Pub Date : 2020-12-10DOI: 10.1142/s2251237320500045
M. Soni, M. Saleem, A. Mishra
The well-known ferroelectric and dielectric materials based on barium titanate (BaTiO3) with the compositional formula Ba[Formula: see text]AEMxTiO3 [[Formula: see text] and AEM (alkaline earth metal) [Formula: see text] Ca and Sr] denoted as BTO, BCTO and BSTO are reported in this work. The solid-state reaction method was used to synthesize these titanates. The as-synthesized samples were characterized for structural elucidation via X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Raman inelastic scattering, energy dispersive analysis of X-rays (EDAX) and field emission scanning electron microscopy (FESEM). In addition to this, the samples were studied for optical bandgap, dielectric constant, dielectric loss, ac conductivity and polarization ([Formula: see text]–[Formula: see text]) studies. The XRD data analysis revealed that all the samples have acquired a tetragonal structure (P4mm) and are single phased. The Rietveld refinement of Ba[Formula: see text]Ca[Formula: see text]TiO3 confirms XRD results. In FTIR spectra, the absorption modes appearing at about 400[Formula: see text]cm[Formula: see text] and 500[Formula: see text]cm[Formula: see text] are attributes of the vibration of Ti–O bonds and Ba–O bonds, confirming the formation of desired samples. The appearance of the Raman mode of vibration at about 310[Formula: see text]cm[Formula: see text] is an indication of the tetragonal phase. FESEM micrographs of Ba[Formula: see text]Ca[Formula: see text]TiO3 reveal grain growth in the range of about 1[Formula: see text][Formula: see text]m and its EDAX spectrum confirms the composition of the sample. The optical bandgap was found to be 3.35[Formula: see text]eV, 3.1[Formula: see text]eV and 2.65[Formula: see text]eV for pristine, Ca[Formula: see text]- and Sr[Formula: see text]-doped BaTiO3, respectively. Frequency-dependent dielectric studies infer the samples to be extremely good dielectrics in nature with very low loss values. Polarization against a field at 1000[Formula: see text]V witnesses the samples to exhibit low polarization effects with lossy character. The dielectric and [Formula: see text]–[Formula: see text] behavior of Ba[Formula: see text]Sr[Formula: see text]TiO3 was found exceptional among all the reported titanates.
{"title":"A-Site Substituted BaTiO3: Analysis of Structural, Optical, Ferroelectric and Dielectric Nature","authors":"M. Soni, M. Saleem, A. Mishra","doi":"10.1142/s2251237320500045","DOIUrl":"https://doi.org/10.1142/s2251237320500045","url":null,"abstract":"The well-known ferroelectric and dielectric materials based on barium titanate (BaTiO3) with the compositional formula Ba[Formula: see text]AEMxTiO3 [[Formula: see text] and AEM (alkaline earth metal) [Formula: see text] Ca and Sr] denoted as BTO, BCTO and BSTO are reported in this work. The solid-state reaction method was used to synthesize these titanates. The as-synthesized samples were characterized for structural elucidation via X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Raman inelastic scattering, energy dispersive analysis of X-rays (EDAX) and field emission scanning electron microscopy (FESEM). In addition to this, the samples were studied for optical bandgap, dielectric constant, dielectric loss, ac conductivity and polarization ([Formula: see text]–[Formula: see text]) studies. The XRD data analysis revealed that all the samples have acquired a tetragonal structure (P4mm) and are single phased. The Rietveld refinement of Ba[Formula: see text]Ca[Formula: see text]TiO3 confirms XRD results. In FTIR spectra, the absorption modes appearing at about 400[Formula: see text]cm[Formula: see text] and 500[Formula: see text]cm[Formula: see text] are attributes of the vibration of Ti–O bonds and Ba–O bonds, confirming the formation of desired samples. The appearance of the Raman mode of vibration at about 310[Formula: see text]cm[Formula: see text] is an indication of the tetragonal phase. FESEM micrographs of Ba[Formula: see text]Ca[Formula: see text]TiO3 reveal grain growth in the range of about 1[Formula: see text][Formula: see text]m and its EDAX spectrum confirms the composition of the sample. The optical bandgap was found to be 3.35[Formula: see text]eV, 3.1[Formula: see text]eV and 2.65[Formula: see text]eV for pristine, Ca[Formula: see text]- and Sr[Formula: see text]-doped BaTiO3, respectively. Frequency-dependent dielectric studies infer the samples to be extremely good dielectrics in nature with very low loss values. Polarization against a field at 1000[Formula: see text]V witnesses the samples to exhibit low polarization effects with lossy character. The dielectric and [Formula: see text]–[Formula: see text] behavior of Ba[Formula: see text]Sr[Formula: see text]TiO3 was found exceptional among all the reported titanates.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48453380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-08DOI: 10.1142/s2251237320300028
K. Das, Soumyajit Roy
Multi-component hybrid materials are intriguing. They have the potential to act as a platform to manifest the properties of their components. In this review, we discuss the catalytic applications of few such hybrids that are based on oxometalates (OMs). Due to the structural flexibility and enormous properties, OMs are unrivaled in the field of catalysis. Thus, here we primarily focus on the synthesis and catalysis of such OM-based hybrids. The present overview shows that it is possible to improve the catalytic property of bare oxometalates and even that of their soft-matter state namely soft-oxometalates (SOMs) through rational choice of organic ligand and oxometalates.
