All inorganic based Nd0.9Mn0.1FeO3 perovskite for Li-ion battery application: Synthesis, structural and morphological investigation

Mn doped perovskite structured Nd0.9Mn0.1FeO3 nanoparticles have been successfully prepared using hydrothermal method in aqueous medium. The structural and morphological properties were investigated using XRD, SEM, FE-SEM, and TGA. After establishing the structure and morphology of the compound, thorough investigation into elemental composition with the use of EDX and XPS were carried out. Microstructure arrangement was done with the use of HR-TEM while the BET analysis confirmed the high surface area of the nanoparticles. The structural information was further investigated by AFM. The average particle size of Nd0.9Mn0.1FeO3 nanoparticles increased from 60 to 100 nm with increasing annealing temperature from 500 to 1000 �C, respectively. The structural characterizations confirmed the perovskite nanoparticles to be crystalline orthorhombic structure. Moreover, the new material was explored as anode material for Li-ion battery. The galvanostatic cycling measurement shows that the cells possess reversible specific capacity of 763 mAhg�1 at a current density of 0.5 A g�1 after 100 cycles. The charging and discharging profiles shows that the compound of this kind could be future candidate for electrode material

Hydrothermal assisted morphology designed MoS2 material as alternative cathode catalyst for PEM electrolyser application

In this work, we developed a simple and cost-effective hydrothermal route to regulate the formation of molybdenum disulfide (MoS2) in different morphologies, like, nano-sheet, nano-capsule and nano-flake structure by controlling the reaction temperature and sulphur precursor employed. Such a fine tuning of different morphologies yields a leverage to obtain novel shapes with high surface area to employ them as suitable candidates for hydrogen evolution catalysts. Moreover, we report here the first time observation of MoS2 nano-capsule formation via environmentally benign hydrothermal route and characterized them by X-ray diffraction (XRD), nitrogen adsorption and desorption by Brunaer–Emmett–Teller (BET) method, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and X-ray photo-electron spectroscopy (XPS) techniques. MoS2 nano-capsules exhibits superior activity towards hydrogen evolution reaction (HER) with a low over-potential of 120 mV (RHE), accompanied by large exchange current density and excellent stability in 0.5 M H2SO4 solution. MoS2 nano-capsule catalyst was coated on solid proton conducting membrane (Nafion) and IrO2 as anode catalyst. The performance of the catalyst was evaluated in MEA mode for 200 h at 2 V without any degradation of electrocatalytic activity

Integration of phenylammoniumiodide (PAI) as a surface coating molecule towards ambient stable MAPbI3 perovskite for solar cell application

In the present work, different hybrid perovskites were synthesized by gradual concentration variation of larger cation of phenylammoniumiodide (PAI) and methylammoniumiodide (MAI) in PbI2 solution with the aim of improving the stability of MAPbI3 film and photovoltaic efficiency. To understand the properties of perovskite like structural, optical, thermal, morphological and chemical state, extensive characterizations such as XRD, UV–visible spectroscopy, FE-SEM, SEM, EDX and XPS were performed. The role of PAI was investigated further with the use of DFT studies. The DFT results confirmed that the PAI was passivated on the surface of MAPbI3 with most stable arrangement. The stable arrangement revealed the formation of ᴫ-ᴫ interactions within the phenyl rings, which shielded the MAI crystals and thereby resulted in enhanced stability of the perovskites. Highly protected perovskite consequently yielded high- performance solar cell device with enhanced stability under 60% humidity, high temperature exposure and longer time stability even when directly exposed to normal room temperature. The new investigation of capping techniques with the use of bigger organic molecules, high performance solar cell with low device costs could emerge. This could lead to unprecedented rapid progress on power conversion efficiency (PCE). Thus, more stable organic-inorganic hybrid perovskites could be developed for future applications

Single-atom Cu anchored catalysts for photocatalytic renewable H2 production with a quantum efficiency of 56

