-mortem and electrochemical titration tools revealed the occurrence of a single-phase (solid-solution) redox mechanism during reversible Li+/Na+ (de)insertion into NaVIII(SO4)2. With the multivalent vanadium redox center, eldfellite NaVIII(SO4)2 forms a new cathode insertion host for Li/Na-ion batteries with potential two-electron uptake.
|
|
| 4. |
- Ghosh, Anirudha, et al.
(författare)
-
Exotic magnetic and electronic properties of layered CrI3 single crystals under high pressure
- 2022
-
Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 105:8
-
Tidskriftsartikel (refereegranskat)abstract
- Through advanced experimental techniques on CrI3 single crystals, we derive a pressure-temperature phase diagram. We find that T-c increases to similar to 66 K with pressure up to similar to 3 GPa followed by a decrease to similar to 10 K at 21.2 GPa. The experimental results are reproduced by theoretical calculations based on density functional theory where electron-electron interactions are treated by a static on-site Hubbard U on Cr 3d orbitals. The origin of the pressure-induced reduction of the ordering temperature is associated with a decrease in the calculated bond angle, from 95 degrees at ambient pressure to similar to 85 degrees at 25 GPa. Above 22 GPa, experiment and theory jointly point to the idea that the ferromagnetically ordered state is destroyed, giving rise first to a complex, unknown magnetic configuration, and at sufficiently high pressures a pure antiferromagnetic configuration. This sequence of transitions in the magnetism is accompanied by a well-detected pressure-induced semiconductor-to-metal phase transition that is revealed by both high-pressure resistivity measurements and ab initio theory.
|
|
| 5. |
- Haman, Zakaryae, et al.
(författare)
-
Janus Aluminum Oxysulfide Al2OS : A promising 2D direct semiconductor photocatalyst with strong visible light harvesting
- 2022
-
Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 589
-
Tidskriftsartikel (refereegranskat)abstract
- Hydrogen production via solar light-driven water dissociation has been regarded as an artificial and effective process to overcome the environmental problem as well as solving the current energy crisis. In this regard, numerous works have mainly been devoted to developing the appropriate photocatalyst which satisfies the conditions for water splitting and understanding the photocatalysis process. In this study, we propose for the first time the potential application of the two-dimensional Janus aluminum oxysulfide Al2OS as an efficient photocatalyst material for hydrogen-production H-2 through the first-principles calculations. Janus Al2OS monolayer has been designed from the parental binary aluminum sulfide AlS by substituting one sub-layer of sulfide atoms (S) to oxygen atoms (O). The electronic properties of the pristine AlS and the derived Janus Al2OS were computed using GGA-PBE and HSE06 functionals. According to the band structure, AlS monolayer shows a semiconductor behavior with an indirect bandgap of 2.14 eV whereas, the Janus Al2OS exhibits a direct bandgap of 1.579 eV. Motivated by the desirable bandgap of the Janus Al2OS, the absorption-coefficient of Janus Al2OS shows strong visible light harvesting compared to the parental AlS. Furthermore, the photocatalytic performance of Al2OS has been investigated. Our calculations demonstrate that the band edge position of Al2OS is suitable for the hydrogen evolution reaction (HER). More importantly, based on the reaction coordinate, it was found that the Gibbs free-energy Delta G(H*) of Al2OS is 0.97 eV which is smaller than of the two-dimensional Janus Ga2XY (X, Y = S, Se, Te with X not equal Y) reported recently. Moreover, this value decreases from 0.97 eV to 0.69 eV under 0.5 V/angstrom of an external electrical field. Our results indicate that Janus Al2OS fulfills the fundamental requirements for efficient photo-catalyst under visible light and provides new guidance for hydrogen-production via water splitting.
|
|
| 6. |
- Kaur, Anumeet, et al.
