Emerging Trends in Nanomedicine: Carbon-Based Nanomaterials for Healthcare.

Carbon-based nanomaterials, such as carbon quantum dots (CQDs) and carbon 2D nanosheets (graphene, graphene oxide, and graphdiyne), have shown remarkable potential in various biological applications. CQDs offer tunable photoluminescence and excellent biocompatibility, making them suitable for bioimaging, drug delivery, biosensing, and photodynamic therapy. Additionally, CQDs' unique properties enable bioimaging-guided therapy and targeted imaging of biomolecules. On the other hand, carbon 2D nanosheets exhibit exceptional physicochemical attributes, with graphene excelling in biosensing and bioimaging, also in drug delivery and antimicrobial applications, and graphdiyne in tissue engineering. Their properties, such as tunable porosity and high surface area, contribute to controlled drug release and enhanced tissue regeneration. However, challenges, including long-term biocompatibility and large-scale synthesis, necessitate further research. Potential future directions encompass theranostics, immunomodulation, neural interfaces, bioelectronic medicine, and expanding bioimaging capabilities. In summary, both CQDs and carbon 2D nanosheets hold promise to revolutionize biomedical sciences, offering innovative solutions and improved therapies in diverse biological contexts. Addressing current challenges will unlock their full potential and can shape the future of medicine and biotechnology.

Ambient pressure synthesis and structure and magnetic properties of a new A- and B-site ordered multinary quadruple perovskite.

Quadruple perovskites with high magnetic transition temperatures are an interesting class of compounds but are synthesized typically under high pressure. Ambient pressure synthesis of new multinary quadruple perovskites having a high global instability index (GII) and transition temperature can be interesting for future exploration of high-TC oxides. A new A- and B-site ordered multinary quadruple perovskite, LaCu3Fe2RuSbO12, is synthesized by conventional solid-state reactions at ambient pressure. Rietveld structure refinement revealed that the compound crystallizes in the Pn3̄ space group with a lattice parameter of 7.4556(4) Å. The compound showed complete 1 : 3 ordering of La and Cu at the A-site and 1 : 1 rock-salt ordering of Fe with Ru/Sb at the B-site. The compound is also probed with scanning and transmission electron microscopy and XPS to investigate the chemical composition, microstructure, lattice and oxidation states of the elements. Magnetic studies revealed antiferromagnetic (AFM) correlations with magnetic ordering transitions at ∼170 and 40 K. Furthermore, the M-H hysteretic behavior at 100 and 5 K indicated ferrimagnetism due to short-range AFM interactions among Fe3+(3d5) and Ru4+(4d4) spins involving Cu2+(↑)-Fe3+(↓)-Ru4+(↑) triads. The specific heat data reaffirmed the magnetic signatures while electrical transport showed semiconducting behavior with variable range hopping. The details of synthesis and structural and compositional studies along with the magnetic and electrical transport properties of LaCu3Fe2RuSbO12 are reported in this paper.

Simple to Quadruple Perovskite Transformation by Coordination Switching upon Solid-State Ion Exchange of NaNbO3.

Topotactic ion exchange is ubiquitous in the preparation of many metastable solids with layered structures. In recent times, the scope of chimie-douce ion exchange has been extended to quasi-2D and -3D structures including nanocrystals. The low-temperature solid-state exchange is yet another unique synthetic tool to access preconceived structures for the rational design of solids. Although rational synthesis using inorganic synthons is rare, few examples exist among inorganic solids with layered structures. Herein, we extend the scope further by transforming a simple perovskite (ABO3) into a high-pressure quadruple (AA'3B4O12) perovskite. The transformation is achieved at moderate temperatures and ambient pressure via a solid-state metathesis reaction, wherein the transition metal adopts a new A-cation coordination upon exchange. Such coordination switching upon ion exchange will open up possibilities for functionality-driven structural transformations and the rational design of new solids.