{"title":"Oxometalate- and Soft-Oxometalate-Based Hybrid Materials: From Synthesis to Catalytic Applications","authors":"K. Das, Soumyajit Roy","doi":"10.1142/s2251237320300028","DOIUrl":"https://doi.org/10.1142/s2251237320300028","url":null,"abstract":"Multi-component hybrid materials are intriguing. They have the potential to act as a platform to manifest the properties of their components. In this review, we discuss the catalytic applications of few such hybrids that are based on oxometalates (OMs). Due to the structural flexibility and enormous properties, OMs are unrivaled in the field of catalysis. Thus, here we primarily focus on the synthesis and catalysis of such OM-based hybrids. The present overview shows that it is possible to improve the catalytic property of bare oxometalates and even that of their soft-matter state namely soft-oxometalates (SOMs) through rational choice of organic ligand and oxometalates.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47907416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-11-28DOI: 10.1142/s2251237320500057
S. Thiyagarajan, M. Vallejo, P. Ceron, C. Gómez-Solis, C. Wiechers, E. Montes, R. Navarro, M. Sosa
Lithium tetraborate (LTB) was doped with copper (0.1%) to enhance the LTB thermoluminescent (TL) properties. A graphene reducing atmosphere was used to increase the vacancies of oxygen in the crystalline structure. LTB:Cu [Formula: see text] PTFE (polytetrafluoroethylene) pellets were prepared by mixing the Li2B4O7:Cu with PTFE in a 4:1 ratio. The obtained materials were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Crystals of Li2B4O7 with the average size of 134[Formula: see text]nm were obtained. The presence of copper was confirmed by SEM. The TL response of LTB:Cu PTFE pellets was studied with [Formula: see text] radiation by using a [Formula: see text]Co source. TTL response shows a linear behavior depending on the radiation dose. The effect of annealing time on TL glow curve was analyzed from 2[Formula: see text]h to 10[Formula: see text]h by irradiating with X-rays. The effect of mass on the TL response was studied varying the mass of the sample from 10[Formula: see text]mg to 50[Formula: see text]mg. From various heating rate studies, it was observed that the TL intensity increased when heating rate was gradually increased. The kinetic parameters were calculated by using computer deconvolution methods. The dosimetric property results showed that this material could have good potential application in a radiation dosimeter for radiation therapy treatment in the medical field.
