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Micro encapsulated & form-stable phase change materials for high temperature thermal energy storage

Chloride molten salts are promising candidates for high temperature thermal storage applications, owing to their energy storage density and thermal stability. Nevertheless, the main disadvantage of them is their corrosive behaviour with metal containers, which narrows down the range of applications. Encapsulation is considered a favourable method to prevent the corrosion. In this work, composite thermal storage materials consist of a phase change material (PCM) and a encapsulation material are studied, where the PCM is a mixture of sodium and potassium eutectic salts and the encapsulation material is diatomite. The composite materials which consist of PCMs & encapsulation materials are fabricated using a micro encapsulation method which is a combination of mixing and sintering. After applying the aforementioned method, it is observed that the PCMs are distributed homogeneously in the composite materials. With the help of XRD, it is found that the compounds stay unchanged after the encapsulation process, which indicates that the materials are compatible to each other. In this study, the composite material containing 70 wt% PCM exhibits the most favourable thermal energy storage properties, stability and capsule integrity as it is shown that the latent heat of the aforementioned composite material is observed 179.3 J/g and no significant decline or salt leakage is found after hundreds of heating-cooling cycles.

Remarkable resilience of the formate cage in a multiferroic metal organic framework material: dimethyl ammonium manganese formate (DMAMnF).

Dimethyl ammonium (DMA) metal formate, an important member of the dense metal organic framework (MOF) family, is known to exhibit a low temperature ferroelectric transition, caused by the ordering of the hydrogen bonds. In this study, we probed the effect of pressure on the disordered hydrogen bond and the HCOO- linkers of DMA manganese formate, with the help of XRD, IR and Raman spectroscopic studies up to ∼20 GPa. We observed that though a phase transition was initiated at ∼3.4 GPa, it was complete only by 6 GPa, indicating its first order nature. Beyond 7 GPa, this compound becomes highly disordered and shows an almost amorphous character, indicating a total collapse of the formate network. The reversibility of the initial structure of DMAMnF on the release of pressure from 20 GPa (i.e. from a highly disordered phase) shows the remarkable resilience of the formate cage. At the first crystal to crystal transition at 3.4 GPa, the distortion of the formate cage causes the ordering of the dynamically disordered hydrogen bond, resulting in a rearrangement of the DMA+ cation. Lifting of the mutual exclusivity of the Raman and IR modes (C-H out of plane and O-C-O bending modes) of HCOO- linkers, at this transition, indicates that the high pressure phase may be non-centro-symmetric.

Use of Nanostructured Layered Double Hydroxides as Nanofilters in the Removal of Fe2+ and Ca2+ Ions from Oil Wells

Four new metal‐aluminum layered double hydroxides (LDHs), Mg‐Al(OH)2PO4 (1), Mg‐Al(OH)2PO4PF6 (2), Ca‐Al(OH)2SO4 (3), and Ca‐Al(OH)2PO4PF6 (4), were prepared by the coprecipitation method followed by mild hydrothermal processing at 60°C. Mg2+ and Ca2+ in solution with Al3+ were titrated with NaOH over 3–5 h to yield Mg‐Al and Ca‐Al layered double hydroxides, respectively, incorporating PO43−, PO43−PF6−, and SO42− anions in the interlamellar spaces. The isolated compounds were characterized with the help of XRD, IR, and SEM/EDAX, and their ability to remove scale‐forming ions from the aqueous system was studied with the help of atomic absorption spectroscopy (AAS). The SEM micrographs of Mg‐O‐Al‐OH and Ca‐O‐Al‐OH layers intercalated with PO43− and/or [PO4PF6]4− anions are similar consisting of uniform nanospheres with an average size of 100 nm, while the M‐O‐Al‐OH layer of compound 3, intercalated with SO42− anions, consists of hexagonal nanoplate crystals. In the infrared spectra, the characteristic absorption band for water molecules was observed in all the compounds. The XRD pattern showed that d012 and d104 peaks of M‐Al‐PO4 LDHs corresponding to interplanar spacing of 3.4804 and 2.5504 Å, respectively, shifted to higher 2θ values for the M‐Al‐PO4PF6 system, which indicates a decrease in the interlamellar spacing as PF6− was incorporated along with PO43− anion. The XRD pattern for Ca‐Al‐SO4 LDHs was quite different, showing the presence of low‐angle peaks at 2θ = 11.68 and 14.72°. The results of the column adsorption studies showed that there was a significant removal of Ca2+ by all the compounds under investigation with an efficiency of 84–99%. However, compounds 1 and 2 remove Fe2+ effectively with the efficiency of 98.73 and 99.77%, respectively; compounds 3 and 4 were shown to have little or no effect.

