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Klaa, K., Labidi, S., Banerjee, A., Chakraborty, S., Labidi, M., Amara, A., . . . Ahuja, R. (2019). Composition dependent tuning of electronic and magnetic properties in transition metal substituted Rock-salt MgO. Journal of Magnetism and Magnetic Materials, 475, 44-53
Open this publication in new window or tab >>Composition dependent tuning of electronic and magnetic properties in transition metal substituted Rock-salt MgO
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2019 (English)In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 475, p. 44-53Article in journal (Refereed) Published
Abstract [en]

Full potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT) is used to investigate the structural, electronic and magnetic properties of Fe and Ni (3d transition metal) substituted Rock-salt wide band gap insulator Mg1-xMxO (M = Fe, Ni). We have performed spin polarized calculations throughout this work with generalized gradient approximation (GGA) type exchange correlation functional. Additionally, the electronic structures and density of states are computed using modified Becke-Johnson (mBJ) potential based approximation with the inclusion of coulomb energy (U = 7 eV). Based on the Vegard's law and structural optimization, the lattice parameter and bulk modulus are found to be in good agreement with experimental values. Moreover, the analysis of electronic band structures reveals an insulating character for Ni substituted MgO while semiconducting and half-metallic character for Fe substituted case. It has been found that the p-d super-exchange interaction provides a ferromagnetic character due to the 3d transition metal impurities and oxygen atom. The observed p-d hybridization at the top of the valence band edge in this investigations could be useful for magneto-optic and spintronic applications.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2019
Keywords
FP-LAPW, mBJ plus U, P-d exchange interaction, Half-metallic, Magnetic moment
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-378617 (URN)10.1016/j.jmmm.2018.11.065 (DOI)000458152000008 ()
Funder
Swedish Research CouncilCarl Tryggers foundation
Available from: 2019-03-11 Created: 2019-03-11 Last updated: 2019-03-11Bibliographically approved
Banerjee, A. (2019). Materials Modelling for Energy Harvesting: From Conversion to Application through Storage. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Materials Modelling for Energy Harvesting: From Conversion to Application through Storage
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this Ph.D. thesis, ab initio density functional theory along with molecular dynamics and global optimization methods are used to unveil and understand the structures and properties of energy relevant materials. In this connection, the following applications are considered: i. electrocatalyst for solar fuel production through water splitting, ii. hybrid perovskite solar cell for generation of electrical energy and iii. Battery materials to store the electrical energy. The water splitting mechanism in terms of hydrogen evolution and oxygen evolution reactions (HER and OER) on the catalytic surfaces has been envisaged based on the free energy diagram, named reaction coordinate, of the reaction intermediates. The Ti-functionalized two-dimensional (2D) borophene monolayer has been emerged as a promising material for HER and OER mechanisms as compared to the pristine borophene sheet. Further investigation in the series of this noble metal free monolayer catalyst is 2D Al2C monolayer both in form of pristine and functionalized with nitrogen (N), phosphorous (P), boron (B), and sulphur (S). It has been observed that only B substituted Al2C shows very close to thermoneutral, that could be the most promising candidate for HER on functionalized Al2C monolayer. The adsorption of O* intermediate is stronger in S-substituted Al2C, whereas it is less strongly adsorbed on N-substituted Al2C. The subsequent consideration is being the case of n-type doping (W) along with Ti codoped in BiVO4 to enhance the efficiency of BiVO4 photoanode for water splitting. The determined adsorption energy and corresponding Gibbs free energies depict that the Ti site is energetically more favorable for water splitting. Moreover, the Ti site possesses a lower overpotential in the W–Ti codoped sample as compared to the mono-W doped sample. We have also explored the effect of mixed cation and mixed anion substitution in the hybrid perovskite in terms of structural stability, electronic properties and optical response of hybrid perovskite crystal structures. It has been found that the insertion of bromine (Br) into the system could modulate the stability of the Guanidinium lead iodide (GAPbI3) hybrid perovskite.  Moreover, the band gap of the mixed hybrid perovskite is increased with the inclusion of smaller Br anion while replacing partially the larger iodine (I) anion. Finally the electrochemical storage mechanism for Sodium (Na) and lithium (Li) ion insertion has been envisaged in inorganic electrode (eldfellite, NaFe(SO4)2) as well as in more sustainable organic electrode (di-lithium terephthalate, Li2TP). The full desodiation capability of the eldfellite enhances the capacity while the activation energies (higher than 1 eV) for the Na+ ion diffusion for the charged state lower the ionic insertion rate. The key factor as the variation of Li-O coordination in the terephthalate, for the disproportionation redox reaction in Li2TP is also identified.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2019. p. 96
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1760
Keywords
Materials Modelling, DFT, Energy Materials, Photocatalysis, HER and OER, Hybrid Perovskite Solar Cells, Stability, Thermodynamics and Kinetics in Na-ion battery, Organic Crystal Battery
National Category
Condensed Matter Physics Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-369695 (URN)978-91-513-0544-8 (ISBN)
Public defence
2019-02-15, 80101, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2019-01-24 Created: 2018-12-19 Last updated: 2019-02-18
Minakshi, M., Mitchell, D. R. G., Baur, C., Chable, J., Barlow, A. J., Fichtner, M., . . . Ahuja, R. (2019). Phase evolution in calcium molybdate nanoparticles as a function of synthesis temperature and its electrochemical effect on energy storage. NANOSCALE ADVANCES, 1(2), 565-580
Open this publication in new window or tab >>Phase evolution in calcium molybdate nanoparticles as a function of synthesis temperature and its electrochemical effect on energy storage
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2019 (English)In: NANOSCALE ADVANCES, ISSN 2516-0230, Vol. 1, no 2, p. 565-580Article in journal (Refereed) Published
Abstract [en]

