Dixit, Ambesh

The availability of safe drinking water in non-networked rural areas and disaster-affected zones is dependent on point-of-use water filters. This study describes the design and performance assessment of a personal portable ceramic water filter named “sip-up.” Four sample variants were made using clay, exfoliated graphite (EG), and sawdust as raw materials. Samples were made using a mold to ensure uniformity and sintered at 850 °C. The experimental results showed that the sample containing the maximum amount of sawdust had the highest porosity of 36.07 ± 1.8%, providing an average flow rate of 0.61 ml/min in passive mode. The average pore size radius of all variants varied in the range of 1–10 nm, classifying the material as having a mesoporous structure. Compressive test results indicate that the addition of an organic additive (sawdust) decreases the compressive strength of filters as compared to non-organic additives. It has been observed that the addition of EG to clay does not significantly improve water filtration parameters as compared to samples containing only sawdust and clay. However, due to the smaller pore size, samples containing EG performed better in E. coli removal as compared to sawdust-containing samples. The final prototype can act as a single-use personal water filtration device that can be inserted into any commercial water bottle, making it an affordable and effective solution for hikers, travelers, and natural disasters such as floods and cyclones.

Alkaline water electrolysis (AWE) assisted by renewable solar or wind power has become a viable and environmentally beneficial approach for producing green hydrogen on a commercial scale. However, the AWE process requires an active, cost-effective, and stable catalyst to overcome the problems associated with the sluggish reaction kinetics. Here, we present a binder-free, facile, one-step hydrothermal process for synthesizing vertically aligned ZnO nanorods of different aspect ratios on nickel foam (ZNr@NF) as an electrocatalyst. The synthesized optimal ZNr@NF-3 shows an overpotential of 412, 394, 271, 219, and 157 mV in different electrolyte solutions, i.e., neutral BS, 0.05 0.1, 0.5, and 1 M KOH, respectively. In optimum pH electrolyte (1 M KOH), ZNr@NF-3 provides an electrochemically active surface area of 204.50 cm2, and the Tafel slope is ∼109 mV dec-1. It substantiates the presence of more active sites on ZNr@NF-3, contributing to fast reaction kinetics with a turnover frequency (TOF) of ∼8.02 × 10-2Formula Presented at 157 mV overpotential. Further, the chronopotentiometry test signifies a stable performance of the synthesized electrocatalyst ZNr@NF-3 for the hydrogen evolution reaction. Thus, the present investigation suggests that ZNr@NF-3 may be a feasible and cost-effective electrocatalyst for green hydrogen production through the AWE process.

The biosensing industry has seen exponential growth in the past decade. Impact of biosensors in the current scenario cannot be overlooked. Cardiovascular diseases (CvDs) have been recognized as one of the major causes for millions of deaths globally. This mortality can be minimized by early and accurate detection/diagnosis of CvDs with the help of biosensing devices. This also presents a global market opportunity for the development of biosensors for CvDs. A vast variety of biosensing methods and devices have been developed for this problem. Most of commercially available platforms for CvD detection rely on optical (fluorometric and colorimetric analysis) techniques using serum biomarkers since optical testing is the gold standard in medical diagnosis. Field effect transistors-based biosensors, termed as Bio-FETs, are the upcoming devices for blood or serum analyte detection due to excellent sensitivity, low operational voltage, handheld device structure and simple chip-based operation. Further, the discovery of two dimensional (2D) materials and their integration with conventional FETs has improved the overvoltage problem, sensitivity and strict operating conditions as compared to conventional FETs. Graphene-FETs based biosensing devices have been proven as promising candidates due to their attractive properties. Despite the severe threat of CvDs which has further increased in post-covid era, the Bio-FET sensor studies in literature are still rare. In this review, we aim to provide a comprehensive view of all the multidisciplinary concepts related to 2D-BioFETs for CvDs. A critical review of the different platforms has been covered with detailed discussions of related studies to provide a clear concept and present status of 2D-BioFETs based CvD biosensors.

We demonstrated the resistive random-access memory (RRAM) characteristics in cost-efficient, single-step, and in-situ grown nanostructured mixed-phase CuxO (x = 1, 2) thin films, on a commercially available Cu sheet, fabricated using thermal treatment under ambient conditions. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements explain the surface morphology of grown mixed-phase CuxO thin film with substrate imprints. Fourier-transform Infrared spectroscopy confirmed the mixed phase of Cu2O and CuO of synthesized thin films. The fabricated Al/CuxO/Cu RRAM device showed bipolar digital resistive switching followed by analog resistive switching. The device showed a fast-switching speed of 250 ms, high endurance durability for 2500 cycles, and better retention of 103 s, respectively. The interconnected CuxO with Cu sheet provides efficient charge carrier migration from the bottom electrode to the active layer. The formed defect and trapped site are responsible for the resistive switching behavior. Thus, the present study provides a way to harness the potential of RRAM on either thermally treated Cu sheets or realizing a Cu thin film followed by low-temperature annealing, which can easily be integrated into existing electronic devices for data storage applications.

An effort has been made to comprehensively study the structural modification of the molybdenum trioxide (MoO3) thin film with 100 MeV, Ni7+. The MoO3 nanoparticles were synthesized by hydrothermal method and thin film of MoO3 was fabricated by spin coating technique. MoO3 thin film was subjected to irradiation with 100 MeV, Ni7+ beam with various fluences of 5 × 1012, 1 × 1013, and 3 × 1013 ions cm−2. The structural changes induced by ion beam irradiation were characterized using XRD diffraction, Raman, Fourier Transforms Infrared Spectroscopy (FTIR) UV–visible spectroscopy, and Atomic Force Microscopy (AFM). The synthesized thin film showed an orthorhombic phase and the average crystallite size was 63.8 nm of the pristine sample. it is observed that the crystallinity decreases after irradiation. The Raman study confirmed the XRD findings and also showed that after exposure, intensity of the Raman peaks decreased and the width of the spectra expanded due to a decrement in the crystallinity. The bandgap of the thin films decreased after irradiation as the ion fluence increased up to 3 × 1013 ions cm−2. The findings showed that the ion beam irradiation was directly accountable for the amorphization and lattice defect development in the MoO3 thin films.

Rechargeable iron-ion batteries (RIIBs) are considered one of the alternatives to lithium-ion batteries (LIBs) owing to their high volumetric energy density and low-cost fabrication under ambient conditions. A crucial aspect of RIIBs lies in developing high-performance cathode materials with high cycling stability and fast charge-discharge characteristics. We developed highly stable iron oxide microspheres (Fe3O4-MS) via solvothermal synthesis. Various electrochemical measurements were performed, including cyclic voltammetry (CV) to understand the redox mechanism and diffusion characteristics of iron-ions, galvanostatic charging discharging (GCD) for cycling stability analysis, and electrochemical impedance spectroscopy (EIS) for different electrode resistance analyses. RIIBs exhibit a high specific capacity of 155 mA h g−1 at 25 mA g−1 and 60 mA h g−1 at a higher current density of 500 mA g−1 (∼8C), with 92% retention capacity and fast charge-discharge characteristics. Electronically powered gadgets were used to demonstrate the practical utility of RIIBs. The remarkable electrochemical performance observed due to highly stable Fe3O4-MS is confirmed by ex situ characterization after the complete cycling of the cell compared to pristine electrodes, and these results strongly correlated with impedance analysis. Thus, the present work facilitates the development of an efficient cathode material for RIIBs.