Enhanced DSSCs performance of TiO2 nanostructure by surface passivation layers

Rutile titanium oxide (TiO2) synthesized in copper containers, was spin-coated with different surface passivation layers such as magnesium oxide (MgO), calcium carbonate (CaCO3), zirconium oxide (ZrO2), and tin oxide (SnO2). The deposition of these passivation layers on TiO2 confirmed with the help of XRD and EDX analysis, leads to changes in surface morphology induced by the passivation layers demonstrated by FE-SEM imaging. The highest photoconversion efficiency obtained for TiO2 electrode with MgO passivation layer (6.05%), respective incident photon conversion efficiency was 52%. After introduction of passivation layers on the TiO2 nanostructure, electron lifetime increased from 0.48 ms to 0.65 ms and charge transfer resistance decreased from 36.9 Ω cm (pristine TiO2 electrode) to 20.16 Ω cm (MgO passivation layer).

Synthesis of bimetallic Au-Ag alloyed mesocomposites and their catalytic activity for the reduction of nitroaromatics

Homogeneously dispersed Au-Ag alloyed nanostructures varying from spherical (6–8 nm) to rod shape (aspect ratio ∼15–20 nm) were synthesized within the channels of amine modified mesoporous SBA-15 using post modification. Formation of alloy nanostructures for varying Au-Ag loadings have been supported by XPS and elemental mapping studies. Furthermore, changes in the surface/electronic properties of mesocomposites as a function of increased bimetallic Au:Ag loading have been elucidated with the help of XRD, BET, TEM and XPS studies respectively. It was found that synergism owing to electronic interplay between Au and Ag species concurrently improved the catalytic activity of bimetallic nanocomposites. Among the various monometallic and bimetallic mesocomposites, Au-Ag (5:1)/m-SBA-15 nanocomposites exhibited the best catalytic activity (k = 2.12 × 10−2 min−1 and 3.99 × 10−2 min−1) for the selective reduction of nitrobenzene to aniline and p-nitroacetophenone to p-aminoacetophenone respectively.

Frequency upconversion and fluorescence intensity ratio method in Yb3+-ion-sensitized Gd2O3:Er3+-Eu3+ phosphors for display and temperature sensing

Near infrared (NIR) to visible frequency upconversion emission studies in Er3+-Eu3+/Er3+-Eu3+-Yb3+ co-doped/tri-doped Gd2O3 phosphors prepared by the co-precipitation technique have been explored under 980 nm laser diode radiation. The developed phosphors were characterized with the help of XRD, FE-SEM and FTIR analysis. No upconversion (UC) emission was found in the Eu3+-doped Gd2O3 phosphor. UC emission from Eu3+ ions along with Er3+ ions was observed in Er3+-Eu3+ and Er3+-Eu3+-Yb3+ co-doped/tri-doped phosphors. The UC emission arising from the Er3+ and Eu3+ ions was enhanced several times due to the incorporation of Yb3+ ions. The processes involved in the UC emission were obtained on the basis of the effect of energy transfer/sensitization through the Yb3+ → Er3+ → Eu3+ process. The red/green intensity ratio was improved from 0.16 to 1.50 and 1.01 to 1.50 for Er3+-Eu3+-Yb3+ tri-doped phosphors as compared to the Er3+-doped and Er3+-Yb3+ co-doped phosphors, respectively, at a fixed pump power density. A UC fluorescence intensity ratio (FIR)-based temperature sensing study was performed in the prepared Er3+-Eu3+-Yb3+ tri-doped Gd2O3 phosphors for green upconversion emission bands in the 300 K–443 K temperature range. A maximum sensor sensitivity of about ∼0.0043 K−1 at 300 K was achieved for the synthesized tri-doped phosphors upon excitation with a 980 nm laser diode. The colour coordinates lying in the green–yellow region are invariant, with variation in pump power density and temperature. The observed results support the utility of the prepared tri-doped phosphors in optical temperature sensing, display devices and NIR to visible upconverters.

