Self-standing Substrates

Despite there are structures invisible for the human eye, they mastered the world of advanced electronic devices, sensors, novel cosmetics or drugs. When the dimensions of the materials go down to the nanometres scale, their properties change dramatically comparing to the observable objects. Because of their tiny size, they gained the name of nanomaterials but simultaneously their importance has significantly grown up. Nanomaterials exhibit superb features such as a distinctive catalytic activity, hydrophobicity, photoconversion activity and biological affinity. Following that, even a small amount of nanomaterials is sufficient to provide unusual properties to the final products such as coatings, active layers in solar cells, clothes, electrodes and electrolytes used for energy storage devices. Owing to the rapid development in the synthesis methods and characterization techniques, especially those used for morphology inspection, we can investigate them in details on the molecular scale and describe the mechanism that stays behind improved antimicrobiological activity, hydrophobicity, capacitance or catalytic properties. Despite the number of usable elements is limited, the diversity of morphologies, namely rods, particles, tubes, planes and the possibility of heterostructures formation, provides researchers the wide room for maneuverer. Sometimes, only small change in the material geometry, structure or a little amount of introduced dopant atoms is enough to obtain completely new nanomaterial that has not been known so far. Therefore, we should not be surprised how fast surrounding environment is changing and our everyday life is supported by the novelties from the nano world. The aim of this chapter is to present the diversity of nanomaterials taking into account their dimensions, shape and composition. Herein, particles, tubes, wires, pores, walls, exhibiting at least one dimension within the nanoscale will be evoked. Moreover, the nanostructures that morphology reminds well known objects from nature are discussed. The description of some interesting examples is supported by the extraordinary SEM images illustrating the beauty unavailable for naked eye.

Self-supported materials or often called as self-standing, free-standing, and self-assembly materials is an emerging class of materials that have been applied in various application. Owing to a unique structured or sometimes known as hierarchical structures have improved the specific properties of the materials. In the case of catalysis application, the self-supported catalyst has significantly enhanced the specific chemical reaction due to the ability to provide more reaction active site. In this chapter, the application of self-supported materials for photo and photoelectrolysis application is highlighted and discussed. The various promising fabrication self-supported photocatalyst and photoelectrode is introduced and discussed. On the of that, the various potential application of self-supported materials in the field of photocatalysis technology such as water and wastewater treatment, hydrogen production, and carbon dioxide reduction are discussed in detail.

Recent advancements in nanotechnology largely enabled fabrication of plasmonic nanostructures of desired structural features and substantially improved the sensitivity and selectivity of the conventional optical sensing techniques. The plasmonic nanostructure mitigates the limitation of weak scattering cross-section in Raman spectroscopy via electromagnetic as well as chemical enhancement mechanism. The plasmonic nanostructure combined with the Raman spectroscopy technique, popularly known surface-enhanced Raman scattering spectroscopy, has been now established as an effective tool for molecular finger printing of analyte molecule and find applications diverse areas, ranging from biosensors to art. This chapter explains the mechanism behind the surface-enhanced Raman scattering spectroscopy with an emphasis on the factors contributing towards the enhancement in the Raman signal. Further, an account of the difference between conventional and surface enhanced Raman spectroscopy is presented. The role of hot spots and the rationale behind the choice of metal nanoparticles for surface-enhanced Raman scattering substrates is described. In addition, various approaches adopted for the fabrication of substrates in 1D, 2D, and 3D is explained in detail. A detailed account of a few emerging areas wherein this technique finds applications is also given in the chapter.

This chapter discusses the utilization of ultrafiltration membrane (UF) in water treatment system. The UF membrane overview including the type, preparation and characterization is concisely reviewed. The two major types of membrane namely polymeric and ceramic membranes are subdivided into two distinguished subchapters focusing on their fabrication and physicochemical properties. Additionally, the main converge of this chapter is the application of these UF membranes on multidisciplinary industries such as textile, dairy, beverages, microelectronics, petrochemical, cosmetic and pharmaceutical, and few others. The advantages and limitations of UF carefully addressed in their respective subchapters. At the end of this chapter, an attempt is also made to show the future direction of the UF membrane towards the advance membrane technology system such as membrane distillation, membrane contactor and many others.

This book chapter presents the information on conducting polymers and their applications. Conducting polymers are the class of polymeric material which was discovered in 1977, and since then these become the exciting topic of new research. Their preparation methods, advantages, applications have been studied extensively. The excellent properties of conductive polymers have enabled them to be used in and as a sensor, energy storage devices, solar cells, fuel cells, lithium ion batteries, supercapacitors, microwave absorption, electrorheological fluids, light emitting diode and separation membrane. Adsorption is the most commonly used method for water treatment because of its numerous advantages. The results show that the conductive polymers have effective adsorptive properties towards various heavy metal ions and thus can be applied for the remediation of toxic pollutants from wastewater.