The role of reducibility vis-à-vis oxygen vacancies of doped Co3O4/CeO2 in the oxygen evolution reaction.

Electrochemical water splitting, which is a highly promising and environmentally friendly technology for H2 fuel production, faces significant hurdles due to the sluggish kinetics of the oxygen evolution reaction. Co -based oxides have garnered significant attention as alternative catalysts for the oxygen evolution reaction owing to the Co2+/Co3+ redox couple. Enhancing the challenging Co2+ → Co3+ oxidation process can further improve the catalytic oxygen evolution reaction. The aim of our work was to design a Co3O4-based catalyst to enhance reactivity by increasing the number of Co3+ active sites, serving as an excellent platform for facilitating the oxygen evolution reaction. To drive the effectiveness of the catalyst, in this study, we synthesized Co3O4 anchored on CeO2 (Co3O4/CeO2). The kinetics and efficacy of the oxygen evolution reaction catalysed by Co3O4/CeO2 was significantly improved by aliovalent doping of Sr into Ce sites and Cu into Co sites. The reducible nature of Ce stimulates the formation of Co3+ ions, resulting in an increased production of intermediate -OOH species, thus expediting the reaction. The transformation of Co2+ to Co3+ consequently leads to an increase in anion vacancies, which, in turn, promotes the adsorption of more intermediate species at the active site. The Sr- and Cu-doped Co3O4/CeO2 catalyst exhibited a high current density of 200 mA cm-2 at 580 mV and a low overpotential of 297 mV at 10 mA cm-2. The study functions as a key indicator to establish a connection between oxygen vacancies and metal oxidation states in order to investigate the mechanistic aspects of the oxygen evolution reaction on mixed metal oxides. Moreover, this study is expected to pave the way for the development of innovative oxygen evolution reaction catalysts with reducible supports, thus offering a new pathway for their design.

Space-dependent intermittent feedback can control birhythmicity.

Birhythmicity is evident in many nonlinear systems, which include physical and biological systems. In some living systems, birhythmicity is necessary for response to the varying environment while unnecessary in some physical systems as it limits their efficiency. Therefore, its control is an important area of research. This paper proposes a space-dependent intermittent control scheme capable of controlling birhythmicity in various dynamical systems. We apply the proposed control scheme in five nonlinear systems from diverse branches of natural science and demonstrate that the scheme is efficient enough to control the birhythmic oscillations in all the systems. We derive the analytical condition for controlling birhythmicity by applying harmonic decomposition and energy balance methods in a birhythmic van der Pol oscillator. Further, the efficacy of the control scheme is investigated through numerical and bifurcation analyses in a wide parameter space. Since the proposed control scheme is general and efficient, it may be employed to control birhythmicity in several dynamical systems.

Specific Instantaneous Detection of Klebsiella pneumoniae for UTI Diagnosis with a Plasmonic Gold Nanoparticle Conjugated Aptasensor.

Urinary tract infection (UTI), which can be caused by various pathogens, if not detected at an early stage can be fatal. It is essential to identify the specific pathogen responsible for UTI for appropriate treatment. This study describes a generic approach to the fabrication of a prototype for the noninvasive detection of a specific pathogen using a tailor-made plasmonic aptamer-gold nanoparticle (AuNP) assay. The assay is advantageous because the adsorbed specific aptamers passivate the nanoparticle surfaces and reduce and/or eliminate false-positive responses to nontarget analytes. Based on the localized surface plasmon resonance (LSPR) phenomena of AuNP, a point-of-care aptasensor was designed that shows specific changes in the absorbance in the visible spectra in the presence of a target pathogen for robust and fast screening of UTI samples. In this study, we demonstrate the specific detection of Klebsiella pneumoniae bacteria with LoD as low as 3.4 × 103 CFU/mL.

Co-electrolysis of seawater and carbon dioxide inside a microfluidic reactor to synthesize speciality organics.