Selective Oxidation of Cyclohexane Using Graphene Oxide‐Supported Ceria Nanocomposites with Exposed Active {1 0 0} Facets

AbstractThe present study is focused on the synthesis and characterization of ceria loaded graphene oxide (GO) and investigates their catalytic activity on vapor phase selective oxidation of cyclohexane. In this regards, we have synthesized various loading of CeO2 on GO with two different morphology includes nanocrystals and flower‐like, which designated as CeO2(x)/GO (where x= 0, 0.2, 0.4, 0.6, 0.8 and 1.0 wt.%). The physico‐chemical properties of the materials were extensively studied with help of XRD, N2 adsorption desorption (BET), DRUV‐Vis, HRSEM, HRTEM, H2‐TPR and XPS techniques. The crystalline nature of materials were analyzed by XRD, pure ceria shows high crystalline size about 15. 3 nm compared to others. Surface area of synthesized materials has been obtained with help of N2 adsorption desorption analysis, pure ceria and graphene oxide shows surface area about 93 and 574 m2/g, respectively. XPS and DRUV‐Vis spectra were confirms the presence of enormous Ce3+ ions in the lattice. The presence of nanocrystals and flower‐like morphology of CeO2(x)/GO were confirmed by HRSEM images. HRTEM images were clearly illustrated that the presence of dominant active {1 0 0} facets in flower‐like CeO2/GO than that of nanocrystalline morphology. The catalytic activity of materials has been evaluated on selective oxidation of cyclohexane using air as a green oxidant. The key reaction parameters were varied to study the stability, activity and selectivity of the catalysts. The activity of the catalysts is correlated with their physico‐chemical properties, and these results concluded that suitable amount of ceria and it's flower‐like morphology on GO is essential for selective oxidation of cyclohexane at low temperature (180 °C) compared to nanocrystalline morphology. Hence, flower‐like CeO2(0.4)/GO is a most suitable catalyst for high conversion (90%) of cyclohexane into cyclohexanone with 74% selectivity due to occurrence of enormous {1 0 0} facet and Ce3+.

Modification of Nano Spherical-Like MnO<sub>x</sub>/TiO<sub>2</sub> Catalysts with F-Doped

A series of spherical-like MnOx/TiO2 catalysts with F-doped were prepared by using sol-gel method and investigated for low-temperature selective catalytic reduction (SCR) of NOx with NH3 at the temperature ranging from 100 °C to 200 °C. The 0.07Ce-MnOx/TiO2 catalyst shows the highest activity and yields 95% NO conversion at 200 °C. With the help of XRD, TGA, H2-TPR, NH3-TPD, BET and TEM, the structures and properties of the catalysts were characterized. The results show that it is a fine modifier for TiO2 support with appropriate amounts of F doping, and F ions can enter into TiO2 lattice, reducing the formation of rutile TiO2 and the crystallization of MnOx. However, MnTiO3 was generated in the catalysts with excess F doping. This would cause larger diameter of spherical particle and smaller surface area. But the amounts of the surface acid sites increased, and the reduction ability of catalysts was enhanced, which is beneficial for catalytic activity of the catalysts.

