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This study presents a comprehensive investigation into the synthesis, characterization, and application of an exceptionally sensitive electrochemical sensor designed for the ultrasensitive detection of 2,4-dinitrotoluene (DNT), a notorious explosive compound. The sensor employs bimetallic nickel-cobalt oxide (NiCo2O4) nanoparticles, synthesized through a facile hydrothermal method. Extensive analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS), were employed to validate the crystallinity and purity of the NiCo2O4 nanoparticles. These nanoparticles, possessing remarkable properties, form the core of our electrochemical sensor, enabling it to offer heightened sensitivity and selectivity even under ambient conditions. Most notably, this sensor boasts an impressively low limit of detection (LOD) of 18 nM, coupled with a broad linear detection range (LDR) spanning from 10 nM to 100 nM. The sensor exhibits robust sensitivity, excellent selectivity, and an outstandingly low detection threshold, collectively demonstrating its potential for precise and accurate detection of DNT. This research underscores the significant potential of bimetallic oxide nanoparticles, specifically NiCo2O4, in the precise quantification of nitro-aromatic analytes. This study opens up promising avenues for assessing hazardous compounds in complex environmental matrices, thereby contributing to the advancement of electrochemical sensing. Additionally, this novel sensing platform holds substantial promise for enhancing security measures and environmental monitoring through its improved sensitivity and selectivity in the detection of explosives.

The escalating discharge of noxious gases resulting from unmitigated anthropogenic activities has emerged as a pivotal concern, presenting imminent threats to global ecosystems. In response to this pressing challenge, the development of cutting-edge materials within gas sensor systems emerges as a promising avenue for the precise detection of hazardous gaseous pollutants. This investigation delves into the synthesis and characterization of a novel composite material: reduced graphene oxide (rGO) modified with ruthenium Octaethyl porphyrin (Ru OEP), with a primary focus on its chemiresistive sensing properties. The meticulously deposited rGO-modified Ru OEP material onto gold microelectrodes, featuring a 3 µm gap on a silicon Si/SiO2 substrate, resulted in an intricate two-terminal chemiresistive sensor device. Comprehensive structural, spectroscopic, and morphological analyses were conducted to elucidate the intricacies of the composite material. The electrical characterization, evaluated through I-V measurements, provided nuanced insights into the device's resistance properties. Notably, the chemiresistive sensor demonstrated exceptional responsiveness to Carbon monoxide (CO) gas, exhibiting an impressively low limit of detection (LOD) at 2.5 ppm. The fabricated sensor showcased rapid response and recovery times, registering at 43 s and 65 s, respectively, underscoring its efficiency in real-time applications. Furthermore, the sensor maintained linearity and stability across a broad spectrum of conditions, ensuring prolonged reliability and consistent performance. This research underscores the potential of advanced materials, specifically the rGO-modified Ru OEP composite, in crafting highly effective gas sensors to address urgent environmental and safety concerns. The presented findings contribute invaluable insights to the burgeoning field of gas sensor technology, paving the way for innovative solutions to mitigate the adverse impacts of anthropogenic activities on our delicate ecosystems.

Significant advances in the field of energy storage have enabled scientists to explore highly stable electro-active electrodes for high-performance supercapacitors. The present investigation describes the synthesis of well-ordered NiMoO4 nanowalls at 140 °C using hydrothermal synthesis, which was then grown directly on Ni foam with different reaction times. The resulting NiMoO4 nanowalls were utilized as electro-active electrodes for electrochemical supercapacitor applications. The reaction time was found to be a critical factor in achieving the ordered NiMoO4 nanowalls on the Ni foam, and at a reaction time of 12 h, the nanosheets self-organized into a nanowall-like morphology over the Ni foam. Pure NiMoO4 crystal phases with less surface imperfections were produced by the 12-hour reaction time, as demonstrated by the compositional, structural, and crystalline characteristics. As an electro-active electrode, the NiMoO4 electrode with a 12-hour reaction time showed the highest specific capacitance of 357.6 Fg−1 at 0.01 Vs−1 compared to NiMoO4 electrodes with reaction times of 6h (53.06 Fg-1 at 0.01 Vs−1) and 20h (55.4 Fg-1 at 0.01 Vs−1). The NiMoO4 electrode also demonstrated exceptional stability in an alkaline electrolyte, exhibiting less deterioration in multicycles CV after 100 repeated cycles. The excellent electrochemical properties of the NiMoO4 electrode are attributed to its unique ordered nanowall structure, which improves surface area and electrical conduction, accelerating fast redox reactions. These properties make it a promising material for use in pseudocapacitors, with implications for high-performance energy storage solutions in industrial sectors.

The radiation-protection properties of the magnetic semiconducting quaternary compounds Cu2CoGeS4, Cu2CoGeSe4, and Cu2CoGeTe4 were examined in this study by using Phy-X/PSD software with the selected gamma energy (0.015–15 MeV). The radiation shielding coefficients such as mass and linear attenuation coefficients (MAC) and (LAC), half-value layer (HVL), and mean free path (MFP) of the present semiconductors were calculated. Also, the total electronic and atomic cross-sections (ECS and ACS), the effective atomic number (Zeff), the effective electron density (Neff), and the effective conductivity (Ceff) of these semiconductors were estimated to see how well they could protect against radiation. A comparative study occurred between the obtained results and the corresponding values of RS-253-G18, RS-360, RS-520 glasses, barite, chromite, and ferrite concrete. The results show that semiconducting samples with the best shielding performance outperform RS-253-G18, RS-360 glass, and RS-520 glass materials commonly used in nuclear applications. The Cu2CoGeTe4 sample had the highest MAC, LAC, and ACS, as well as the highest ECS and Zeff values. The other two semiconductor samples had the lowest MAC, ECS, and Zeff values. For photons, charged particles (electrons, protons, alpha particles), and C-ion, Phy-X/PSD allows the calculation of the Zeff quickly and precisely across the entire energy range. This study indicates that the semiconductor samples can be utilized as radiation attenuators for various nuclear fields.