{"title":"Thermoluminescence of Cu-Doped Li2B4O7+PTFE Annealed by Graphene Exposed to X-Rays and Gamma Radiation","authors":"S. Thiyagarajan, M. Vallejo, P. Ceron, C. Gómez-Solis, C. Wiechers, E. Montes, R. Navarro, M. Sosa","doi":"10.1142/s2251237320500057","DOIUrl":"https://doi.org/10.1142/s2251237320500057","url":null,"abstract":"Lithium tetraborate (LTB) was doped with copper (0.1%) to enhance the LTB thermoluminescent (TL) properties. A graphene reducing atmosphere was used to increase the vacancies of oxygen in the crystalline structure. LTB:Cu [Formula: see text] PTFE (polytetrafluoroethylene) pellets were prepared by mixing the Li2B4O7:Cu with PTFE in a 4:1 ratio. The obtained materials were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Crystals of Li2B4O7 with the average size of 134[Formula: see text]nm were obtained. The presence of copper was confirmed by SEM. The TL response of LTB:Cu PTFE pellets was studied with [Formula: see text] radiation by using a [Formula: see text]Co source. TTL response shows a linear behavior depending on the radiation dose. The effect of annealing time on TL glow curve was analyzed from 2[Formula: see text]h to 10[Formula: see text]h by irradiating with X-rays. The effect of mass on the TL response was studied varying the mass of the sample from 10[Formula: see text]mg to 50[Formula: see text]mg. From various heating rate studies, it was observed that the TL intensity increased when heating rate was gradually increased. The kinetic parameters were calculated by using computer deconvolution methods. The dosimetric property results showed that this material could have good potential application in a radiation dosimeter for radiation therapy treatment in the medical field.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251237320500057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45484392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-03DOI: 10.1142/s2251237320300016
Matej Sebek, A. Elbana, A. Nemati, Jisheng Pan, Z. Shen, M. Hong, X. Su, N. Thanh, J. Teng
The inherent thinness of two-dimensional 2D materials limits their efficiency of light-matter interactions and the high loss of noble metal plasmonic nanostructures limits their applicability. Thus...
{"title":"Hybrid Plasmonics and Two-Dimensional Materials: Theory and Applications","authors":"Matej Sebek, A. Elbana, A. Nemati, Jisheng Pan, Z. Shen, M. Hong, X. Su, N. Thanh, J. Teng","doi":"10.1142/s2251237320300016","DOIUrl":"https://doi.org/10.1142/s2251237320300016","url":null,"abstract":"The inherent thinness of two-dimensional 2D materials limits their efficiency of light-matter interactions and the high loss of noble metal plasmonic nanostructures limits their applicability. Thus...","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251237320300016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43243069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.1142/s2251237320500021
L. Rani
A three-phase-lag model of a homogeneous thermally conducting orthorhombic thermoviscoelastic material under the effect of the dependence of reference temperature on all elastic and thermal parameters is investigated. The Laplace and Fourier transform and eigenvalue approach techniques are used to solve the resulting nondimensional coupled equations. As an application of the problem, harmonically varying and sinusoidal pulse functions are considered. Numerical results for the field quantities are given in the physical domain and illustrated graphically. Comparisons are made for thermoviscoelastic temperature dependent, thermoviscoelastic and thermoelastic materials, respectively, for different values of time, for temperature gradient boundary.
{"title":"Elastodynamic Response of a Three-Phase-Lag Model of Orthorhombic Thermoviscoelastic Material with Reference Temperature Dependent Properties","authors":"L. Rani","doi":"10.1142/s2251237320500021","DOIUrl":"https://doi.org/10.1142/s2251237320500021","url":null,"abstract":"A three-phase-lag model of a homogeneous thermally conducting orthorhombic thermoviscoelastic material under the effect of the dependence of reference temperature on all elastic and thermal parameters is investigated. The Laplace and Fourier transform and eigenvalue approach techniques are used to solve the resulting nondimensional coupled equations. As an application of the problem, harmonically varying and sinusoidal pulse functions are considered. Numerical results for the field quantities are given in the physical domain and illustrated graphically. Comparisons are made for thermoviscoelastic temperature dependent, thermoviscoelastic and thermoelastic materials, respectively, for different values of time, for temperature gradient boundary.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42639681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.1142/s225123732050001x
Ruochen Sun, H. Qi, Pingan Liu, Fangwei Lv
In this paper, thermal diffusion states of pure diethyl ether and its mixture with cellulose dinitrate tripolymer were uncovered by LAMMPS-based Molecular Dynamic (MD) simulations. Those MD simulations were generally performed through specified ReaxFF reactive force field to obtain the properties of the chemical system such as molecular energy, density, mean square displacement (MSD) and molecular coordinate. The result of MD simulations presented the clear superheating phenomenon of pure liquid diethyl ether system in the studied environment. The obtained phase transition point was much higher than the reported one. The deviation between two temperatures was about 132.369[Formula: see text]K. It was also demonstrated that the transition process was associated with the sharp increment of potential energy, volume, diffusion coefficient and cohesive energy. However, the split of these diethyl ether molecules was not uniform. The cluster-like transition state was observed before the end of the vaporing process (460[Formula: see text]K). As for the addition of cellulose dinitrate tripolymer, these molecules were not agglomerated in the simulated organic mixture. However, the diffusion of cellulose dinitrate tripolymer was much weaker than those diethyl ether molecules. While the concentration of cellulose dinitrate tripolymer was higher, molecular interactions of this organic mixture were consequently improved, and this further limited the diffusion behavior of the entire chemical system. It could be concluded that the diffusion behavior of the entire organic system was decreased with more amount of cellulose dinitrate tripolymer molecules.