Experimental interaction of hydrothermal Na-Cl solution with fracture surfaces of geothermal reservoir sandstone of the Upper Rhine Graben

The Upper Rhine Graben (URG) is a Tertiary rift structure in central Europe offering favorable conditions for geothermal energy utilization. Relatively high heat flow combines with sufficiently high permeability of the hydrothermal reservoirs. One of the target stratigraphic levels is the lower Triassic sandstone formation (Buntsandstein), where hot water resources at temperatures up to 250 °C can be utilized. Extensional neotectonics and hydraulic stimulation form new fracture surfaces in the reservoir rocks (enhanced geothermal system, EGS). The exposed fresh rock fracture surface reacts with the highly saline reservoir brines (Na-Cl up to 200 g l−1) with consequences for the permeability of the reservoir.In order to better understand the dynamic evolution of fault systems caused by fluid-rock interaction, we conducted batch-type experiments in a stirred autoclave system and reacted arkosic sandstone with synthetic 2 molal Na-Cl solution at temperatures of 200 °C and 260 °C. After 45–55 days reaction time altered rock samples were compared with the starting material and the geochemical-mineralogical processes were deduced with the help of XRD, SEM methods and EMP measurements. Fluid compositions were examined by ICP-MS, ICP-OES and IC.The arkosic sandstones show a surprisingly high reactivity during the experiments. Quartz grain surfaces show deep dissolution features and all reaction fluids were saturated with respects to quartz. Illite and kaolinite from the primary sandstone cementation completely dissolved from the sample surface. Perfectly euhedral crystals of metastable analcime formed during the experiment as separate crystals on quartz, as groups or clusters and as surface covering mats. The overall net transfer process dissolves quartz + illite + kaolinite ± K-feldspar and precipitates analcime + chlorite ± albite. The process is accompanied by a total volume increase of the solids of 20–30 vol%. K-feldspar dissolution is hampered by albitization rims shielding K-feldspar and efficiently preventing an equilibration of the Na–K exchange with the fluid. The experiments show changes on the rock surface, leading to an increase of the aperture of a single fracture during the early phases of reaction and later to a decrease as the fluid-rock reaction progresses. Alteration of the fracture surface also generates loose fragments and altered minerals. This fine material may efficiently reduce the fracture aperture at narrow points along the fracture.

Ion conducting nano-composite polymer electrolytes: synthesis and ion transport characterization

Synthesis and ion transport characterization of a new K+-ion conducting nano-composite polymer electrolytes (NCPEs): (1−x) [70PEO:30KBr] + x SiO2, where 0 < x < 20 wt%, are reported. The present NCPEs have been cast using a novel hot-press technique in place of the traditional solution cast method. The conventional solid polymer electrolyte (SPE) composition: (70PEO:30KBr), identified as the highest conducting composition at room temperature, has been used as first-phase host matrix and nano-size (~8 nm) particles of SiO2 as second-phase dispersoid. As a consequence of dispersal of SiO2 in SPE host, two orders of conductivity enhancement have been observed in NCPE composition: [95(70PEO:30KBr) + 5SiO2] and this has been referred to as optimum conducting composition (OCC). The polymer-salt/nano-filler SiO2 complexation and thermal properties characterization were done with the help of XRD, FTIR, SEM, DSC and TGA studies. The ion transport behavior in NCPEs have been discussed on the basis of experimental measurements on some basic ionic parameters, viz. conductivity (σ), ionic mobility (μ), mobile ion concentration (n), ionic transference number (tion), etc. The temperature-dependent conductivity studies of NCPE OCC have been done and activation energy (Ea) value was determined using log σ−1/T Arrhenius plot.