Due to depletion of fossil fuels, development of large-scale ground-breaking energy conversion technology like fuel cells, water splitting, air batteries etc. needs pertinent catalyst to ease the process of conversion of chemical energy to electrical energy with greater efficiency in low time consuming. In this chapter, we will discuss the role of self-supported catalyst, which are now trending the era of nanotechnology in electrocatalysis. Self-supported catalyst can be grown on soft substrate, hard substrate or can be free standing. Self-supported electrocatalyst does not needs binder for their attachment on the conductive surface of other electrodes like glassy carbon electrode, platinum electrode, graphite electrode. They have various unique properties like flexible electrode surface, large number of active sites, high electrical conductivity, better catalytic performances, and stability in any pH electrolytic solution. They render much hassle-free electrode synthesis procedure than the powdery electrode material. This chapter mainly focuses on the benefits of using self-supported electrodes in various energy application like water splitting, oxygen reduction reaction (ORR), CO₂ reduction reaction, fuel cells. It has been observed that the self-supported electrocatalyst proves to be the superior electrocatalyst in the immense area of electrocatalysis.

In the recent days the demand of portable, thin and flexible electronics such as roll-up display, touch screen, smart electronics and wearable sensors, are drawing a great interest in the daily life of human being because of advancement in materials and technology. In order to simplify this growing electronic demand, super capacitor is fascinating as a favourable energy storage devices. Supercapacitor has more power density, faster charge-discharge cycle and higher energy storage capacity with compare to Li-ion batteries. Recently, flexible super capacitor is the main focus in the flexible electronics due to its higher flexibility, high power density and high capacitance performance. Conducting polymers based supercapacitor is more promising candidate compare to other materials in terms of their flexibility, high redox active specific capacitance and essential elastic nature. In this chapter different conducting polymer (CPs) based super capacitor have been explained.

Drawing inspiration from living organisms, inorganic self-healing substrates are the smart materials to revolutionize our world in the next decades. These smart substrates inherit the ability to detect damage and autonomously or non-autonomously heal and restore to its pristine state. The consequence of self-healing offers new route towards sustainable, safer and long lasting materials for multifunctional applications, such as: medicine, energy, construction, food packaging, water treatment and textiles. This chapter explores the preparation of the self-healing substrates from inorganic substrates such as polymers, ceramics and metals; including their healing chemistries and envisioned applications.

There is an increasing demand on the fabrication of robust, flexible, cost-effective, and eco-friendly self-supporting materials, such as yarns, fibers, papers-like, films, and monoliths, etc., due to their promising applications in flexible sensing fields. With the unique structure and outstanding properties, various functional materials with zero-dimensional, one-dimensional, and two-dimensional structures have been employed as promising building blocks for the assembly of self-supporting materials. In this chapter, the type, key parameter, and working principles of sensors are presented. Meanwhile, we summarize the sensing properties of different self-supporting materials through detailed cases. In addition, the challenges and opportunities of current sensors based on self-supporting materials are briefly discussed.

Rapid growth of flexible/wearable electronic devices has encouraged the swift development in the direction of fabricating high performance flexible supercapacitors with superior electrochemical performance. Recently, graphene based electrodes have received a great deal of attention for flexible supercapacitors on account of their outstanding properties; including excellent mechanical flexibility, enormous surface area and high electrical conductivity. This chapter summarizes the recent research progress on flexible supercapacitors and identifies the existing challenges related to preparation of electrodes and their device fabrication with regulated electrical and electrochemical properties. Furthermore, it draws attention towards the recent flexible prototype supercapacitors, in plane supercapacitors and fiber-type supercapacitors development. Moreover, it aims for insightful understanding on opportunities and challenges, endowing stimulation of further research progress in this fascinating field.

Free standing graphene belongs to the pioneering group of carbonaceous nanomaterial and has gained large appreciation in the field storage and conversion of energy. Free standing or self-supported graphene materials are made up of dense graphene sheets arranged in the form of three dimensional structures like foam, films, monoliths, papers, and aerogels with hierarchical porous structure. In last few decades, speedy growth in the binder free graphene based super-capacitors can be credited to their influential properties like flexibility, large surface to volume ratio, high mechanical durability, electrical and thermal conductivity, and light weight. The free standing graphene also delivers us with short and easy diffusion pathway for ions (generated from electrolytes), channels for electron transport and composites with active materials which provide a synergistic effect. This chapter will provide the information about synthesis of free standing graphenes and their recent advancements as the efficient electrode materials for supercapacitors.

Exploiting from tremendously abundant and inexpensive sodium reservoirs, sodium ion batteries (NaIBs) are estimated as reassuring candidate for electrochemical energy conservation and storage on large scale. Owing to larger radius and atomic mass of Na⁺ than conventionally used materials, NaIBs having inorganic electrode encounter with little capacity and inadequate cycle life. Development of environment friendly, renewable, abundant raw material based batteries are gaining much attention. Organic electrode based sodium ion batteries are one of them. Presently, a lot of work is done on functionalizing organic electrodes, incorporation of nanostructured materials to tune their electrochemical properties. In collation, organic electrode exhibit merits like high capacity, structural design ability and lesser cationic radius limitations. Organic electrodes plagued with solubility issues in electrolytes and lesser conductivity. Here in organic electrodes based on their reactions are divided into three classes; C=O based than C–N=O based and then doping reactions are systematically viewed. In this chapter we summarize the research work to put forward organic electrode material for NaIBs. The conductivity issue can be resolved through increasing conjugated structures. Theoretical capacity can be elevated by expanding active groups. Working voltage can be regulated by tuning grafting overseeing lowest unoccupied molecular orbital (LUMO). Future of organic electrode relies mainly on aprotic electrolyte based full NaIBs with long cycle life.