We report co-electrolysis of seawater and carbon dioxide (CO2) gas in a solar cell-integrated membraneless microfluidic reactor for continuous synthesis of organic products. The microfluidic reactor was fabricated using polydimethylsiloxane substrate comprising of a central microchannel with a pair of inlets for injection of CO2 gas and seawater and an outlet for removal of organic products. A pair of copper electrodes were inserted into microchannel to ensure its direct interaction with incoming CO2 gas and seawater as they pass into the microchannel. The coupling of solar cell panels with electrodes generated a high-intensity electrical field across the electrodes at low voltage, which facilitated the co-electrolysis of CO2 and seawater. The paired electrolysis of CO2 gas and seawater produced a range of industrially important organics under influence of solar cell-mediated external electric field. The, as synthesized, organic compounds were collected downstream and identified using characterization techniques. Furthermore, the probable underlying electrochemical reaction mechanisms near the electrodes were proposed for synthesis of organic products. The inclusion of greenhouse CO2 gas as reactant, seawater as electrolyte, and solar energy as an inexpensive electric source for co-electrolysis initiation makes the microreactor a low-cost and sustainable alternative for CO2 sequestration and synthesis of organic compounds.

Architecture of dual emissive three-dimensional nanostructure composites containing graphitic 2D sheets and iron oxide nanoparticles: detection of short single-stranded DNA sequences.

Here, we report an effect driven by repetitive heating and cooling; as a result, 2D and 1D nanomaterials are parallelly produced locally in a single reactor from the same precursors. Afterward, more repetitive heating and cooling induced the self-folding approach of a 2D nanomaterial with a 1D nanomaterial, giving them a self-assembled biconcave disk-shaped 3D nanostructure. The microscopy and spectroscopy studies reveal that the nanostructure has a diameter of nearly 200 nm and is composed of Fe, C, O and incorporated N and P. This 3D nanostructure composite shows red-shifted dual emission (430 nm and 500 nm) at two different excitations (350 nm and 450 nm), accompanied by a rare large Stokes shift (LSS), and it was employed in the detection of targeted short single-stranded DNA sequences (ssDNA). Upon the addition of target DNA, the specific binding of 3D nanostructure probes with the target triggers variations (off/on) of two signals, and by considering the decreased emission (fluorescence quenching) at 500 nm, we can detect the target ssDNA at the single-molecule level. The change of fluorescence intensity and the concentration of complementary target ssDNA sequences show a better linear relationship than a single emission-based probe, and the limit of detection (LOD) was as low as 0.47 nM.

N-Doped Carbon Dots and ZnO Conglomerated Electrodes for Optically Responsive Supercapacitor Applications.

The over-dependence of human society on fossil fuels for energy is exhausting the level of such non-renewable energy sources. Alternative energy storage systems have gained more popularity recently to counter this issue. In this context, we report the fabrication of N-doped carbon dot (N-CD)-decorated ZnO-based electrodes for supercapacitor applications. Due to the light-responsive nature of the N-CDs and ZnO, the electrode was also responsive under the influence of UV light. After the experimental tests, it was found that the areal capacitance value of the supercapacitor increased upto ∼58.9% when illuminated compared to that under the dark conditions. Moreover, the device showed a maximum areal capacitance of 2.6 mF/cm2 after photocharging and galvanostatically discharging at a current density value of 1.6 µA/cm2, which is quite comparable with the previously reported data. The doping of N-CDs with ZnO showed a significant improvement in the areal capacitance value under both illuminated (∼58.64%) and dark conditions (∼22.08%) compared to the case of pristine ZnO, which justifies the purpose of attaching N-CDs with ZnO. Therefore, in brief, we have fabricated a photoresponsive electrode material for supercapacitor application by combining N-CDs and ZnO. An explicit electrochemical characterization of the electrode was also done to identify the contribution from diffusion-controlled capacitance and double layer capacitance, and it was observed that the diffusion-controlled capacitance gets reduced from 59.1 to 33.6% when the scan rate is increased from 2 to 75 mV/s. Moreover, a detailed study has also been done to understand the reaction mechanism. It was confirmed that the defects in the electrode material played a vital role in the intercalation of K+ ions.

