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Rare earth-based perovskite nanostructures are potential materials for electrocatalytic water splitting and energy storage applications due to their great chemical stability. DyMnO 3 nanoaggregates and DyFeO 3 nanoflakes were synthesized using the polymeric citrate precursor and ethylene glycol-assisted hydrothermal routes, respectively. A comprehensive set of characterization techniques, including X-ray diffraction, scanning and transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Brunauer–Emmett–Teller (BET) surface area analysis were carried out. Surface area studies showed that DyMnO 3 has higher specific surface area (33 m2/g) than DyFeO 3 nanoflakes (8 m2/g). Electrochemical water splitting and supercapacitor performance revealed DyMnO 3 nanoaggregates displayed remarkable activity for oxygen evolution reaction with an overpotential of 0.22 V vs. RHE and a faster reaction kinetics. DyFeO 3 nanoflakes demonstrated superior pseudo-capacitance behavior, exhibiting a specific capacitance of 97.82 F/g and 100 % coulombic efficiency. These findings contribute to the advancement of materials design for electrochemical energy conversion and storage applications, emphasizing the potential of rare earth-based perovskite nanostructures in sustainable energy technologies. [Display omitted] • Citrate and hydrothermal techniques employed for diverse synthesis approaches. • Studied multiferroic nature; DyMnO 3 NAs exhibits enhanced characteristics-unit e g filling, high specific surface area. • DyMnO 3 NAs showed superior OER performance (0.22 V vs. RHE) in overall electrocatalytic water splitting. • DyFeO 3 NWs showed superior supercapacitor performance of specific capacitance of 97.82 F/g. [ABSTRACT FROM AUTHOR]

Multiferroic TbCrO 3 nanoparticles were synthesized using solvothermal approach for photocatalytic and electrocatalytic hydrogen generation. As-synthesized TbCrO 3 nanoparticles depicted high surface area of 131 m2/g and room temperature non-ideal ferroelectricity. Sophisticated techniques such as X-ray photoelectron spectroscopy establish chemical purity of TbCrO 3 nanoparticles. TbCrO 3 NPs showed high photocatalytic H 2 evolution of 10 mmol h−1 g−1 which was due to high specific surface area, and ferroelectric charge separation phenomena. In electrocatalytic seawater splitting where OER is replaced by hydrazine oxidation, TbCrO 3 nanoparticles showed improved overpotential (η 10) in HzOR∼0.20 V than OER∼0.22 V vs. RHE. Furthermore, hydrogen evolution reaction and in simulated water was analyzed that showed generation of significant catalytic current density. The as-synthesized multiferroic TbCrO 3 nanoparticles showed multifunctional applications in both photocatalytic and electrocatalytic activity. The high electrocatalytic and photocatalytic activity is attributed to inherent ferroelectric behavior of TbCrO 3 nanoparticles as confirmed by ferroelectric studies. [Display omitted] • Pure TbCrO 3 NPs formed via solvothermal method. • Multiferroic properties are confirmed which enhances catalytic activity. • High photocatalytic H 2 evolution of 10 mmol h−1 g−1. • Improved overpotential (η 10) in HzOR. • Enhanced HER activity in simulated seawater and improved reaction kinetics. [ABSTRACT FROM AUTHOR]

Abstract: Samples of a magnetorheological composite comprised of a silicone elastomer containing varying mixtures of 40- and 10-μm iron particles were tested in dynamic shearing experiments. These bimodal mixtures were used in order to determine whether such particle combinations might influence the composite''s behavior as evidenced by changes in the relative magnetorheological (MR) effect, ΔG. Field-dependent results are consistent with ΔG ∝ M 2, M being the magnetization, and allow one to extrapolate a maximum relative MR effect. The extrapolated maximal ΔG values were effectively independent of particle-size ratio for fixed 30% [v/v%] Fe, suggesting that volume fraction was the important parameter and that particle positions were disordered. However, for 1% [v/v%] of the 10-μm particles to 30% [v/v%] 40-μm particles, there was enhanced response, perhaps due to the smaller particles sitting in beneficial interstitial positions. Further addition of 10-μm particles resulted in decreased performance. [Copyright &y& Elsevier]