The design of a suitable electrode is an essential and fundamental research challenge in the field of electrochemical energy storage because the electronic structures and morphologies determine the surface redox reactions. Calcium molybdate (CaMoO4) was synthesized by a combustion route at 300 degrees C and 500 degrees C. We describe new findings on the behaviour of CaMoO4 and evaluate the influence of crystallinity on energy storage performance. A wide range of characterization techniques was used to obtain detailed information about the physical and morphological characteristics of CaMoO4. The characterization results enable the phase evolution as a function of the electrode synthesis temperature to be understood. The crystallinity of the materials was found to increase with increasing temperature but with no second phases observed. Molecular dynamics simulation of electronic structures correlated well with the experimental findings. These results show that to enable faster energy storage and release for a given surface area, amorphous CaMoO4 is required, while larger energy storage can be obtained by using crystalline CaMoO4. CaMoO4 has been evaluated as a cathode material in classical lithium-ion batteries recently. However, determining the surface properties in a sodium-ion system experimentally, combined with computational modelling to understand the results has not been reported. The superior electrochemical properties of crystalline CaMoO4 are attributed to its morphology providing enhanced Na+ ion diffusivity and electron transport. However, the presence of carbon in amorphous CaMoO4 resulted in excellent rate capability, suitable for supercapacitor applications.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-393014 (URN)10.1039/c8na00156a (DOI)000479170600016 ()
Funder
Swedish Research CouncilCarl Tryggers foundation
Available from: 2019-09-19 Created: 2019-09-19 Last updated: 2019-09-19Bibliographically approved
Chakraborty, S., Banerjee, A., Watcharatharapong, T., Araujo, R. B. & Ahuja, R. (2018). Current computational trends in polyanionic cathode materials for Li and Na batteries. Journal of Physics: Condensed Matter, 30(28), Article ID 283003.
Open this publication in new window or tab >>Current computational trends in polyanionic cathode materials for Li and Na batteries
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2018 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 30, no 28, article id 283003Article, review/survey (Refereed) Published
Abstract [en]