Kelvin-Helmholtz Instability Augmented by von Kármán Vortex Shedding during an Oil Droplet Impact on a Water Pool.

The impact of an oil droplet on a water surface has been explored with the aid of computational fluid dynamics simulations. The study reveals the details of the spatiotemporal evolution of such a ternary system with a triplet of interfaces, e.g., air-water, oil-water, and oil-air, when the impact velocity of the oil droplet with the water surface is high. The oil droplet is found to flatten, spread, stretch, and eventually dewet on the water surface of the deep crater to show a host of interesting post-impact flow morphologies. Furthermore, at higher impact velocities, the formation of a biphasic oil-water crown is observed followed by the ejection of secondary water droplets from the crown tip due to capillary instability. The rapidly spreading oil film on the "crater" of the water surface is found to undergo Kelvin-Helmholtz instability before dewetting the same due to cohesion failure. Subsequently, the formation of an array of secondary oil droplets is observed during the process of dewetting. The dominant wavelength evaluated from the linear stability analysis of a representative flow system could faithfully predict the simulated spacing of dewetted oil droplets floating on the crater. Importantly, the variations in Laplace pressure around the curvatures of the undulatory interfaces along with sharp viscosity gradients across the three-phase contact line is found to engender interesting recirculation patterns, which eventually shed to form a coherent wake region in air near the crater. We also uncover the conditions under which the counter-rotating vortices shed along the oil-water interface resembling a von Kármán vortex street.

Construction of Bimetallic Hybrid Multishell Hollow Spheres via Sequential Template Approach for Less Cytotoxic Antimicrobial Effect.

This work has aimed to synthesize less cytotoxic but antibacterial effective materials. Here we synthesized zinc, titanium nanoparticles based multishell hollow spheres (ZnO@TiO2 MSHS) via sequential template approach (STA) and studied their comparative antimicrobial activity with pure zinc and titanium nanoparticles (NPs). Various techniques have been used to explore the physico-chemical properties of the hybrid shells (ZnO@TiO2 MSHS). FTIR, XRD measurements approved the enhanced crystallinity of synthesized hybrid MSHS via STA technique constructed by ZnO, TiO2 NPs. The optical transmittance was enhanced 67.08% for ZnO@TiO2 MSHS where 50.59 %, and 53.32 % of pure ZnO, TiO2 NPs respectively. TEM images showed MSHS made up of zinc and titanium nanoparticles distributed evenly in the structure. The antibacterial activity has been studied and measured via MIZ confirmed that the ZnO@TiO2 multishell hollow spheres exhibit the antibacterial performance. On the other hand the cytotoxicity studies show the cell toxicity was decreased for ZnO@TiO2 MSHS than pure ZnO and TiO2 NPs. So it is recommended that ZnO@TiO2 multishell hollow spheres may be used as a safe and potential antibacterial agent in the field of food packaging, painting, drug delivery and other antibacterial applications.

Targeting Wnt/ß-catenin signaling pathway in triple-negative breast cancer by benzylic organotrisulfides: Contribution of the released hydrogen sulfide towards potent anti-cancer activity.