Combined influence of fluorine doping and vacuum annealing on the electrical properties of ZnO:Ta films

In this study, our main focus is to investigate the effects of F doping and post deposition annealing (air and vacuum) on the optical and electrical characteristics of tantalum doped zinc oxide films (ZnO:Ta). A cost-effective, automated jet nebulizer spray pyrolysis technique is adopted to deposit the ZnO:Ta:F films. The doping level of Ta is kept constant (1 at.%) and that of F is varied from 5 to 20 at.% in steps of 5 at.%. The electrical resistivity of the as-deposited films decreases for 10 at.% of F concentration. The resistance increases thereafter. The same trend is also observed in annealed films. The reasons for these variations are addressed based on the effective F incorporation into the ZnO lattice and annealing atmosphere with the help of XRD, FESEM, AFM and PL studies. The incorporation of the dopants was confirmed from XPS and EDX analyses and the DFT studies show that the incorporation of the dopants does not affect the stability of the ZnO lattice. Vacuum-annealed films show better electrical properties over the as-deposited and air-annealed counterparts, though their transparency is affected marginally. A minimum resistivity of 0.81×10−3Ωcm and an enhanced quality factor of 2.265×10−4(Ω/sq)−1 are achieved for the vacuum-annealed films having Ta+F doping levels as 1+10 at.%. These results make this sample a desirable candidate for transparent electrode applications.

Effect of niobium doping on the structure and electrochemical performance of LiNi0.5Co0.2Mn0.3O2 cathode materials for lithium ion batteries

Key issues including poor rate capability and limited cycle life span should be addressed for the extended application of LiNi0.5Co0.2Mn0.3O2 cathode. The suppressed Li+/Ni2+ site exchange, enlarged LiO2 inter-slab space and reduced impedance, which could facilitate the structure stability, were achieved by controlled Niobium (Nb) doping and contributed to enhanced performance even at elevated temperature (55°C). The detailed role of the doped Nb was investigated thoroughly and systematically with the help of XRD, SEM, XPS and related electrochemical tests. The full and accurate results demonstrate that the Li(Ni0.5Co0.2Mn0.3)0.99Nb0.01O2 sample with appropriate Nb doping amount possess high capacity retention of 93.77% after 100 cycles at 1.0C and improved rate performance with 125.5mAhg−1 at 5.0C, which are much better than that of the LiNi0.5Co0.2Mn0.3O2. Moreover, at high temperature of 55°C, Nb doping shows more remarkable effect on stabilizing the structure and 88.63% of the initial reversible capacity could be retained, which is ~20% higher than the LiNi0.5Co0.2Mn0.3O2. This study intensively determines that controlled Nb doping could be effectively maintain the structure stability of advanced LiNi0.5Co0.2Mn0.3O2 cathode and promote the development of high energy density lithium ion batteries.

A COMPARATIVE STUDY ON RECOVERY OF CHROMIUM FROM TANNERY WASTEWATER AS NANO MAGNESIUM CHROMITE

In this paper, two different precipitation routes involving NaOH and MgO were investigated to remove chromium from tannery wastewater. It was found that the optimum pH for precipitation of chromium using NaOH or MgO was from 8.0 to 8.5 to give total chromium removal of 99.1 and 99.7%, respectively. The MgO route showed less sludge and shorter settling time (3h) compared with NaOH route. Furthermore, MgO enhanced dewatering of the sludge and the total chromium removal. Consequently, the chromium in the formed sludge was recovered as magnesium chromite (MgCr2O4) by calcination of the sludge in the temperature range of 550-650 ° C for 6 h. The formed magnesium chromite was characterized with the help of XRD, FE-SEM, FT-IR, TEM and thermal analyses (TGA and DSC). XRD analysis revealed the formation of cubic nano crystalline magnesium chromite powder at a temperature of 550-650 ° C for 6 h. TEM images show that the obtained powders exhibited nanospheres with particle a size less than 40 nm. Such formed materials were a good candidate in various applications such as refractory material and catalytic support.