A long-standing effort has been devoted for the development of high energy density cathodes both for Li-and Na-ion batteries (LIBs and SIBs). The scientific communities in battery research primarily divide the Li- and Na-ion cathode materials into two categories: layered oxides and polyanionic compounds. Researchers are trying to improve the energy density of such materials through materials screening by mixing the transition metals or changing the concentration of Li or Na in the polyanionic compounds. Due to the fact that there is more stability in the polyanionic frameworks, batteries based on these materials mostly provide a prolonged cycling life as compared to the layered oxide materials. Nevertheless, the bottleneck for such compounds is the weight penalty from polyanionic groups that results into the lower capacity. The anion engineering could be considered as an essential way out to design such polyanionic compounds to resolve this issue and to fetch improved cathode performance. In this topical review we present a systematic overview of the polyanionic cathode materials used for LIBs and SIBs. We will also present the computational methodologies that have become significantly relevant for battery research. We will make an attempt to provide the theoretical insight with a current development in sulfate (SO4), silicate (SiO4) and phosphate (PO4) based cathode materials for LIBs and SIBs. We will end this topical review with the future outlook, that will consist of the next generation organic electrode materials, mainly based on conjugated carbonyl compounds.

Keywords
Li-ion batteries, Na-ion batteries, energy storage, polyanionic cathode materials, organic cathode materials, DFT investigation
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-368909 (URN)10.1088/1361-648X/aac62d (DOI)000436088400001 ()29932053 (PubMedID)
Funder
Swedish Research CouncilCarl Tryggers foundation StandUp
Available from: 2018-12-10 Created: 2018-12-10 Last updated: 2019-04-05Bibliographically approved
Banerjee, A., Araujo, R. B., Sjödin, M. & Ahuja, R. (2018). Identifying the tuning key of disproportionation redox reaction in terephthalate: A Li-based anode for sustainable organic batteries. Nano Energy, 47, 301-308
Open this publication in new window or tab >>Identifying the tuning key of disproportionation redox reaction in terephthalate: A Li-based anode for sustainable organic batteries
2018 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 47, p. 301-308Article in journal (Refereed) Published
Abstract [en]

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.

Keywords
Li-ion organic battery, Lithium terephthalate, Disproportionation, Redox potential
National Category
Physical Chemistry Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-354095 (URN)10.1016/j.nanoen.2018.02.038 (DOI)000430057000031 ()
Funder
Swedish Research Council, 2016-06014
Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2018-12-19Bibliographically approved
Djouambi, N., Bougheloum, C., Messalhi, A., Bououdina, M., Banerjee, A., Chakraborty, S. & Ahuja, R. (2018). New Concept on Photocatalytic Degradation of Thiophene Derivatives: Experimental and DFT Studies. The Journal of Physical Chemistry C, 122(27), 15646-15651
Open this publication in new window or tab >>New Concept on Photocatalytic Degradation of Thiophene Derivatives: Experimental and DFT Studies
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 27, p. 15646-15651Article in journal (Refereed) Published
Abstract [en]

