Cu/CuO@ZnO Hollow Nanofiber Gas Sensor: Effect of Hollow Nanofiber Structure and P-N Junction on Operating Temperature and Sensitivity

Prussian Blue Analogues-Derived ZnFe2O4 in CuO/ZnFe2O4 p-n Junction for H2 Production

ZnFe2O4 is an n-type semiconductor spinel oxide with promising applications in various fields, including photocatalysis. This study reports the successful synthesis of a novel ZnFe2O4 derivative based on Prussian Blue Analogues (PBAs) through an electrosynthesis method. To enhance photocatalytic performance, the synthesized ZnFe2O4 was employed as a cocatalyst in p-n junction materials, specifically CuO/ZnFe2O4. Our findings reveal that introducing ZnFe2O4 could significantly improve the photocatalytic activity and hydrogen (H2) production rate of the CuO/ZnFe2O4 system compared to bare CuO. This enhancement was sustained over an extended operational period, indicating the material's potential for long-term use in photocatalytic applications. The superior performance of the ZnFe2O4 cocatalyst is attributed to its efficient charge separation and improved light absorption properties, which collectively contribute to higher photocatalytic efficiency. This study highlights the potential of PBA-based derivative ZnFe2O4 as an effective cocatalyst in developing advanced photocatalytic systems for sustainable hydrogen production.

Chemoresistive Gas Sensors Based on Electrospun 1D Nanostructures: Synergizing Morphology and Performance Optimization

Gas sensors are essential for safety and quality of life, with broad applications in industry, healthcare, and environmental monitoring. As urbanization and industrial activities intensify, the need for advanced air quality monitoring becomes critical, driving the demand for more sensitive, selective, and reliable sensors. Recent advances in nanotechnology, particularly 1D nanostructures like nanofibers and nanowires, have garnered significant interest due to their high surface area and improved charge transfer properties. Electrospinning stands out as a promising technique for fabricating these nanomaterials, enabling precise control over their morphology and leading to sensors with exceptional attributes, including high sensitivity, rapid response, and excellent stability in harsh conditions. This review examines the current research on chemoresistive gas sensors based on 1D nanostructures produced by electrospinning. It focuses on how the morphology and composition of these nanomaterials influence key sensor characteristics-sensitivity, selectivity, and stability. The review highlights recent advancements in sensors incorporating metal oxides, carbon nanomaterials, and conducting polymers, along with their modifications to enhance performance. It also explores the use of fiber-based composite materials for detecting oxidizing, reducing, and volatile organic compounds. These composites leverage the properties of various materials to achieve high sensitivity and selectivity, allowing for the detection of a wide range of gases in diverse conditions. The review further addresses challenges in scaling up production and suggests future research directions to overcome technological limitations and improve sensor performance for both industrial and domestic air quality monitoring applications.

Application and Development of Electrospun Nanofiber Scaffolds for Bone Tissue Engineering

Nanofiber scaffolds have gained significant attention in the field of bone tissue engineering. Electrospinning, a straightforward and efficient technique for producing nanofibers, has been extensively researched. When used in bone tissue engineering scaffolds, electrospun nanofibers with suitable surface properties promote new bone tissue growth and enhance cell adhesion. Recent advancements in electrospinning technology have provided innovative approaches for scaffold fabrication in bone tissue engineering. This review comprehensively examines the utilization of electrospun nanofibers in bone tissue engineering scaffolds and evaluates the relevant literature. The review begins by presenting the fundamental principles and methodologies of electrospinning. It then discusses various materials used in the production of electrospun nanofiber scaffolds for bone tissue engineering, including natural and synthetic polymers, as well as certain inorganic materials. The challenges associated with these materials are also described. The review focuses on novel electrospinning techniques for scaffold construction in bone tissue engineering, such as multilayer nanofibers, multifluid electrospinning, and the integration of electrospinning with other methods. Recent advancements in electrospinning technology have enabled the fabrication of precisely aligned nanofiber scaffolds with nanoscale architectures. These innovative methods also facilitate the fabrication of biomimetic structures, wherein bioactive substances can be incorporated and released in a controlled manner for drug delivery purposes. Moreover, they address issues encountered with traditional electrospun nanofibers, such as mechanical characteristics and biocompatibility. Consequently, the development and implementation of novel electrospinning technologies have revolutionized scaffold fabrication for bone tissue engineering.