{"title":"Molecular Dynamic Simulations of Diethyl Ether and its Mixture with Cellulose Dinitrate Tripolymer Molecules for their Thermal Diffusion Behaviors","authors":"Ruochen Sun, H. Qi, Pingan Liu, Fangwei Lv","doi":"10.1142/s225123732050001x","DOIUrl":"https://doi.org/10.1142/s225123732050001x","url":null,"abstract":"In this paper, thermal diffusion states of pure diethyl ether and its mixture with cellulose dinitrate tripolymer were uncovered by LAMMPS-based Molecular Dynamic (MD) simulations. Those MD simulations were generally performed through specified ReaxFF reactive force field to obtain the properties of the chemical system such as molecular energy, density, mean square displacement (MSD) and molecular coordinate. The result of MD simulations presented the clear superheating phenomenon of pure liquid diethyl ether system in the studied environment. The obtained phase transition point was much higher than the reported one. The deviation between two temperatures was about 132.369[Formula: see text]K. It was also demonstrated that the transition process was associated with the sharp increment of potential energy, volume, diffusion coefficient and cohesive energy. However, the split of these diethyl ether molecules was not uniform. The cluster-like transition state was observed before the end of the vaporing process (460[Formula: see text]K). As for the addition of cellulose dinitrate tripolymer, these molecules were not agglomerated in the simulated organic mixture. However, the diffusion of cellulose dinitrate tripolymer was much weaker than those diethyl ether molecules. While the concentration of cellulose dinitrate tripolymer was higher, molecular interactions of this organic mixture were consequently improved, and this further limited the diffusion behavior of the entire chemical system. It could be concluded that the diffusion behavior of the entire organic system was decreased with more amount of cellulose dinitrate tripolymer molecules.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s225123732050001x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49380949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-01DOI: 10.1142/s2251237320500033
A. Abouelregal
(1) In the present work, a new modified thermoelasticity theory with fractional order has been constructed based on fractional calculus and Taylor series expansion of time-fractional order. The models of fractional thermoelasticity proposed by Sherief et al. [H. H. Sherief, A. M. A. El-Sayed and A. M. Abd El-Latief, Int. J. Solids Struct. 47, 269 (2010)], Ezzat [M. A. Ezzat, Phys. B 406, 30 (2011)] and Lord and Shulman with one relaxation time [H. W. Lord and Y. H. Shulman, J. Mech. Phys. Solids 15(5), 299 (1967)] as well as coupled thermoelasticity [M. A. Biot, J. Appl. Phys. 27, 240 (1956)] follow as limiting cases. This modified model is applied to an infinitely long annular cylinder. The inner and outer surfaces of the cylinder are traction free and subjected to known surrounding temperatures. Laplace transform technique will be used to get the solutions of all physical quantities. Some comparisons are shown in figures and tables to assess the effects of the fractional-order parameters in the studied fields. Results of some earlier researchers have been deduced from the current formulation. Finally, a conclusion about the new modified model has been promoted according to the analysis and numerical results.