In this study, the photocatalytic degradation of seven sulfur compounds (2-methylthiophene, 3-methylthiophene, 2-phenylthiophene, 3-phenylthiophene, 2,5-diphenylthiophene, 2-(2-thienyl) pyridine, and 2-(3-thienyl) pyridine in semiaqueous medium are compared to thiophene. The apparent-reaction-rate constant (k) is found to decrease in the following order: 2,5-diphenylthiophene > 2-(2-thienyl) pyridine > 2-penhylthiophene methylthiophene > 3-penhylthiophene > 2-methylthiophene > 2-(3-thienyl) pyridine > 3-thiophene. From the data obtained by UV light absorption (lambda(max)) measurements and electronic structure calculations (frontier orbitals energy, global hardness, and global softness), the kinetic parameters of the reaction have been determined. Among the studied compounds, thiophene with a high lambda(max) and low calculated LUMO-HOMO gap energy has showed higher activity under UV irradiation. Interestingly, a lower activity is observed with low lambda(max) and high LUMO-HOMO gap energy. This demonstrates, for the first time, that the reactivity depends essentially on the thermodynamic stability of the sulfur compound rather than on the nature or the position of the substituent on the ring.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-362014 (URN)10.1021/acs.jpcc.8b03640 (DOI)000439003600063 ()
Funder
Swedish Research CouncilCarl Tryggers foundation
Available from: 2018-10-05 Created: 2018-10-05 Last updated: 2018-10-05Bibliographically approved
Banerjee, A., Chakraborty, S., Jena, N. K. & Ahuja, R. (2018). Scrupulous Probing of Bifunctional Catalytic Activity of Borophene Monolayer: Mapping Reaction Coordinate with Charge Transfer. ACS Applied Energy Materials, 1(8), 3571-3576
Open this publication in new window or tab >>Scrupulous Probing of Bifunctional Catalytic Activity of Borophene Monolayer: Mapping Reaction Coordinate with Charge Transfer
2018 (English)In: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 1, no 8, p. 3571-3576Article in journal (Refereed) Published
Abstract [en]

We have envisaged the hydrogen evolution and oxygen evolution reactions (HER and OER) on two-dimensional (2D) noble metal free borophene monolayer based on first-principles electronic structure calculations. We have investigated the effect of Ti functionalization on borophene monolayer from the perspective of HER and OER activities enhancement. We have probed the activities based on the reaction coordinate, which is conceptually related to the adsorption free energies of the intermediates of HER and OER, as well as from the vibrational frequency analysis with the corresponding charge transfer mechanism between the surface and the adsorbate. Ti-functionalized borophene has emerged as a promising material for HER and OER mechanisms. We believe that our probing method, based on reaction coordinate coupled with vibrational analysis that has been validated by the charge transfer mechanism, would certainly become as a robust prediction route for HER and OER mechanisms in coming days.

Keywords: borophene; hydrogen evolution reaction; oxygen evolution reaction; reaction coordinate; vibrational frequency

Keywords
borophene; hydrogen evolution reaction; oxygen evolution reaction; reaction coordinate; vibrational frequency
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-369691 (URN)10.1021/acsaem.8b00813 (DOI)000458706400007 ()
Funder
Carl Tryggers foundation StandUpSwedish Research Council
Available from: 2018-12-16 Created: 2018-12-16 Last updated: 2019-03-07Bibliographically approved
Zhao, X., Hu, J., Wu, B., Banerjee, A., Chakraborty, S., Feng, J., . . . Chen, Z. (2018). Simultaneous enhancement in charge separation and onset potential for water oxidation in a BiVO4 photoanode by W-Ti codoping. Journal of Materials Chemistry A, 6(35), 16965-16974
Open this publication in new window or tab >>Simultaneous enhancement in charge separation and onset potential for water oxidation in a BiVO4 photoanode by W-Ti codoping
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2018 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 35, p. 16965-16974Article in journal (Refereed) Published
Abstract [en]

