Bismuth oxycarbonate grafted NiFe-LDH supported on g-C3N4 as bifunctional catalyst for photoelectrochemical water splitting

In the present study, we report the synthesis of photoactive bismuth oxycarbonate (BOC, Bi₂O₂CO₃) grafted NiFe layered double hydroxide (LDH) supported on g-C₃N₄ (15 wt% of g-C₃N₄) by coprecipitation method. The band gap of this photoactive material is determined to be 1.7 eV. The Bi₂O₂CO₃ agglomerates are anchored on NiFe-LDH plates and g-C₃N₄ nanosheets intercalated between the LDH plates. This architecture helps in expediting electron transfer for hydrogen and oxygen evolution reactions. The pristine NiFe-LDH photoanode acquires bifunctional character because of Bi₂O₂CO₃ agglomerates and g-C₃N₄ embedded in the architecture of BOC/NiFe-LDH@g-C₃N₄. This is found to be an efficient photoanode for oxygen evolution and photocathode for hydrogen evolution reactions. The water splitting process occurs along the heterojunction formed between g-C₃N₄ nanosheets and Bi₂O₂CO₃ grafted NiFe-LDH. Further, an additional interfacial charge transfer aided by Bi₂O₂CO₃ results in S-scheme mechanism, which enhances the rate of photoelectrochemical hydrogen and oxygen evolution reactions.     

Synthesis of CuTi-LDH supported on g-C3N4 for electrochemical and photoelectrochemical oxygen evolution reactions

A nanocomposite CuTi layered double hydroxide (LDH) supported on g-C₃N₄ (15 wt% of g-C₃N₄) is facilely synthesized by hydrothermal method. There are electrostatic interactions between positive layers of CuTi-LDH and negatively charged inner g-C₃N₄ sheets. The nanocomposite and its precursors are characterized through various analytical techniques, which affirmed the presence of both g-C₃N₄ and CuTi-LDH characteristic features. The pore-enriched hybrid geometry of CuTi-LDH@g-C₃N₄ with high specific surface area (146 m²/g), and suitable band gap of 2.46 eV enables the nanocomposite to act as both an electrocatalyst and photoelectrocatalyst for oxygen evolution reaction (OER). Both the electrochemical and photoelectrochemical studies are done using 1 M KOH (pH = 13.6) with applied potential of ?0.2 V to 1.5 V vs. Ag/AgCl. The onset potential of CuTi-LDH@g-C₃N₄ for OER appears at η = 0.36 V in dark and η = 0.32 V under visible light illumination of 30 min. Also, Mott-Schottky analysis shows n-type semiconductor behaviour for CuTi-LDH@g-C₃N₄ and its precursors. The photoelectrochemical water oxidation proceeds by charge transfer across a Type II heterojunction formed between the CuTi-LDH and g-C₃N₄ materials.     

Low-Temperature Processing of PZT Thick Film by Seeding and High-Energy Ball Milling and Studies on Electrical Properties

Lead zirconate titanate thick film with molecular formula PbZr_0.52Ti_0.42O₃ (PZT) was prepared by a modified conventional sol–gel method through seeding and high-energy ball milling, resulting in perovskite phase formation at lower temperatures. The ball-milling time was optimized by keeping the seed particle loading (5 wt.%) constant in the sol–gel solution. This methodology helped in reduction of the crystalline phase formation temperature to 300°C, which is much lower than that reported in the literature (450°C). The well-established perovskite phase was confirmed by x-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) of PZT films revealed uniform and crystalline microstructure. Film prepared by this methodology showed higher spontaneous polarization (2.22 μC/cm²), higher capacitance (1.17 nF), and low leakage current density (18 μA/cm²). The results obtained from ferroelectric characterization showed a strong correlation with the XRD and SEM results.     