（1） 在分数阶微积分和时间分数阶的泰勒级数展开的基础上，构造了一个新的改进的分数阶热弹性理论。Sherief等人【H.H.Sherief，A.M.A.El Sayed和A.M.Abd El Latief，Int.J.Solids Struct.47269（2010）】、Ezzat【M.A.Ezzat，Phys.B 406，30（2011）】和Lord和Shulman提出的具有一个弛豫时间的分数热弹性模型【H.W.Lord和Y.H.Shulman，J.Mech.Phys.Solids 15（5），299（1967）】以及耦合热弹性【M.A.Biot，J。Appl。Phys。27240（1956）]作为限制性情况。该改进模型应用于无限长环形圆柱体。气缸的内表面和外表面无牵引力，并承受已知的周围温度。拉普拉斯变换技术将被用来得到所有物理量的解。图和表中显示了一些比较，以评估分数阶参数在所研究领域中的影响。一些早期研究人员的结果已经从目前的公式中推导出来。最后，根据分析和数值结果，对新的修正模型提出了结论。
{"title":"A Modified Law of Heat Conduction of Thermoelasticity with Fractional Derivative and Relaxation Time","authors":"A. Abouelregal","doi":"10.1142/s2251237320500033","DOIUrl":"https://doi.org/10.1142/s2251237320500033","url":null,"abstract":"(1) In the present work, a new modified thermoelasticity theory with fractional order has been constructed based on fractional calculus and Taylor series expansion of time-fractional order. The models of fractional thermoelasticity proposed by Sherief et al. [H. H. Sherief, A. M. A. El-Sayed and A. M. Abd El-Latief, Int. J. Solids Struct. 47, 269 (2010)], Ezzat [M. A. Ezzat, Phys. B 406, 30 (2011)] and Lord and Shulman with one relaxation time [H. W. Lord and Y. H. Shulman, J. Mech. Phys. Solids 15(5), 299 (1967)] as well as coupled thermoelasticity [M. A. Biot, J. Appl. Phys. 27, 240 (1956)] follow as limiting cases. This modified model is applied to an infinitely long annular cylinder. The inner and outer surfaces of the cylinder are traction free and subjected to known surrounding temperatures. Laplace transform technique will be used to get the solutions of all physical quantities. Some comparisons are shown in figures and tables to assess the effects of the fractional-order parameters in the studied fields. Results of some earlier researchers have been deduced from the current formulation. Finally, a conclusion about the new modified model has been promoted according to the analysis and numerical results.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251237320500033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49485322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-26DOI: 10.1142/s2251237319500060
S. Islam, Syed Abdus Satter, N. Khatun, M. S. Hossain, S. Farhad, P. Bała, S. Tabassum, A. Siddika
Bismuth and Yttrium co-doped Barium Titanate (BaTiO3) ceramics with the general formula (Ba[Formula: see text]BiX) (YxTi[Formula: see text]) O3 (where [Formula: see text], 0.01, 0.03, 0.05) have been synthesized at 1300∘C for 3[Formula: see text]h by the standard solid-state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Impedance Analyzer. Temperature-dependent dielectric properties of the samples were also measured. The XRD result revealed perovskite structure for un-doped and co-doped BaTiO3 with tetragonal phase. However, with increasing doping concentration, a Pseudo cubic phase occurs also confirmed by the twin peaks (002) and (200) of XRD pattern. From SEM micrograph, submicron size particles were observed for all synthesized BaTiO3 samples and exhibit a narrow size distribution with quiet uniform morphology. The crystalline size for un-doped BaTiO3 found was 24.26[Formula: see text]nm, the size decreases (minimum 19.59[Formula: see text]nm for [Formula: see text]) for all compositions of co-doped BaTiO3. Dielectric constant values were apparently high and direct current (DC) resistivity follows a decreasing trend at higher doping concentration. The sample doped with [Formula: see text] shows minimum DC resistivity and maximum dielectric constant among the samples investigated.