Efficient charge separation of photo-generated electrons and holes is critical to achieve high solar to hydrogen conversion efficiency in photoelectrochemical (PEC) water splitting. N-type doping is generally used to improve the conductivity by increasing the majority carrier density and enhance the charge separation in the photoanode. However, minority carrier transport is also very important in the process of charge separation, especially in materials that possess inadequate minority carrier mobility. Herein, we take a BiVO4 PEC water splitting cell as an example to demonstrate how to analyze the limiting factor and to formulate the corresponding solutions to improve the hole mobility. The benefits and problems caused by n-type doping (W-doping here) of BiVO4 are analyzed. Codoping with Ti further enhances the charge separation by improving the hole transport and leads to a cathodic shift of the photocurrent onset potential. A high charge separation efficiency (79% at 1.23 V-RHE) in a compact BiVO4 photoanode has been achieved without any nanostructure formation. Theoretical results show that W-Ti codoping has decreased the hole polaron hopping activation energy by 11.5% compared with mono-W doping, and this has resulted in a hole mobility increase by 29%. The calculated adsorption energy and reaction Gibbs free energies indicate that the Ti site is energetically more favorable for water splitting. Moreover, the Ti site possesses a lower overpotential in the W-Ti codoped sample compared with the mono-W doped sample. The current study indicates that in order to improve the solar energy conversion efficiency, there should be a balanced charge transport of both majority and minority charge carriers. This can be achieved by simply choosing appropriate codoping elements.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Physical Chemistry Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-366730 (URN)10.1039/c8ta05491f (DOI)000445218000025 ()
Funder
Swedish Research CouncilSwedish Energy Agency
Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-19Bibliographically approved
Almeida, R., Banerjee, A., Chakraborty, S., Almeida, J. & Ahuja, R. (2018). Theoretical Evidence behind Bifunctional Catalytic Activity in Pristine and Functionalized Al2C Monolayers. ChemPhysChem, 19(1), 148-152
Open this publication in new window or tab >>Theoretical Evidence behind Bifunctional Catalytic Activity in Pristine and Functionalized Al2C Monolayers
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2018 (English)In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 19, no 1, p. 148-152Article in journal (Refereed) Published
Abstract [en]

First principles electronic structure calculations based on the density functional theory (DFT) framework are performed to investigate hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) on two-dimensional Al2C monolayers. In addition to the pristine Al2C monolayer, monolayers doped with Nitrogen (N), Phosphorous (P), Boron (B), and Sulphur (S) are also investigated. After determining the individual adsorption energy of hydrogen and oxygen on the different functionalized Al2C monolayers, the adsorption free energies are predicted for each of the functionalized monolayers in order to assess their suitability for HER or OER. The density of states and optical absorption spectra calculations along with the work function of the functionalized Al2C monolayers enable us to gain a profound understanding of the electronic structure for the individual system and their relation to the water splitting mechanism.

Keywords
adsorption free energy, Al2C monolayer, bifunctional catalysis, density functional calculations, doping
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-341495 (URN)10.1002/cphc.201700768 (DOI)000419338600020 ()28925531 (PubMedID)
Note

De 2 första författarna delar förstaförfattarskapet.

Available from: 2018-02-19 Created: 2018-02-19 Last updated: 2018-12-19Bibliographically approved
Araujo, R. B., Banerjee, A., Panigrahi, P., Yang, L., Sjödin, M., Strömme, M., . . . Ahuja, R. (2017). Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries. Physical Chemistry, Chemical Physics - PCCP, 19(4), 3307-3314
Open this publication in new window or tab >>Assessing Electrochemical Properties of Polypyridine and Polythiophene for Prospective Application in Sustainable Organic Batteries
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2017 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 4, p. 3307-3314Article in journal (Refereed) Published
Abstract [en]

Conducting polymers are being considered promising candidates for sustainable organic batteries mainly due to their fast electron transport properties and high recyclability. In this work, key properties of polythiophene and polypyridine have been assessed through a combined theoretical and experimental study focusing on such applications. A theoretical protocol has been developed to calculate redox potentials in solution within the framework of the density functional theory and using continuous solvation models. Here, the evolution of the electrochemical properties of solvated oligomers as a function of the length of the chain is analyzed and then the polymer properties are estimated via linear regressions using ordinary least square. The predicted values were verified against our electrochemical experiments. This protocol can now be employed to screen a large database of compounds in order to identify organic electrodes with superior properties.

National Category
Nano Technology
Research subject
Engineering Science with specialization in Nanotechnology and Functional Materials
Identifiers
urn:nbn:se:uu:diva-311276 (URN)10.1039/C6CP07435A (DOI)000394940400071 ()28091636 (PubMedID)
Funder
Swedish Foundation for Strategic Research Swedish Energy AgencyStandUpSwedish Research Council
Available from: 2016-12-22 Created: 2016-12-22 Last updated: 2018-12-19Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3548-133x

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