Single-atom catalysts anchoring offers a desirable pathway for efficiency maximization and cost-saving for photocatalytic hydrogen evolution. However, the single-atoms loading amount is always within 0.5% in most of the reported due to the agglomeration at higher loading concentrations. In this work, the highly dispersed and large loading amount (>1 wt%) of copper single-atoms were achieved on TiO2, exhibiting the H2 evolution rate of 101.7 mmol g-1 h-1 under simulated solar light irradiation, which is higher than other photocatalysts reported, in addition to the excellent stability as proved after storing 380 days. More importantly, it exhibits an apparent quantum efficiency of 56% at 365 nm, a significant breakthrough in this field. The highly dispersed and large amount of Cu single-atoms incorporation on TiO2 enables the efficient electron transfer via Cu2+-Cu+ process. The present approach paves the way to design advanced materials for remarkable photocatalytic activity and durability

Growth of well graphitized MWCNTs over novel 3D cubic bimetallic KIT-6 towards the development of an efficient counter electrode for dye-sensitized solar cells

The well graphitized multi-walled carbon nanotubes (MWCNTs) have been effectively synthesized over ordered 3D cubic bimetallic Fe–Co-KIT-6. The synthesized MWCNTs have been successfully fabricated onto transparent conducting oxide glass and implemented as efficient low-cost, platinum-free counter electrode in dye-sensitized solar cells (DSSCs), attributing notably improved electrocatalytic activity towards iodide/tri-iodide ðI�=I� 3 Þ redox transport over conventional Pt counter electrode. Impressively, device with MWCNTs counter electrode demonstrates a high fill factor of 0.79 and power conversion efficiency up to 9.56%, which is higher than 0.78 and 9.34% for that with a conventional Pt counter electrode. Moreover, the synthesized MWCNTs counter electrode produces a charge transfer resistance of only 2.99 X cm2 towards aqueous I�=I� 3 redox electrolyte, which are several orders of magnitude lower than that of a typical Pt counter electrode (3.57 X cm2). Therefore, the synthesized MWCNTs counter electrode is believed to be a versatile candidate for further improvement of the power conversion efficiency of iodine redox couple based DSSC

Effective synthesis of carbon nanotubes of high purity over Cr–Ni–SBA-15 and its application in high performance dye-sensitized solar cells

The synthesis of carbon nanotubes (CNTs) by chemical vapour deposition (CVD) using 2D hexagonal ordered mesoporous SBA-15 supported mono and bimetallic catalysts using chromium (Cr) and nickel (Ni) were prepared by a post-synthesis grafting process. The structure of the synthesized well graphitized CNTs with a uniform diameter was investigated by transmission electron microscopy, X-ray diffraction, thermogravimetry and Raman spectroscopy. Studies performed to evaluate the quality and quantity of the synthesized CNTs provide evidence in support of the superior catalytic nature of the bimetallic (Cr–Ni) catalyst over the mono metallic (Cr/Ni) catalysts. The CNTs synthesized using Cr–Ni–SBA-15 catalysts were coated on fluorine doped tin oxide conductive glass by spin-coating and evaluated as a counter electrode for dye-sensitized solar cells (DSSCs). It was observed that the counter electrode based on CNTs exhibited a photo conversion efficiency of 9.34%, which was slightly higher than that observed with a conventional Pt counter electrode (9.09%). The lower charge transfer resistance and higher electrocatalytic activity of the CNT counter electrode over the Pt counter electrode was confirmed by electrochemical impedance spectroscopy and cyclic voltammetry, respectively. The studies showed that the CNTs synthesized over Cr– Ni–SBA-15 could be employed as a counter electrode in DSSCs as a replacement for P

Growth of carbon nanotubes over transition metal loaded on Co-SBA-15 and its application for high performance dye-sensitized solar cells

High quality MWCNT material based counter electrodes for dye-sensitized solar cells (DSSCs) were fabricated using a novel route and their power-conversion efficiency was studied. Transition metals such as Fe, Ni, V, Mn, Cr, Mo, Ru and Pd loaded on Co-SBA-15 molecular sieves were synthesized and tested for the formation of MWCNTs at different temperatures (700–1000 �C) using a chemical vapour deposition (CVD) method. This result showed that Fe/Co-SBA-15 and Ru/Co-SBA-15 systems are highly suitable sources as catalysts for the growth of MWCNTs compared to other bimetallic systems. TEM and Raman spectroscopy revealed that the synthesized MWCNTs were of high quality and well-graphitized. The MWCNTs were applied to the counter electrode of dye-sensitized solar cells (DSSCs). Cyclic voltammetry measurements proved that the catalytic activity of the MWCNT coated electrode towards I3 � reduction was significantly higher than that of the Pt coated electrode. Electrochemical impedance measurement of the symmetric cell revealed that the charge transfer resistance of the MWCNT coated electrode was less than that of the Pt coated electrode. Due to the low charge transfer resistance of the synthesized MWCNTs, the DSSCs with MWCNTs as counter electrode gave better photoelectric performance compared to DSSCs equipped with a conventional Pt counter electrod

