One-Dimensional Metal Oxide Nanostructures for Chemical Sensors

The fabrication of chemical sensors based on one-dimensional (1D) metal oxide semiconductor (MOS) nanostructures with tailored geometries has rapidly advanced in the last two decades. Chemical sensitive 1D MOS nanostructures are usually configured as resistors whose conduction is altered by a charge-transfer process or as field-effect transistors (FET) whose properties are controlled by applying appropriate potentials to the gate. This chapter reviews the state-of-the-art research on chemical sensors based on 1D MOS nanostructures of the resistive and FET types. The chapter begins with a survey of the MOS and their 1D nanostructures with the greatest potential for use in the next generation of chemical sensors, which will be of very small size, low-power consumption, low-cost, and superior sensing performance compared to present chemical sensors on the market. There follows a description of the 1D MOS nanostructures, including composite and hybrid structures, and their synthesis techniques. And subsequently a presentation of the architectures of the current resistive and FET sensors, and the methods to integrate the 1D MOS nanostructures into them on a large scale and in a cost-effective manner. The chapter concludes with an outlook of the challenges facing the chemical sensors based on 1D MOS nanostructures if their massive use in sensor networks becomes a reality.

Aqueous Mg-Ion Supercapacitor and Bi-Functional Electrocatalyst Based on MgTiO3 Nanoparticles

Supercapacitor and hydrogen-based fuel cells are cheap and environmental-friendly next-generation energy storage devices that are intended to replace Lithium-ion batteries. Metal oxide nanostructures having perovskite crystal structure have been found to exhibit unique electrochemical properties owing to its unique electronic band structure and multiple redox-active ions. Herein, MgTiO3 nanoparticles (MTO-1) were synthesized by wet-chemical sol–gel technique with an average particle size of 50–55 nm, which exhibited superior supercapacitor performance of capacitance (C) = 25 F/g (at 0.25 A/g), energy density (ED) = 17 Wh/kg, power density (PD) = 275 W/kg and 82.41% capacitance retention (after 1000 cycles). Aqueous 1 M Mg(ClO4)2 solution was used as the electrolyte. MTO-1 revealed an overpotential (η) = 1.329 V and Tafel slope (b) = 374 mV/dec towards Oxygen Evolution Reaction (OER) electrocatalyst and exhibited η = 0.914 V and b = 301.4 mV/dec towards Hydrogen Evolution Reaction (HER) electrocatalyst, both in presence of alkaline 1 M KOH solution, making these MgTiO3 nanoparticles very promising for potential use in various technologically important electrochemical applications.

Recent Developments in Nanomaterials Based Adsorbents for Water Purification Techniques

Currently, most advanced technologies employ nanomaterials due to the modern tailor-made properties these materials exhibit compared to their bulk counterparts. Nanomaterials have attracted researchers around the globe in the last few decades due to their unusual properties due to the presence of a greater number of carriers at the surface, which affects the chemical and physical properties of these materials. Ensuring pure drinking water for domestic purposes is the biggest challenge in current times. Industrialization is increasing with time due to human needs. The extensive use of fertilizers to enhance agricultural productivity has hazardous effects on the ecosystem. Water pollution will significantly impact living beings on the land and aquatic beings, followed by terrestrial, aerial flora, and fauna. In a world full of technologies, there are many methods to purify water (water filters, RO purifiers, etc.). Still, nanotechnology plays a vital part in purifying water on a large scale. Nanotechnology methods came up with new materials and analytical techniques that can treat the by-products that are toxic to the environment. Heterogeneous photocatalysis used with metal oxide nanostructures causes no harm to the ecosystem. Nanomembranes and Nanostructures will play an active role by acting as a trap for many Nano pollutants. This review presents nano cellulose, nanocarbon tubes, and nanomembranes used in water purification and analytical techniques by addressing the current economic water purification techniques.

Bioinspired Nanomaterials

Biological synthesis employing microorganisms, fungi or plants is an alternative method to produce nanoparticles in low-cost and eco-friendly ways. The book covers the synthesis of metal nanoparticles, metal oxide nanostructures and nanocomposite materials, as well as the stability and characterization of bioinspired nanomaterials. Applications include optical and electrochemical sensors, packaging, SERS and drug delivery processes.

Recent Advances in Non-Enzymatic Glucose Sensors Based on Metal and Metal Oxide Nanostructures for Diabetes Management- A Review

There is an undeniable growing number of diabetes cases worldwide that have received widespread global attention by many pharmaceutical and clinical industries to develop better functioning glucose sensing devices. This has called for an unprecedented demand to develop highly efficient, stable, selective, and sensitive non-enzymatic glucose sensors (NEGS). Interestingly, many novel materials have shown the promising potential of directly detecting glucose in the blood and fluids. This review exclusively encompasses the electrochemical detection of glucose and its mechanism based on various metal-based materials such as cobalt (Co), nickel (Ni), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), titanium (Ti), iridium (Ir), and rhodium (Rh). Multiple aspects of these metals and their oxides were explored vis-à-vis their performance in glucose detection. The direct glucose oxidation via metallic redox centres is explained by the chemisorption model and the incipient hydrous oxide/adatom mediator (IHOAM) model. The glucose electrooxidation reactions on the electrode surface were elucidated by equations. Furthermore, it was explored that an effective detection of glucose depends on the aspect ratio, surface morphology, active sites, structures, and catalytic activity of nanomaterials, which plays an indispensable role in designing efficient NEGS. The challenges and possible solutions for advancing NEGS have been summarized.