Abstract: Nanoparticles of Co-doped CdO with 4.2, 9.3, and 15.4 weight% were successfully synthesized by a modified solvothermal method through oxalate precursor route. The oxalate served as an excellent precursor for the synthesis of pure and homogeneous oxide nanoparticles. Powder X-ray diffraction studies revealed the monophasic nature of these nanoparticles. The lattice parameter decreased monotonically with increasing Co concentration, confirming Co was doped into the CdO host lattice. Particle size decreased and surface area increased on increasing the dopant ion concentration. Optical absorption measurements showed an energy band gap that increased with Co concentration. Magnetization studies indicated that the samples showed paramagnetic behavior with weak antiferromagnetic interactions. [Copyright &y& Elsevier]

• Orthorhombic Bi 2 Fe 4 O 9 exhibited highest OER activity amongst three Bi-Fe-O. • Lowest charge transfer resistance; highest double-layer capacitance for Bi 2 Fe 4 O 9. • Performance of Bi 2 Fe 4 O 9 attributed to Fe oct -O-Fe td linkages, plate-like morphology. • OER activity increased by factor of 4 after electrical polarization for Bi 25 FeO 40. This work aims to give an insight into the influence of crystal structure (for a system containing same elements but crystallizing in different structures) and the effect of electrical polarization on these oxides on the performance of oxygen evolution reaction (OER). We have tried to highlight this influence by taking the Bi-Fe-O system for the study. Herein, we have synthesized three structures of the Bi-Fe-O system viz. BiFeO 3 (perovskite structure), Bi 2 Fe 4 O 9 (mullite structure), and Bi 25 FeO 40 (sillenite structure) as an example to establish the relation. These oxides were characterized by Rietveld refinement for structure and scanning electron microscopy (SEM) for morphology. Their optical and magnetic properties were also investigated. Systematic studies were carried out with both as-synthesized and electrically polarized oxides for their performance towards OER. We observed that the order for OER activity (using non-polarized catalyst) of the three stable structures synthesized was Bi 2 Fe 4 O 9 > BiFeO 3 > Bi 25 FeO 40 , which was attributed to the presence of Fe (oct) -O-Fe (td) linkages in Bi 2 Fe 4 O 9. While the current density of Bi 2 Fe 4 O 9 and BiFeO 3 remained unchanged after poling, that of Bi 25 FeO 40 increased by four-fold. From the study, we have demonstrated that proper choice of the crystal structure and utilization of electrical polarization can be effective strategies to manipulate the surfaces of an electrocatalytic material. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Traditionally, the synthesis of CoFe nanoparticles with tunable particle sizes and narrow particle size-distributions is accomplished via the use of expensive and air sensitive precursors and strong non-polar capping agents. Such strong capping agents can be difficult to remove from the nanoparticles and thus render them catalytically inactive. We report a novel solution-based methodology to synthesize CoFe alloy nanoparticles with narrow size-distributions using a combination of robust and inexpensive metal precursors and an easily removable polar capping agent. High resolution transmission electron microscope images show that the CoFe alloy nanoparticles are well crystallized, and the particle size is tunable from 9 to 24 nm while keeping a particle size standard deviation of 10%. The CoFe alloy nanoparticles show superior activity for NaBH4 hydrolysis compared with the best-known CoFe catalysts. This work represents a substantial improvement in the synthesis of transition metal nanoparticles, opening the pathway for their application to a number of technologically important catalytic applications. [Copyright &y& Elsevier]

Abstract: Mn-doped indium oxide (In2− x Mn x O3) nanoparticles (7–12nm) with x =0.05, 0.10 and 0.15 have been synthesized by solvothermal method using oxalate precursor route for the first time. Powder X-ray diffraction studies showed the formation of monophasic cubic structure of In2− x Mn x O3 solid solutions. X-ray diffraction and UV–visible reflectance studies revealed that Mn2+ ions are doped into the In2O3 lattice. Reflectance measurements showed red shift in an energy band gap which decreases with an increase in the Mn concentration. Maximum surface area of 768m2 g−1 is obtained for In1.85Mn0.15O3 nanoparticles. Magnetization measurement revealed that all the samples are paramagnetic in nature with very weak antiferromagnetic interactions. [Copyright &y& Elsevier]