Advanced nanostructured photocatalysts based on reduced graphene oxide-flower-like Bi2WO6 composites for an augmented simulated solar photoactivity activity

A simple hydrothermal process was proposed to prepare the flower-like Bi2WO6 architectures, and the as-synthesized Bi2WO6 photocatalysts were further processed with the prepared graphene oxide (GO) to form novel reduced graphene oxide (RGO)/Bi2WO6 composites. The nano-materials were characterized with the help of XRD, XPS, SEM, FTIR, UV-DRS, PL techniques to investigate their morphological, physical, optical, and photochemical properties. Photocatalytic performances of the pure flower-like Bi2WO6 architectures and RGO/Bi2WO6 composites were compared and evaluated through the degradation of ciprofloxacin hydrochloride (Cipro HCl) wastewater under the simulated visible light. It was found that the RGO/Bi2WO6 composites displayed enhanced visible light-driven photocatalytic activities. It might be that the RGO loading not only effectively suppressed the electron–hole recombination, but also increased the light absorption ability. The effects of operating condition involved in the photocatalytic process were further examined, and the cycle-stability experiment demonstrated that as-obtained 2% RGO/Bi2WO6 photocatalysts had good photocatalytic repeatability.

An experimental analysis on the influence of fuel borne additives on the single cylinder diesel engine powered by Cymbopogon flexuosus biofuel

Researchers all around the world are making strenuous efforts to find alternative fuel to ameliorate the problem of depletion of fossil fuel. we have identified a novel plant based biofuel, namely Cymbopogon flexuous biofuel. It has excellent fuel properties and is widely available in India and it seems to have the potential to make India self-sufficient in energy production. Cerium oxide nanoparticles were synthesized using sol–gel combustion methods. Their structural, morphological and elemental properties were studied with the help of XRD, SEM, TEM and EDS respectively. On volume basis, 20% raw Cymbopogon flexuous biofuel was blended with diesel fuel, and various proportions of Cerium oxide nanoparticles, namely C20-D80 + 10 ppm, C20-D80 + 20 ppm andC20-D80 + 30 ppm were prepared. The properties like density, kinematic viscosity, calorific value of the test fuel were measured as per ASTM standards and compared with those of diesel fuel. An experimental study of its performance, emission, and combustion behavior was conducted at varied load conditions at a constant speed of 1500 rpm. NOx and smoke emission was simultaneously reduced by 3% and 6.6% respectively as compared with biofuel blend. Due to higher thermal stability and oxygen buffer of Cerium oxide nanoparticle the brake thermal efficiency was higher by 4.76% and cylinder pressure and heat release rate was also higher.

A simple approach for sonochemical synthesis of Cu2O nanoparticles with high catalytic properties

A one step, additive free protocol for ultrasound assisted synthesis of cuprous oxide (Cu2O) nanoparticles using glycerol as a green and sustainable solvent has been developed. The glycerol plays multiple roles in nanoparticle synthesis such as solvent, promoter, reducing agent and capping agent. It assists to control the crystal morphology of obtained Cu2O nanoparticles. The Cu2O nanoparticles were characterized with the help of XRD, TEM, HRTEM, EDS, FT-IR, XPS, BET surface area and TGA techniques. This is simple, green, inexpensive and capping agent free method for the synthesis of Cu2O nanoparticles. Furthermore, we showed catalytic applications of prepared Cu2O nanoparticles in catalysis for the coupling reaction between aryl halide and aromatic amine.

A novel dimethyl sulfoxide/1,3-dioxolane based electrolyte for lithium/carbon fluorides batteries with a high discharge voltage plateau

A novel dimethyl sulfoxide/1,3-dioxolane (DMSO/1,3-DO) based electrolyte is proposed for lithium/carbon fluorides (Li/CFx) batteries to enhance the discharge voltage plateau and energy density. Conductivities of the electrolyte of 1molL−1 LiBF4/DMSO+1,3-DO with different volume ratios are not identical, which have a maximum of 14.85mScm−1. From the tests of galvanostatic discharge, the discharge voltage plateau of the Li/CFx battery with an electrolyte of 1molL−1 LiBF4/DMSO+1,3-DO (5:5, v:v) can reach 2.69V at 0.1C, delivering a maximum discharge capacity of 831mAhg−1 and the highest energy density of 2196Whkg−1. Compared to Li/CFx batteries with an electrolyte of 1molL−1 LiBF4/PC+DME (5:5, v:v), the energy density of Li/CFx batteries with an electrolyte of 1molL−1 LiBF4/DMSO+1,3-DO (5:5, v:v) has been improved more than 12%. With the help of XRD, SEM, TEM, EIS, FT-IR and GC-MS analysis, the results of this work suggest that DMSO/1,3-DO based electrolyte can significantly improve the discharge performance of Li/CFx batteries and keep a good electrochemical stability during discharge. The main reason for improvement of discharge performance is decreasing of both the overpotential of electrochemical polarization of CFx cathodes during discharge and the overpotential of ohmic polarization by increasing the ion conductivity of electrolyte.