(författare)
-
Spin and valence variation in cobalt doped barium strontium titanate ceramics
- 2022
-
Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 24:33, s. 19865-19881
-
Tidskriftsartikel (refereegranskat)abstract
- In the present decade, owing to half-metallic ferromagnetism, controlled 3d transition metal-doping based defect engineering in oxide perovskites attracts considerable attention in the pursuit of spintronics. We aim to investigate the electronic structure of Co-doped barium strontium titanate (Ba0.8Sr0.2CoxTi1-xO3 where x = 0, 0.1, 0.2) solid solution. Structural, vibrational and microscopic properties indicate the cationic substitution of Co at the octahedral Ti position along with a displacive kind of tetragonal-to-cubic phase transformation. X-ray photoelectron spectroscopy evidences the reduction in the valence state from Co3+ to Co2+ and Ti K edge X-ray absorption spectroscopy endorses the higher lattice symmetry with increasing Co doping. Orbital hybridization triggered electron hopping between O 2p and Co e(g) orbitals results in a spin fluctuation from the occupation t6(2g)g(e0) for x = 0.1 to the occupation t6(g)(2ge1)L for x = 0.20 (L designates a hole in the O 2p shell) aligned state observed from density functional theory calculations. The dominating crystal field energy as compared to intra-atomic exchange (Hund) energy decides the spin-orbital degeneracy for the Co 3d orbital to induce spin fluctuations.
|
|
| 7. |
- Khossossi, Nabil, et al.
(författare)
-
Flexible 3D porous boron nitride interconnected network as a high-performance Li-and Na-ion battery electrodes
- 2022
-
Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 421
-
Tidskriftsartikel (refereegranskat)abstract
- To achieve the high-rate efficiency in a electrochemical energy storage technologies, it is vital for the battery anode to be electronically as well as ionically conductive. Such a requirement has boosted the survey of three-dimensional (3D) porous networks made up of light-weight non-metallic elements, like carbon, boron, and nitride. A wide range of 3D porous materials composed of carbon and/or boron for Li/Na-ion batteries have been recently reported, whereas analogous efforts for lightest 3D porous boron nitride are yet to be addressed. In this work, we explore the 3D porous boron nitride network namely sp3-linked zigzag BN nanoribbons (BNNRs) with a width of 1 (lz1-BN) by assembling the 2D zigzag BNNRs and its first ever application as battery anodes for Li and Na ion batteries. Upon a consistent DFT and AIMD computations, It is revealed that the 3D porous lz1-BN ma-terial is chemically and thermally stable and yields a high specific capacity of about 539.94 mAh/g with respect to the commercialized graphite (372 mAh/g for LIBs) and recently reported Janus-graphite anode (≈332 mAh/g for SIBs), fast (Li+,Na+)-ionic diffusion, low potential voltage, and slight volume-expansion. Such puzzling electrochemical characteristics, along with the light-weight and high abundance of B and N elements, strongly support the possibility of 3D porous BN as a desirable candidate for Li and Na-ion battery anodes.
|
|
| 8. |
- Khossossi, Nabil, et al.
(författare)
-
Revealing the superlative electrochemical properties of o-B2N2 monolayer in Lithium/Sodium-ion batteries
- 2022
-
Ingår i: Nano Energy. - : Elsevier. - 2211-2855 .- 2211-3282. ; 96
-
Tidskriftsartikel (refereegranskat)abstract
- Promising flexible electrochemical energy storage systems (EESSs) are currently drawing considerable attention for their tremendous prospective end-use in portable self-powered electronic devices, including roll-up displays, and "smart "garments outfitted with piezoelectric patches to harvest energy from body movement. However, the lack of suitable battery electrodes that provides a specific electrochemical performance has made further development of these technologies challenging. Two-dimensional (2D) lightweight and flexible materials with outstanding physical and chemical properties, including mechanical strengths, hydrophilic surfaces, high surface metal diffusivity, and good conductivity, have been identified as a potential prospect for battery electrodes. In this study, taking a new 2D boron nitride allotrope, namely 2D orthorhombic diboron dinitride monolayer (o-B2N2) as representatives, we systematically explored several influencing factors, including electronic, mechanical, and their electrochemical properties (e.g., binding strength, ionic mobility, equilibrium voltage, and theoretical capacity). Considering potential charge-transfer polarization, we employed a charged electrode model to simulate ionic mobility and found ionic mobility has a unique dependence on the surface atomic configuration influenced by bond length, valence electron number, electrical conductivity, excellent ionic mobility, low equilibrium voltage with excellent stability, good flexibility, and extremely superior theoretical capacity, up to 8.7 times higher than that of widely commercialized graphite (3239.74 mAh g(-1) Vs 372 mAh g(-1)) in case of Li-ion batteries and 2159.83 mAh g(-1) in case of Na-ion batteries, indicating that the new predicted 2D o-B2N2 monolayer possess the capability to be ideal flexible anode materials for Lithium and Sodium-ion battery. Our finding provides valuable insights for experimental explorations of flexible anode candidates based on 2D o-B2N2 monolayer.