The potent anti-cancer activity of naturally occurring organopolysulfides has attracted wide research attention over the last two decades. Sustained donation of hydrogen sulfide (H2S) from organopolysulfides is found to be beneficial for the treatment of several organ-specific cancers. In the present study, for the first time, the mechanism of action for the potent anti-cancer activity of bis(3,5-dimethoxybenzyl) trisulfide 4 against highly aggressive triple-negative breast cancer cells (MDA-MB-231) is described. Preliminary in vitro studies revealed potent anti-proliferative activity of the trisulfide 4 against triple-negative breast cancer cells with an IC50 value of 1.0 µM. Mechanistic studies reveal that the compound exhibited anti-cancer activity, primarily by targeting and suppressing the Wnt/ß-catenin signaling pathway. The inactivation of the ß-catenin level was associated with the cell cycle arrest in the G2/M phase and the significant down-regulation of downstream signaling genes such as Cyclin D1 and c-Myc expression. Several control experiments with analogous organosulfur compounds and the key enzyme inhibitors reveal that the presence of a trisulfide unit in the compound is crucial for the desired inactivation of ß-catenin expression, which is promoted by GSK-3ß-induced phosphorylation of ß-catenin and its proteasomal degradation. Moreover, the trisulfide unit or the released H2S induced down-regulation of the p53 expression with the possible S-sulfhydration process led to p53-independent up-regulation of p21 expression. Therefore, the key results of this study highlighting the potency of synthetic benzylic organotrisulfide and the released H2S towards the growth inhibition of triple-negative breast cancer via Wnt/ß-catenin signaling pathway would certainly be helpful for further studies and developing small-molecule anti-cancer therapeutics in future.

Influence of the pre-impact shape of an oil droplet on the post-impact flow dynamics at air-water interface.

We computationally explore the effects of pre-impact shape of an oil droplet on the spatiotemporal dynamics after the droplet impacts an air-water interface. Simulations reveal that the initial shape of the impacting oil-droplet alters the post-impact transient flow structures during the evolution. The spherical and oblate drop spreads over the crater to manifest interesting flow morphologies including the formation of oil-toroids and compound oil-droplets. However, the prolate drop impinges much deeper into the water pool after impact to create a few more exclusive flow features, such as, interface overturning, vortex shedding and formation of secondary droplets. The temporal variation of the crater depth shows distinct three stage dynamics, which can be explained by the generic energy analysis of the entire system. The combined theoretical and numerical energy analyses reveal the influences of the pre-impact drop shape and their effects on the subsequent energy conversion after the impact takes place. The analysis also reveals that the initial surface and kinetic energies are different for non-spherical droplets than for the spherical ones. The conversion of such excess surface energy due to the non-spherical curvature into kinetic energy dictates the impact and subsequently the crater dynamics of such systems. Such influences largely lead to the exclusive flow patterns demonstrated here. Concisely, this study presents a tri-phasic computational model, which is capable of analyzing the salient features of the impact and splash dynamics of the non-spherical droplets into a water continuum.

Effect of Cerium Oxide Nanostructures on CO Oxidation.

Cerium oxide particles with different morphologies, namely nanoparticles, nanofibers, nanocubes, and rice grains have been prepared by simple chemical routes. The shape and size of the synthesized morphologies have been studied using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) and selected area electron diffraction (SAED) techniques have been used to determine their crystal phases. Both nanoparticles and nanocubes of cerium oxide exclusively crystallize in fluorite structure of CeO2 as observed in XRD patterns, whereas nanofibers and rice grains are characterized by the presence of CeO2, Ce2O3, and Ce(OH)3 phases. X-ray photoelectron spectroscopy (XPS) has been employed to evaluate Ce species present in the different cerium oxide morphologies and to estimate their relative surface concentrations. As evident from Ce 3d core level spectra cerium oxide nanoparticles and nanocubes are basically CeO2 having Ce in the +4 oxidation state along with some amount of Ce3+ species. In contrast, Ce is in +3 oxidation state on its surface in cerium oxide nanofibers and rice grains that contain intermediate phases like Ce2O3 and Ce(OH)3 as endorsed by XRD patterns. CO oxidation has been carried out over these cerium oxide morphologies and among all morphologies lowest temperature CO oxidation has been demonstrated by the nanocube morphology.

Correction: Citrate combustion synthesized Al-doped CaCu3Ti4O12 quadruple perovskite: synthesis, characterization and multifunctional properties.