Advanced functional nanofibers: strategies to improve performance and expand functions

Nanofibers have a wide range of applications in many fields such as energy generation and storage, environmental sensing and treatment, biomedical and health, thanks to their large specific surface area, excellent flexibility, and superior mechanical properties. With the expansion of application fields and the upgrade of application requirements, there is an inevitable trend of improving the performance and functions of nanofibers. Over the past few decades, numerous studies have demonstrated how nanofibers can be adapted to more complex needs through modifications of their structures, materials, and assembly. Thus, it is necessary to systematically review the field of nanofibers in which new ideas and technologies are emerging. Here we summarize the recent advanced strategies to improve the performances and expand the functions of nanofibers. We first introduce the common methods of preparing nanofibers, then summarize the advances in the field of nanofibers, especially up-to-date strategies for further enhancing their functionalities. We classify these strategies into three categories: design of nanofiber structures, tuning of nanofiber materials, and improvement of nanofibers assemblies. Finally, the optimization methods, materials, application areas, and fabrication methods are summarized, and existing challenges and future research directions are discussed. We hope this review can provide useful guidance for subsequent related work.

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Morphology genetic 3D hierarchical SnO2microstructures constructed by Sub 5 nm nanocrystals for highly sensitive ethanol-sensor

SnO₂is widely used for ethanol-sensing applications due to its excellent physicochemical properties, low toxicity and high sensitivity. However it is a challenge to construct 3D-hierarchical structures with sub 5 nm primary grain particle, which is the optimized size for ethanol sensor. Herein, genetic tri-level hierarchical SnO₂microstructures are synthesised by the genetic conversion of 3D hierarchical SnS₂flowers assembled by ultrathin nanosheets. The SnS₂nanosheets are morphology genetic converted to porous nanosheets with sub 5 nm SnO₂nanoparticles during the calcination process. When used for the detection of ethanol, the sensor exhibits a high sensitivity of 0.5 ppm (R_a/R_g = 6.8) and excellent gas-sensing response (R_a/R_g= 183 to 100 ppm) with short response/recovery time (12 s/11 s). The excellent gas sensing performance is much better than that of the previous reported SnO₂-based sensors. The highly sensitivity is attributed to the large surface area derived from the recrystallization and volume changes, which offers more active sites during the morphology genetic conversion from SnS₂to SnO₂. Furthermore, the flower-like 3D structure enhances the stability of the materials and is beneficial for the mass diffusion dynamics of ethanol.

Effect of the Morphology and Electrical Property of Metal-Deposited ZnO Nanostructures on CO Gas Sensitivity

The development of a highly sensitive gas sensor for toxic gases is an important issue in that it can reduce the damage caused by unexpected gas leaks. In this regard, in order to make the sensor accurate and highly responsive, we have investigated which morphology is effective to improve the sensitivity and how the deposited nanoparticle affects the sensitivity by controlling the morphology of semiconductor oxides—either nanorod or nanoplate—and depositing metal nanoparticles on the semiconductor surface. In this study, we compared the CO gas sensitivity for sensors with different morphology (rod and plate) of ZnO nanostructure with metal nanoparticles (gold and copper) photodeposited and investigated the correlation between the gas sensitivity and some factors such as the morphology of ZnO and the properties of the deposited metal. Among the samples, Au/ZnO nanorod showed the best response (~86%) to the exposure of 100 ppm CO gas at 200 °C. The result showed that the electrical properties due to the deposition of metal species also have a strong influence on the sensor properties such as sensor response, working temperature, the response and recovery time, etc., together with the morphology of ZnO.

Special Issue "Advanced Nanomaterials Based Gas Sensors"

During the last several years, according to the works published in research journals, many nanostructured materials have been tested as sensing materials for gas-sensing applications. This trend has been observed for both metal oxides as well as carbon-based nanomaterials. More recently, it has also been extended to other materials based on chalcogenides. The field of applications for these sensors is very wide, including air quality, industrial safety and medical diagnosis, using different transducing mechanisms. Therefore, in this Special Issue, we have put together recent advances in this area.

Nanoporous hybrid CuO/ZnO/carbon papers used as ultrasensitive non-enzymatic electrochemical sensors

In this research, we demonstrate a facile approach for the synthesis of a graphite-analogous layer-by-layer heterostructured CuO/ZnO/carbon paper using a graphene oxide paper as a sacrificial template.