|
|
| 9. |
- Khossossi, Nabil, et al.
(författare)
-
Strong Optical Excitation and High Thermoelectric Performance in 2D Holey-Phosphorene Monolayer
- 2022
-
Ingår i: Energy Technology. - : John Wiley & Sons. - 2194-4288 .- 2194-4296. ; 10:10
-
Tidskriftsartikel (refereegranskat)abstract
- Through density functional theory (DFT)-based computations, a systematic exploration of the newly predicted 2D phosphorene allotrope, namely holey-phosphorene (HP), is carried out. It is revealed that HP shows a semiconducting nature with an indirect bandgap of 0.83 eV upon Perdew-Burke-Ernzerhof (PBE) functional. Then, to survey the optical features, a (G(0)W(0))-based approach is employed to solve the Bethe-Salpeter equation to derive the intra-layer excitonic effects. It is derived via the absorption spectrum, that HP presents an excitonic binding strength of 1.47/1.96 eV along the x/y-direction with the first peak of the absorption at 0.92/0.43 eV for the x/y-direction. The thermoelectric properties are also explored in detail and reveal a very high thermal power value along with an enhanced figure of merit (ZT) of about 3.6. The 2D HP monolayer for thermoelectric performance has high thermoelectric conversion efficiency (TCE) and is estimated to be about 22%. All these outstanding findings may be attributed to the quantum confinement effect of the porous geometry of the 2D HP nanosheet, thereby confirming its relevance as a prospect for high-performance optoelectronic and thermoelectric engineering systems.
|
|
| 10. |
- Kibbou, Moussa, et al.
(författare)
-
Probing the electronic, optical and transport properties of halide double perovskites Rb2InSb(Cl,Br)6 for solar cells and thermoelectric applications
- 2022
-
Ingår i: Journal of Solid State Chemistry. - : Elsevier. - 0022-4596 .- 1095-726X. ; 312
-
Tidskriftsartikel (refereegranskat)abstract
- Halide-based double perovskites have recently been promoted as high-performing semiconductors for photovoltaic and thermoelectricity applications owing to their outstanding efficiency, non-toxicity and ecological stability. In the framework of this research, we have systematically investigated the structural, mechanical, electronic, optical, and thermoelectric properties of Rb2InSb(Cl,Br)6 double halide perovskites. Based on Born stability and tolerance factor criteria, we have found that Rb2InSb(Cl,Br)6 are mechanically and structurally stable. Furthermore, we have performed a comprehensive evaluation of the electronic, optoelectronic, and thermoelectric characteristics. From the electronic band structure results, Rb2InSbCl6 and Rb2InSbBr6 exhibit direct semiconducting band gaps of 1.41 eV and 0.53 eV, respectively. The optical parameters of Rb2InSb(Cl,Br)6 reveal that our active structures have a higher dielectric constant, with maximum absorption in the visible range reaching over 5.68 = 105 cm1 and high optical conductivity (2.19 fs1 for Rb2InSbCl6 and 2.14 fs1 for Rb2InSbCl6). Moreover, the maximum limited spectroscopic efficiency reaches an impressive value of approximately 28.0% for Rb2InSbBr6 and 33.7% for Rb2InSbCl6. The thermoelectric properties were accurately calculated using the BoltzTraP simulation package. The obtained results reveal a significant electrical conductivity, a strong Seebeck coefficient (S 2756 mu VK1 at 300 K), and an average figure of merit close to one for both structures (ZT 1). Our findings suggest the versatility of these materials and could be used for a wide range of applications, including commercial solar cells and thermoelectricity.
|
|