Correction for 'Citrate combustion synthesized Al-doped CaCu3Ti4O12 quadruple perovskite: synthesis, characterization and multifunctional properties' by Kamalesh Pal et al., Phys. Chem. Chem. Phys., 2020, 22, 3499-3511, DOI: 10.1039/C9CP05005A.

Growth of Carbon Dot-Decorated ZnO Nanorods on a Graphite-Coated Paper Substrate to Fabricate a Flexible and Self-Powered Schottky Diode for UV Detection.

The fabrication of flexible as well as self-powered optoelectronic devices is a growing and challenging area of research. Some scientists have reported the fabrication of either flexible or self-powered photodetectors recently. However, most of the literature studies fail to report the fabrication of self-powered as well as flexible photodetectors. This study reports the fabrication of self-powered, carbon dot (CD)-enhanced, flexible ZnO/graphite heterojunction-based UV detector where cellulose paper has been used as the substrate. A detailed study on the crystallinity and the defects of the ZnO nanorods has been done with appropriate characterizations. The CD-enhanced ZnO/graphite heterojunction showed Schottky characteristics. The Schottky parameters such as the barrier height, ideality factor, and the series resistance have also been calculated using the Cheung-Cheung method. The observed values of barrier height, ideality factor, and the series resistance are 0.74 eV, 3.74, and 503 kΩ, respectively. The transient response at self-powered condition has been demonstrated. The response time and the recovery time at self-powered condition have also been calculated with the help of the transient response, and those values are ∼2 and ∼3.2 s, respectively. The responsivity and the specific detectivity of the fabricated UV detector have been calculated as 9.57 mA/W and 4.27×108 Jones, respectively, at 330 nm wavelength, which is quite comparable with literature-reported values, considering a self-powered photodetector.

Risk Assessment of Cosmetics Using Triclosan on Future Generation's Germ Cell Maturation via Lactating Mother Rats.

Triclosan (TCS) is a widely used chemical in personal care and household products as an antimicrobial agent but some studies have reported it as being estrogenic. We investigated the influence of TCS on the male reproductive system of postnatal pups. Lactating mother rats (Rattus norvegicus) were given daily doses of 0 mg, 3 mg, and 5 mg/kg/day from the day of delivery until 28 days, equivalent to their natural breastfeeding duration. At 28 days, the male pups of all three groups were sacrificed and their biochemical parameters evaluated. TCS-treated pups had decreased mRNA levels for 3ß hydro-hydroxysteroid dehydrogenases (3ßHSD), OCT3/4, and androgen receptor (AR) (p < 0.05). The higher dose (5 mg/kg/day) male pups exhibited more significantly affected germ cell maturation and decreased body weight. In summary, TCS-treated lactating mothers passed the deleterious effects to their untreated male pups as exhibited by reduced androgens synthesis and subsequently decreased sperm count.

Enhancing photocatalytic degradation of quinoline by ZnO:TiO2 mixed oxide: Optimization of operating parameters and mechanistic study.

This study focuses on the photocatalytic degradation of quinoline, a recalcitrant heterocyclic nitrogenous aromatic organic compound, using the mixed oxide ZnO-TiO2 photo-catalyst. Photo-catalysts were synthesized by the solid-state reaction method at different calcination temperatures of 400 °C, 600 °C, and 800 °C. Different analytical methods, including Field emission scanning electron microscope, Brunauer-Emmett-Teller surface area, X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy analysis were used for the catalyst characterization. The highest pore surface area of 57.9 m2g-1 was obtained for the photo-catalyst calcined at 400 °C. The effects of calcination temperature, solution pH, initial concentration, catalyst dose as well as irradiation time were studied. At the optimum condition, i.e., calcination temperature of 400 °C, pH ≈8 and catalyst dose of 2.5 gL-1, maximum quinoline degradation and total organic carbon (TOC) removal efficiency of ≈92% and ≈78% were obtained after 240 min for initial quinoline amount of 50 mgL-1. The 1st, 2nd, and nth-order kinetic models were applied to analyze the quinoline degradation rate. The photocatalytic mechanism was studied by drawing energy level diagram with the help of the band-gap structures of the ZnO and TiO2, potential of the free radicals like OH and O2 and HOMO-LUMO energy gap of the quinoline molecule. The proposed pathways of quinoline mineralization were suggested on the basis of the identified intermediates by the gas chromatograph-mass spectrometer analysis and scavenger study.