A novel method of unburned hydrocarbons and NOx gases capture from vehicular exhaust using natural biosorbent

Automobile emissions are composed of NO_x and unburned hydrocarbon that contribute significantly to major environmental and health issues. In this study, encapsulated Moringa oleifera beads (EMBs) were synthesized using Moringa oleifera pod powder that was cross-linked with calcium alginate and used as a biosorbent for reducing the emission gas concentrations from the single-cylinder diesel engine. The breakthrough curve was attained from single and double stage of fixed bed column by the influence of temperature ranging from (80°C–120°C) ± 5°C with a feed flow rate varying from 8 to 10 kg hr^–1 and bed height varying from 15 to 30 cm. Based on the experimental results, the maximum biosorption capacity (q_o) was found to be 14.45 and 123.51 mg g^–1 for HC and NO_x, respectively, and was obtained at 80°C–90°C with double stage of BH–30cm under flow rate of 8 kg hr^–1. Further, breakthrough curves were investigated, and the experimental data were fitted using well-established models like Thomas, Yoon–Nelson, and Wang models. In addition, mass transfer models like Weber–Morris and Boyd were investigated to identify the rate-limiting step of the overall biosorption process.     

A Novel Efficient Heuristic Based Localization Paradigm in Wireless Sensor Network

Wireless Personal Communications - Wireless sensor network (WSN) is applicable in all IoT applications, thus it has many advancements. However, it has many drawbacks like localization, link...     

Effect of negative functionalisation of gold nanorods on conformation and activity of human serum albumin

The theranostic applications of gold nanorods (AuNRs) are limited due to the presence of cytotoxic cetrimonium bromide (CTAB) stabiliser, leading to the instigation of alternate stabilisers like negatively charged polystyrene sulphonate (PSS). Despite previous reports suggesting the impact of PSS‐AuNRs on cells, their effect on the most abundant protein in plasma, i.e. human serum albumin (HSA), has not been studied before. Hence, the impact of PSS‐AuNRs on HSA was thoroughly examined using varied spectroscopic techniques. The absorbance and fluorescence spectroscopic findings suggested the extent of ground‐state complexation and tryptophan domain disruptions of HSA for different AuNR concentrations, which were also suggested based on size measurements and activation energy calculations for complex formation. Modifications in the hydrophobic environment of HSA were evaluated using synchronous fluorescence, whereas the secondary structural damages were explained using circular dichroism (CD) and FTIR analyses. Additional studies to analyse protein denaturation, fibrillation, esterase activity, and free thiol were carried out to understand structural and functional changes. The study suggested that PSS‐AuNRs showed concentration‐dependent alterations in HSA structure, but the extent of protein toxicity was considerably lesser for PSS‐AuNRs of similar dimensions compared to the data available for CTAB‐AuNRs; thus, highlighting that PSS‐AuNRs could be safer for biomedical applications.Inspec keywords: fluorescence, gold, nanomedicine, molecular biophysics, hydrophobicity, cellular biophysics, circular dichroism, nanorods, biomedical materials, enzymes, Fourier transform infrared spectraOther keywords: HSA structure, PSS‐AuNRs, CTAB‐AuNRs, gold nanorods, human serum albumin, cytotoxic cetrimonium bromide stabiliser, negatively charged polystyrene sulphonate, absorbance, fluorescence spectroscopic findings, size measurements, activation energy calculations, AuNR concentrations, ground‐state complexation, tryptophan domain disruptions, hydrophobic environment, secondary structural damages, circular dichroism, FTIR analyses, protein denaturation, fibrillation, esterase activity, free thiol, concentration‐dependent alterations, protein toxicity     

Optically Stimulated Artificial Synapse Based on Layered Black Phosphorus

The translation of biological synapses onto a hardware platform is an important step toward the realization of brain‐inspired electronics. However, to mimic biological synapses, devices till?date continue to rely on the need for simultaneously altering the polarity of an applied electric field or the output of these devices is photonic instead of an electrical synapse. As the next big step toward practical realization of optogenetics inspired circuits that exhibit fidelity and flexibility of biological synapses, optically?stimulated synaptic devices without a need to apply polarity?altering electric field are needed. Utilizing a unique photoresponse in black phosphorus (BP), here reported is an all?optical pathway to emulate excitatory and inhibitory action potentials by exploiting oxidation?related defects. These optical synapses are capable of imitating key neural functions such as psychological learning and forgetting, spatiotemporally correlated dynamic logic and Hebbian spike?time dependent plasticity. These functionalities are also demonstrated on a flexible platform suitable for wearable electronics. Such low‐power consuming devices are highly attractive for deployment in neuromorphic architectures. The manifestation of cognition and spatiotemporal processing solely through optical stimuli provides an incredibly simple and powerful platform to emulate sophisticated neural functionalities such as associative sensory data processing and decision making.