Facile synthesis of Cr doped hierarchical ZnO nano-structures for enhanced photovoltaic performance

Insights into the compositional and temperature-mediated magnetic characteristics of chromium-doped ZnO nanoparticles

This study explores the influence of chromium content and temperature on the magnetic characteristics of ZnO synthesized via the cost-effective coprecipitation approach. The host ZnO structure is not significantly changed by chromium doping, even at 5 wt.% of chromium concentration, according to x-ray diffraction studies. The Zn-O characteristic stretching vibration band at 480 cm-1and the other functional group attached to the Cr-doped ZnO nanoparticles are confirmed by Fourier-transform infrared (FTIR) spectroscopy studies. Diffuse reflectance spectroscopy analysis shows the interaction between chromium ions and ZnO causes bandgap narrowing, and the observed optical bandgap values fall as chromium content increases in the host ZnO matrix. Point defects such as zinc interstitial, zinc vacancy, and oxygen vacancy that exist in the Cr-doped ZnO nanoparticles are inveterate through photoluminescence spectroscopy. Vibrating sample magnetometry investigations reveal weak ferromagnetic behavior at low applied fields and diamagnetic signatures dominating at high applied fields in the Cr-doped ZnO nanoparticles at 300 K. The magnetic characteristics are also tunable in terms of temperatures, which opens new avenues for fabricating dilute magnetic semiconductors with various applications.

CdAl4O7/CdO nanocomposites: green tea extract-mediated sol-gel auto-combustion synthesis, characterization, and study as a potential hydrogen storage material

In this article, we present the synthesis of binary CdAl4O7/CdO nanocomposites using green tea extracts and green chemistry methods for high-performance hydrogen storage. The green tea extract contains bioactive compounds (polyphenols) that act as reducing agents, which facilitate the reaction between metal ions and water. By examining the structural and morphological characteristics of the obtained substrates using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR), it was demonstrated that the nanocomposites were successfully synthesized. We evaluated the electrochemical performance of the synthesized CdAl4O7/CdO nanocomposites using a three-electrode chronopotentiometry system. According to the results, the synthesized nanocomposites are capable of storing 1750 mAh/g of hydrogen at a constant current of 1 Amp. By using green tea extract as a natural structure-directing agent, the CdAl4O7/CdO nanocomposite can be developed more sustainably as high-performance hydrogen storage materials. Ultimately, this work contributes to the advancement of sustainable energy storage through the synthesis of a promising new material.

Fabrication and Characterization of Acute Myocardial Infarction Myoglobin Biomarker Based on Chromium-Doped Zinc Oxide Nanoparticles

In this article, we describe the fabrication and characterization of a sensor for acute myocardial infarction that detects myoglobin biomarkers using chromium (Cr)-doped zinc oxide (ZnO) nanoparticles (NPs). Pure and Cr-doped ZnO NPs (13 × 10¹⁷, 20 × 10¹⁷, and 32 × 10¹⁷ atoms/cm³ in the solid phase) were synthesized by a facile low-temperature sol-gel method. Synthesized NPs were examined for structure and morphological analysis using various techniques to confirm the successful formation of ZnO NPs. Zeta potential was measured in LB media at a negative value and increased with doping. XPS spectra confirmed the presence of oxygen deficiency in the synthesized material. To fabricate the sensor, synthesized NPs were screen-printed over a pre-fabricated gold-coated working electrode for electrochemical detection of myoglobin (Mb). Cr-doped ZnO NPs doped with 13 × 10¹⁷ Cr atomic/cm³ revealed the highest sensitivity of ~37.97 μA.cm⁻²nM⁻¹ and limit of detection (LOD) of 0.15 nM for Mb with a response time of ≤10 ms. The interference study was carried out with cytochrome c (Cyt-c) due to its resemblance with Mb and human serum albumin (HSA) abundance in the blood and displayed distinct oxidation potential and current values for Mb. Cr-doped ZnO NP-based Mb biosensors showed 3 times higher sensitivity as compared to pure ZnO NP-based sensors.

Recent progress on fabrication methods of graphene-based membranes for water purification, gas separation, and energy sustainability

Graphene-based layered materials have got significant interest in membrane technology for water desalination, gas separation, organic nanofiltration, pervaporation, proton exchange applications, etc. and show remarkable results. Up to date, various methods have been developed for fabrication of high performance membrane. Most of them are only suitable for research purposes, but not appropriate for mass transport barrier and membrane applications that require large-area synthesis. In this comprehensive review, we summarized the current synthesis and fabrication methods of graphene-based membranes. Emphasis will be given on fabrication of both graphene-based nanoporous and lamellar membranes. Finally, we discuss the current engineering hurdles and future research directions yet to be explored for fabrication of such membranes.

Modeling RSM of photocatalytic treatment of Acid Red 18 pollutant using ZnO–Cr nano-photocatalyst, kinetic studies, and energy management

The ZnO–Cr nano-photocatalyst was synthesized using a microwave-assisted solution combustion method and applied for the photodegradation of the organic pollutant Acid Red 18 (AR18). The synthesized nano-photocatalyst was characterized by XRD, FESEM, EDX, and FTIR methods. To reach the optimal condition of the treatment, the response surface methodology was used in the central composite design model. The amount of nano-photocatalyst, pH of the solution, and initial concentration of the pollutant were optimized. The polynomial 3-degree model was fitted to the photodegradation data, and the correlation coefficients of the model showed an interaction between the parameters. Optimization of the polynomial model for pollutant treatment was investigated under the same conditions, and the comparison of the observed and predicted treatment models showed a low difference in decolorization. The intermediates were identified by liquid chromatography/mass spectrometry. A kinetic study showed that the first-order kinetic constant for the degradation of pollutant concentrations from 10 to 30 mg L−1 changed from 0.0178 to 0.0058 min–1. Finally, economic evaluation and energy management of the process showed that the decolorization process was more economical at low pollutant concentrations.