{"title":"Investigation of Structural, Dielectric and Electrical Properties of Barium Titanate Ceramics Co-Doped with Bismuth and Yttrium","authors":"S. Islam, Syed Abdus Satter, N. Khatun, M. S. Hossain, S. Farhad, P. Bała, S. Tabassum, A. Siddika","doi":"10.1142/s2251237319500060","DOIUrl":"https://doi.org/10.1142/s2251237319500060","url":null,"abstract":"Bismuth and Yttrium co-doped Barium Titanate (BaTiO3) ceramics with the general formula (Ba[Formula: see text]BiX) (YxTi[Formula: see text]) O3 (where [Formula: see text], 0.01, 0.03, 0.05) have been synthesized at 1300∘C for 3[Formula: see text]h by the standard solid-state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Impedance Analyzer. Temperature-dependent dielectric properties of the samples were also measured. The XRD result revealed perovskite structure for un-doped and co-doped BaTiO3 with tetragonal phase. However, with increasing doping concentration, a Pseudo cubic phase occurs also confirmed by the twin peaks (002) and (200) of XRD pattern. From SEM micrograph, submicron size particles were observed for all synthesized BaTiO3 samples and exhibit a narrow size distribution with quiet uniform morphology. The crystalline size for un-doped BaTiO3 found was 24.26[Formula: see text]nm, the size decreases (minimum 19.59[Formula: see text]nm for [Formula: see text]) for all compositions of co-doped BaTiO3. Dielectric constant values were apparently high and direct current (DC) resistivity follows a decreasing trend at higher doping concentration. The sample doped with [Formula: see text] shows minimum DC resistivity and maximum dielectric constant among the samples investigated.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251237319500060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48889848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-25DOI: 10.1142/s2251237319500047
M. Sajjad, Xu Chen, Chunxin Yu, Linlin Guan, Shuyu Zhang, Yang Ren, Xiaowei Zhou, Zhu Liu
NiCo2S4/CNTs (NCS/CNTs) hybrid nanostructures have been synthesized by a facile one-step solvothermal method with varying content of CNTs. The structure and morphology of the synthesized NCS/CNTs hybrid revealed the formation of platelets anchored on the CNT matrix. When evaluated as electrode materials for supercapacitor, the as-synthesized NCS/CNT-1 hybrid (with 1% of CNT) manifested remarkable specific capacitance of 1690[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 5[Formula: see text]A[Formula: see text]g[Formula: see text]. More importantly, an asymmetric supercapacitor (ASC) assembled based on NCS/CNT-1 as positive electrode and carbon nanotube paper (CNP) as a negative electrode delivered high energy density of 58[Formula: see text]Wh[Formula: see text]kg[Formula: see text] under power density of 8[Formula: see text]kW[Formula: see text]kg[Formula: see text]. Furthermore, the ASC device exhibited high cycling stability and 77.7% of initial specific capacitance retention after 7000 charge–discharge cycles at a current density of 8[Formula: see text]A[Formula: see text]g[Formula: see text]. The large enhancement in the electrochemical performance is attributed to the benefits of the nanostructured architecture, including good mechanical stability, high electrical conductivity as well as buffering for the volume changes during charge–discharge process. These convincing results show that NCS/CNTs hybrid nanostructures are promising electrode materials for high energy density supercapacitors (SCs).
{"title":"High Energy Density Asymmetric Supercapacitor Based on NiCo2S4/CNTs Hybrid and Carbon Nanotube Paper Electrodes","authors":"M. Sajjad, Xu Chen, Chunxin Yu, Linlin Guan, Shuyu Zhang, Yang Ren, Xiaowei Zhou, Zhu Liu","doi":"10.1142/s2251237319500047","DOIUrl":"https://doi.org/10.1142/s2251237319500047","url":null,"abstract":"NiCo2S4/CNTs (NCS/CNTs) hybrid nanostructures have been synthesized by a facile one-step solvothermal method with varying content of CNTs. The structure and morphology of the synthesized NCS/CNTs hybrid revealed the formation of platelets anchored on the CNT matrix. When evaluated as electrode materials for supercapacitor, the as-synthesized NCS/CNT-1 hybrid (with 1% of CNT) manifested remarkable specific capacitance of 1690[Formula: see text]F[Formula: see text]g[Formula: see text] at the current density of 5[Formula: see text]A[Formula: see text]g[Formula: see text]. More importantly, an asymmetric supercapacitor (ASC) assembled based on NCS/CNT-1 as positive electrode and carbon nanotube paper (CNP) as