Coupled-substituted double-layer Aurivillius niobates: structures, magnetism and solar photocatalysis.

Development of layered perovskites for sunlight-driven catalysis has gained a lot of attention in contemporary inorganic materials research. While the compositional modifications of three-dimensional perovskites are ubiquitous, they are infrequent in the case of layered perovskites particularly with niobates when the perovskite layer thickness is low. We report here the solid state synthesis of a series of lead-free double-layer Aurivillius niobates, LaBi2Nb1.5M0.5O9 (M = Cr, Mn, Fe, Co), by adopting a heterovalent coupled substitution strategy with SrBi2Nb2O9. Rietveld structure refinements of the compounds using P-XRD data suggest the formation of 3dn transition metal incorporated double-layer Aurivillius niobates in the non-centrosymmetric A21am space group, isostructural with the parent. The compounds show optical absorption in the visible region with the absorption tail extending up to ∼650 nm and band gaps ranging from 2.25-2.94 eV. While the compounds show paramagnetic behaviour with no indication of magnetic phase transition or ordering in the temperature range 5-300 K, the Mn compound stabilizes with a low-spin (LS) configuration in contrast to all others (Cr, Fe and Co compounds), which adopt a high-spin (HS) configuration. The stabilization of the LS configuration (t42g) of the Mn compound occurs with eg → t2g electron redistribution due to the suppression of first-order Jahn-Teller (FOJT) distortion by the dominating second-order Jahn-Teller (SOJT) distortion of Nb5+ (4d0). The compounds exhibit photocatalytic rhodamine B degradation at pH 2 within 50-110 minutes under natural sunlight-irradiation and remain stable after five consecutive degradation cycles maintaining their activity largely intact. The heterovalent coupled substitution strategy adopted here will open up possibilities for transforming many other UV-active layered niobates into sunlight-active compounds without using toxic Pb or expensive Ag, while the paramagnetic nature of the compounds will be helpful in post-catalytic magnetic separation of the catalysts. It is believed that the electronic instability of the t32ge1g configuration of Mn due to competing FOJT and SOJT effects may have far-reaching consequences in modifying its magneto-structural and electron transport properties.

Citrate combustion synthesized Al-doped CaCu3Ti4O12 quadruple perovskite: synthesis, characterization and multifunctional properties.

The facile synthesis of the Al-doped CaCu3Ti4O12 quadruple perovskite, a well-known and vastly studied material for various technological applications, using the modified citrate combustion route along with structural, microstructural, and X-ray photoelectron spectroscopic (XPS) characterization and magnetic, dielectric and electrical properties has been investigated and reported here. The possible applications of the material as a Schottky barrier diode (SBD) in optoelectronic devices and as a catalyst in methanol steam reforming (MSR) reaction for hydrogen generation, hitherto unreported in the open literature, have also been explored. The compound is crystallized in the cubic body centered Im3[combining macron] space group and the particle size is found to be in nanodimension with rather narrow size distribution. The enhanced resistivity could be attributed to the grain boundary effect, and consequently, it exhibits better performance as a SBD compared to the undoped sample. Desired cationic composition with expected valence states within the probe range is confirmed by XPS analysis. A better catalytic activity towards MSR is noticed for the Al-doped CaCu3Ti4O12 compared to the undoped composition. These new findings, namely MSR activity and applicability in the Schottky device, have highlighted further the multifunctional nature of the material in energy related issues and would thus be of interest to the materials community searching for functional materials.