Abstract: Cu–Ni (1:3, 1:1, 3:1) bimetallic nanoparticles have been synthesized by a microemulsion route using CTAB (cetyltrimethyl ammoniumbromide) as the surfactant and hydrazine/NaOH as the precipitating agent followed by reduction in hydrogen atmosphere. This is the first report of the synthesis of CuNi3 and Cu3Ni nanoparticles. Transmission electron microscopy (TEM) studies show nearly monodisperse and uniform nanoparticles of average grain size of 7nm for the 1:1 alloy nanoparticles while the 1:3 and 3:1 compositions show uniform nanoparticles with the grain size in the range of 20–30nm. X-ray photoelectron spectroscopy (XPS) studies confirm the expected Cu/Ni ratios in these alloys. These bimetallic nanoparticles show ferromagnetic behavior and the magnetization decreases with increase in concentration of copper. The specific surface area of these alloy nanoparticles was found to be in the range of 6–9.42m2/g. [Copyright &y& Elsevier]

Abstract: Homogeneous nanoparticles of nickel oxide (NiO) of 25 nm size with narrow size distribution have been synthesized by the reverse-micellar route using CTAB (cetyltrimethyl ammonium bromide) as the surfactant. FTIR studies show a broad absorption around 405–415 cm−1 and a weak absorption around 82 cm−1 corresponding to a surface-active mode, which is indicative of the nanocrystalline nature of the oxide. Magnetization studies show nearly temperature independent paramagnetism with high magnetic moment compared to bulk NiO. Cyclic voltammetric (CV) studies show well-resolved anodic peak () at 0.45 V at a scan rate of 1 mV/s, which shifts to 0.47 V at the scan rate of 100 mV/s. The cathodic peak () is also observed at 0.34 V, which remains at the same position irrespective of the sweep rate. The quasireversible nature of the voltammograms suggests the usefulness of these materials for ultracapacitor applications. [Copyright &y& Elsevier]

Abstract: Nanoparticles of Cd1− x Mn x O (0.04< x =0.10) have been prepared using solvothermal method through oxalate precursor route for the first time. Thermal decomposition of the oxalate precursors were studied by thermogravimetric analysis in nitrogen atmosphere and their kinetics has also been studied. Kinetic analysis according to Freeman and Carroll method showed that activation energy increases on increasing the Mn concentration. X-ray diffraction studies showed the formation of cubic structure of all the oxides with no additional peaks corresponding to secondary phase. Optical absorption measurements showed an energy band gap which increased with Mn doping. This simple and inexpensive method was found to be effective in the preparation of Mn-doped CdO nanoparticles in the range of 18–25nm. Particle size decreased from 25 to 18nm and likely the surface area increases from 56 to 107m2 g−1 on increasing the Mn concentration from 4wt.% to 10wt.%. Magnetic measurements revealed the paramagnetic behavior with no sign of long-range order above 5K. [Copyright &y& Elsevier]

Abstract: Single crystals of the quaternary thiospinel Ag1.41(1)Cr1.47(5)Sn2.52(5)S8 have been obtained by heating stoichiometric mixtures of elemental metals and sulfur at 750°C. Structural analysis by single crystal X-ray diffraction shows that the above phase crystallizes in the space group with a=10.4142(3)Å (R1=0.0156 and wR2=0.0416). The Ag-deficiency has been confirmed by solving the structures of crystals prepared in different batches and was observed to vary slightly between crystals. Magnetic studies on a monophasic powder sample with a nominal composition of Ag1.63CrSn3S8 indicates anti-ferromagnetic ordering at low temperature. The high temperature susceptibility leads to a magnetic moment of 3.45B.M. suggesting that chromium exists predominantly in a trivalent state. [Copyright &y& Elsevier]