Effective Synthesis of Well-Graphitized Carbon Nanotubes on Bimetallic SBA-15 Template for Use as Counter Electrode in Dye-Sensitized Solar Cells

The fabrication of dye-sensitized solar cells (DSSCs) using well-graphitized carbon nanotubes (CNTs) as a counter electrode has been described in this study. The well-graphitized CNTs were synthesized at different temperatures (700, 800, and 900 °C) using bimetallic Fe-V catalyst supported on Santa Barbara Amorphous-15 (SBA-15). The molecular ratios between the two metals were varied in the catalytic template, and their effect on the distribution of the synthesized CNTs was studied. Cyclic voltammetry and electrochemical impedance spectroscopy revealed that the CNTs had higher electrochemical activity for the I3 −/I− redox reaction and a smaller charge transfer resistance than the platinum (Pt) electrode. Energy conversion efficiency of the CNTs was compared with Pt counter electrode. These results indicated that the CNTs have high surface conductivity, high active surface area, and good catalytic activity and can potentially replace Pt as counter electrode for application in DSSC

Facile fabrication of dye-sensitized solar cells utilizing carbon nanotubes grown over 2D hexagonal bimetallic ordered mesoporous materials

High-surface area and well-ordered mesoporous Fe incorporated SBA-15 (Fe-SBA-15), FeeCr incorporated SBA-15 (FeeCr-SBA-15) and Cr incorporated SBA-15 (Cr-SBA-15) catalysts are synthesized following a controlled post synthesis grafting process. The activities of all the catalysts are tested systematically and quantitatively towards the production of carbon nanotubes (CNTs) by chemical vapour deposition. In order to obtain CNTs with high quality and quantity, the parameters like temperature, reaction time and gas flow rate are optimized. Under optimum conditions, the FeeCr-SBA- 15 catalyst is produced with high yield and uniform diameter of CNTs. The transmission electron microscopy result reveals high purity and well-graphitized structure of CNTs. The synthesized CNTs are used as counter electrode material for dye-sensitized solar cells (DSSCs). The CNTs based counter electrode shows good chemical stability, lower charge-transfer resistance and higher electrocatalytic activity towards I3 �/I� redox reaction than that of platinum (Pt) counter electrode. The energy conversion efficiency of the CNTs counter electrode based DSSCs reaches 8.86% under irradiation with a simulated solar light intensity of 100mWcm�2. The results prove that CNTs are one of the suitable candidates for Pt free counter electrode for DSSC

Facile and controlled growth of SWCNT on well-dispersed Ni-SBA-15 for an efficient electro-catalytic oxidation of ascorbic acid, dopamine and uric acid

High-surface area and well-ordered mesoporous Ni incorporated SBA-15 (Ni-SBA-15) catalysts were synthesized following a controlled post synthesis grafting process. The activities of these catalysts were evaluated in the synthesis of uniform diameter single walled carbon nanotubes (SWCNTs) adopting high temperature methane pyrolysis under atmospheric pressure. The characteristics of SWCNTs were confirmed by X-ray diffraction, thermogravimetric analysis, transmission electron microscopy (TEM) and Raman spectroscopy. The TEM micrographs reveal that the SWCNTs were mostly entangled bundles with diameters of about 2–3 nm. Raman spectra prove that the SWCNTs synthesized at 900 ◦C posses low amount of amorphous/defected carbon with very low ID/IG ratio. The radial breathing mode Raman peaks confirm the formation of SWCNTs of <3 nm diameter. SWCNTs modified glassy carbon electrode (GCE) has been developed and tested in 0.1 M phosphate buffer solution of pH 4.5. The SWCNTs/GCE exhibits superior electro-catalytic activity toward ascorbic acid (AA), dopamine (DA) and uric acid (UA). Moreover, AA, DA, UA were oxidized separately at distinguishable potentials along with well defined peaks thereby making possible for simultaneous determination of each compound