a negative electrode delivered high energy density of 58[Formula: see text]Wh[Formula: see text]kg[Formula: see text] under power density of 8[Formula: see text]kW[Formula: see text]kg[Formula: see text]. Furthermore, the ASC device exhibited high cycling stability and 77.7% of initial specific capacitance retention after 7000 charge–discharge cycles at a current density of 8[Formula: see text]A[Formula: see text]g[Formula: see text]. The large enhancement in the electrochemical performance is attributed to the benefits of the nanostructured architecture, including good mechanical stability, high electrical conductivity as well as buffering for the volume changes during charge–discharge process. These convincing results show that NCS/CNTs hybrid nanostructures are promising electrode materials for high energy density supercapacitors (SCs).","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251237319500047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48628515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-10-25DOI: 10.1142/s2251237319500059
M. Sajjad, A. Iqbal, Muhammad Ibrar Khan, M. Qureshi, Y. Khan
Excellent cycling stability along with a high specific capacitance of the electrode material is the primary requirement for supercapacitor (SC) in recent years. Exceptionally simple and cost-effective solution process is employed for the first time to prepare [Formula: see text]-MnO2/rGO composites, in which KMnO4 content varies from (2[Formula: see text]mg, 4[Formula: see text]mg, 6[Formula: see text]mg and 8[Formula: see text]mg). The morphological analysis showed that [Formula: see text]-MnO2/rGO composites possess nanorod like morphology and were fully covered with rGO sheet. Among all composites, the sample with 6[Formula: see text]mg content of KMnO4 denoted as [Formula: see text]-MnO2/rGO composite (S–3) showed excellent supercapacitive performance with a specific capacitance of 720[Formula: see text]F/g at a current density of 4 A g[Formula: see text] with excellent cycling stability of 93% after 2000 cycles. Furthermore, these nanocomposites showed excellent supercapacitive properties with specific capacitances of 720–498 F/g at the current density of 4 A g[Formula: see text] with cycling stabilities of 71%, 68% and 60%, respectively.
优异的循环稳定性以及电极材料的高比电容是近年来对超级电容器（SC）的主要要求。首次采用异常简单且具有成本效益的溶液工艺制备[式：见正文]-MnO2/rGO复合材料，其中KMnO4含量从（2[式：参见正文]mg、4[式：详见正文]mg，6[式：请见正文]mg和8[式：参阅正文]mg）变化。形态分析表明，[式：见正文]-MnO2/rGO复合材料具有纳米棒状形态，并被rGO片完全覆盖。在所有复合材料中，具有6[式：见正文]mg KMnO4含量的样品（表示为[式：参见正文]-MnO2/rGO复合材料（S–3））在4 a g的电流密度下显示出优异的超级电容性能，比电容为720[式：详见正文]F/g[式：请见正文]，2000次循环后具有93%的优异循环稳定性。此外，这些纳米复合材料显示出优异的超级电容性能，在4 A g的电流密度下，比电容为720–498 F/g[公式：见正文]，循环稳定性分别为71%、68%和60%。
{"title":"MnO2 Nanorods Embedded Reduced Graphene Oxide Nanocomposite with Ultrahigh Specific Capacitance and Excellent Cyclic Stability for High Performance Supercapacitors","authors":"M. Sajjad, A. Iqbal, Muhammad Ibrar Khan, M. Qureshi, Y. Khan","doi":"10.1142/s2251237319500059","DOIUrl":"https://doi.org/10.1142/s2251237319500059","url":null,"abstract":"Excellent cycling stability along with a high specific capacitance of the electrode material is the primary requirement for supercapacitor (SC) in recent years. Exceptionally simple and cost-effective solution process is employed for the first time to prepare [Formula: see text]-MnO2/rGO composites, in which KMnO4 content varies from (2[Formula: see text]mg, 4[Formula: see text]mg, 6[Formula: see text]mg and 8[Formula: see text]mg). The morphological analysis showed that [Formula: see text]-MnO2/rGO composites possess nanorod like morphology and were fully covered with rGO sheet. Among all composites, the sample with 6[Formula: see text]mg content of KMnO4 denoted as [Formula: see text]-MnO2/rGO composite (S–3) showed excellent supercapacitive performance with a specific capacitance of 720[Formula: see text]F/g at a current density of 4 A g[Formula: see text] with excellent cycling stability of 93% after 2000 cycles. Furthermore, these nanocomposites showed excellent supercapacitive properties with specific capacitances of 720–498 F/g at the current density of 4 A g[Formula: see text] with cycling stabilities of 71%, 68% and 60%, respectively.","PeriodicalId":16406,"journal":{"name":"Journal of Molecular and Engineering Materials","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251237319500059","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49371405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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