Study of Co-Mn/TiO&lt;sub&gt;2&lt;/sub&gt; SCR Catalyst at Low Temperature

The Co-Mn/TiO2 catalysts with different contents of Co were prepared by the impregnation method. Catalytic activity tests showed that the addition of Co could obviously enhance the SCR performance of Mn/TiO2 catalyst, and the NO conversion of 0.05Co-Mn/TiO2 samples could reach 94.03% at 180 °C. At the same time, with the help of XRD, BET, H2-TPR and NH3-TPD, the various physical and chemical characteristics as well as phase structures of catalysts were characterized systematically. According to the results, the formations of crystalline CoMn2O4, Mn3O4 and amorphous Mn2O3 were detected. Furthermore, Co doping could reduce the reduction temperatures of catalysts and enhance the adsorption capacities of NH3, resulting in the excellent SCR performance at low temperature.

Synthesis and characterization of hot pressed ion conducting solid polymer electrolytes: (1 – x) PEO: x NaClO4

Synthesis and ion transport characterization of hot-pressed poly(ethylene oxide) PEO-based solid polymer electrolytes (SPEs): (1 – x ) PEO: x NaClO 4 , where 0 x 4 ) with ionic conductivity ( σ ) ~ 7.07 × 10 −7 S cm −1 shows the highest conducting composition and this have been referred to as optimum conducting composition (OCC). Materials characterization and thermal behavior of the present SPEs have been done with the help of XRD, FTIR, SEM, DSC and TG analysis. To determine the activation energy, temperature dependent ionic conductivity ( σ ) of different compositions has been measured. Ionic nature of the SPEs has been explained with the help of ionic transference number ( t ion ) measurements. Finally, the thin film polymer battery is also fabricated using the SPE OCC as electrolyte and calculated their cell parameters at room temperature.

Effect of A-site substitution in perovskites: Catalytic properties of PrMnO3 and Ba/K/Ce substituted PrMnO3 for CO and PM oxidation

ABO3 type perovskite based catalysts with PrMnO3 composition and its A site substituted variants Pr0.8A0.2MnO3+δ/−δ (A=Ba or K or Ce) have been synthesized by sol–gel method. A systematic study has been carried out to understand the change in physicochemical properties, catalytic properties and related mechanistic aspects of the A site substituted ABO3 type perovskite materials with the help of XRD, BET-SA, SEM, XPS and H2-TPR techniques. These studies have inferred the altered oxidation states of B site cation Mn, as well as change in overall redox properties of PrMnO3, as a function of A site substitution. On the other hand, to study the impact on catalytic properties, these catalysts have been evaluated for two different reactions namely, CO and PM oxidation. The substitution/promotion of alkali metal (K) at A site of the PrMnO3 decreases its catalytic activity towards CO oxidation. However, Ba and Ce substitution in PrMnO3 enhanced the CO oxidation activity. The catalytic activity for PM oxidation was prominently enhanced with the substitution of K at the A site of PrMnO3 as well as with that of Ba and Ce substitutions. XRD, BET-SA, XPS and TPR data enabled to correlate the material properties with the catalytic activity, pointing out the role of substitution element with different valence state. The structure–property correlation for these two different reactions therefore, brings out certain findings about the role of substituted cation in PrMnO3 perovskite type catalysts.