Review elucidating graphene derivatives (GO/rGO) supported metal sulfides based hybrid nanocomposites for efficient photocatalytic dye degradation

Photocatalysis by utilizing semiconductors for the removal of toxic pollutants has gained tremendous interest for remediation purposes. The organic pollutants usually include; pesticides, dyes and other phenolic compounds. An imperative restraint associated with the photocatalytic effectiveness of the catalyst is the rapid recombination of the light generated electrons and holes. The particle agglomeration and electron-hole recombination hinders the rate of pollutant removal. For decades, researchers have used metal-sulfides efficiently for photocatalytic dye degradation. The recent use of hybrid nanomaterials with the combination of graphene derivatives such as graphene oxide and reduced graphene oxide (GO/rGO)-metal sulfide has gained interest. These composites have displayed an impressive upsurge in the photocatalytic activity of materials. The current review describes the various researches on dye photodegradation by employing (GO/rGO)-metal sulfide, exhibiting a boosted potential for photocatalytic dye degradation. A comprehensive study on (CuS, ZnS and CdS)–GO/rGO hybrid composites have been discussed in detail for effective photocatalytic dye degradation in this review. Astonishingly improved dye degradation rates were observed in all these studies employing such hybrid composites. The several studies described in the review highlighted the varying degradation rates based on diverse research parameters and efficacy of graphene derivatives for enhancement of photocatalytic activity.

Dynamic green synthesis of iron oxide and manganese oxide nanoparticles and their cogent antimicrobial, environmental and electrical applications

The scientific community is inclined towards addressing environmental and energy concerns through sustainable means. Conventional processes such as chemical synthesis, involve the usage of environmentally harmful ligands and high tech facilities, which are time-consuming, expensive, energy-intensive, and require extreme conditions for synthesis. Plant-based synthesis is valuable and sustainable for the ecosystem. The use of plant-based precursors for nanoparticle synthesis eliminates the menace of toxic waste contamination. The present review elucidates that the plant based synthesized iron oxide and manganese oxide nanoparticles have tremendous and exceptional applications in various fields such as antimicrobial and antioxidative domains, environmental, electrical and sensing properties. Hence, the literature reviewed explains that plant based synthesis of nanoparticles is an adept and preferred technique. These important transition oxide metal nanoparticles have great applicability in ecological, environmental science as well as electrochemistry and sensing technology. Both these metal oxides display a stable and adaptable nature, which can be functionalized for a specific application, thus exhibiting great potential for efficiency. The current review epitomizes all the latest reported work on the synthesis of iron and manganese oxide nanoparticles through a greener approach along with explaining various significant applications keeping in view the concept of sustainability.

Graphene-based composite membranes for isotope separation: challenges and opportunities

Graphene-based membranes have got significant attention in wastewater treatment, desalination, gas separation, pervaporation, fuel cell, energy storage applications due to their supreme properties. Recently, studies have confirmed that graphene based membranes can also use for separation of isotope due to their ideal thickness, large surface area, good affinity, 2D structure etc. Herein, we review the latest groundbreaking progresses in both theoretically and experimentally chemical science and engineering of both nanoporous and lamellar graphene-based membrane for separation of different isotopes. Especially focus will be given on the current issues, engineering hurdles, and limitations of membranes designed for isotope separation. Finally, we offer our experiences on how to overcome these issues, and present an ideas for future improvement and research directions. We hope, this article is provide a timely knowledge and information to scientific communities, and those who are already working in this direction.

Recent progress in decontamination system against chemical and biological materials: challenges and future perspectives

Environmental contamination is one of the key issues of developing countries in recent days, and several types of methods and technologies have been developed to overcome these issues. This paper highlights the importance of decontamination in a contaminated environment that normally precedes protection, detection and identification followed by medical support. Further, this paper especially focuses on individual and collective NBC decontamination required on navy ships and correspondingly presents solutions (viable and economical) through the use of indigenously developed decontamination equipment. The paper also highlights the integration of various decontamination technologies with pre-existing ship decontamination systems, indicating the need for various decontaminants. Finally, we will also focus on new decontamination systems based on nanomaterials and enzymes and their utilization.

Innovatory role of nanomaterials as bio-tools for treatment of cancer

Conventional treatment modes like chemotherapy, thermal and radiations aimed at cancerous cells eradication are marked by destruction pointing the employment of nanomaterials as sustainable and auspicious materials for saving human lives. Cancer has been deemed as the second leading cause of death on a global scale. Nanomaterials employment in cancer treatment is based on the utilization of their inherent physicochemical characteristics in addition to their modification for using as nano-carriers and nano-vehicles eluted with anti-cancer drugs. Current work has reviewed the significant role of different types of nanomaterials in cancer therapeutics and diagnostics in a systematic way. Compilation of review has been done by analyzing voluminous investigations employing ERIC, MEDLINE, NHS Evidence and Web of Science databases. Search engines used were Google scholar, Jstore and PubMed. Current review is suggestive of the remarkable performance of nanomaterials making them candidates for cancer treatment for substitution of destructive treatment modes through investigation of their physicochemical characteristics, utilization outputs and long term impacts in patients.