Nanotechnology and Photocatalysis for Environmental Applications

Muhammad Bilal Tahir, Muhammad Rafique, Muhammad Shahid Rafique

• Publisher: Elsevier
• Year: 2020
• Print ISBN: 9780128211922
• eBook ISBN: 9780128211977
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Nanotechnology and Photocatalysis for Environmental Applications focuses on nanostructured control, synthesis methods, activity enhancement strategies, environmental applications, and perspectives of semiconductor-based nanostructures. The book offers future guidelines for designing new semiconductor-based photocatalysts, with low cost and high efficiency, for a range of products aimed at environmental protection. The book covers the fundamentals of nanotechnology, the synthesis of nanotechnology, and the use of metal oxide, metal sulfide, and carbon-based nanomaterials in photocatalysis. The book also discusses the major challenges of using photocatalytic nanomaterials on a broad scale.The book then explores how photocatalytic nanomaterials and nanocomposites are being used for sustainable development applications, including environmental protection, pharmaceuticals, and air purification. The final chapter considers the recent advances in the field and outlines future perspectives on the technology. This is an important reference for materials scientists, chemical engineers, energy scientists, and anyone looking to understand more about the photocatalytic potential of nanomaterials, and their possible environmental applications.- Explains why the properties of semiconductor-based nanomaterials make them particularly good for environmental applications- Explores how photocatalytic nanomaterials and nanocomposites are being used for sustainable development applications, including environmental protection, pharmaceuticals, and air purification- Discusses the major challenges of using photocatalytic nanomaterials on a broad scale

Chapter 1: History and fundamentals of nanoscience and nanotechnology

Muhammad Rafique^a; Muhammad Bilal Tahir^b; Muhammad Shahid Rafique^c; M. Hamza^{b a} Department of Physics, University of Sahiwal, Sahiwal, Pakistan
^b Department of Physics, University of Gujrat, Gujrat, Pakistan
^c Department of Physics, University of Engineering and Technology, Lahore, Pakistan

Abstract

Nanoscience is the study of material on the scale of nanometers, and nanotechnology is the application of nanoscience. The pioneer of nanoscience and technology is not known, however, Richard Feynman is credited with introducing the revolutionary concepts of modern nanotechnology. The change in particle size, grain size, and boundary of nanomaterials revolutionized the field. Smaller particle size and greater surface area distinguish nanomaterials from and make them superior to bulk-sized materials. It is observed that electrical, mechanical, magnetic, and thermal properties are improved with nanosized materials. Nanoparticles also enhance the optical properties in semiconductor and metal nanoparticles. The small size of nanoparticles may cause quantum size effects, so quantum mechanics rules are implemented in nanoscience. Scientists are engaged in the production of devices based on principles of quantum mechanics and nanotechnology, which are expected to revolutionize the world.

Keywords

Nanotechnology; Nanostructures; Properties; Quantum effects

1.1: What is nanoscience and nanotechnology

The word “Nano” is from the Greek word meaning “very small.” Nanoscience is the study of systems with very small dimensions. It combines chemistry, material science, and biology. Nanoscience can be defined as:

1. 1. The study of materials/substances with at least one dimension on the nanometer (10^{− 9} m) [1] scale.
2. 2. How to design, build, and control systems manufactured with material on the scale of nanometers.

Nanoscience is an interdisciplinary field requiring the mutual cooperation of biologists, chemists, and physicists to understand and solve various scientific issues as shown in Fig. 1.1 [2, 3]. Nanotechnology is the application of nanoscience and hence is defined as:

1. 1. The design, synthesis, characterization, and applications of materials, devices, and systems while controlling the size and shape at nanoscale.
2. 2. The production and application of materials systems on a nanoscale.

Fig. 1.1 Relationship between nanoscience and major fields.

Nanotechnology deals with the manufacture of materials with atomic precision. The difference between nanoscience and nanotechnology (N&N) is the same as the difference between science and technology, but in N&N ultra-high precision is required [4]. N&N as defined by the United States National Foundation [5, 6] is the study that relies on various key parameters to control the synthesis procedure for the fabrication of materials with dimensions ranging from 1 to 100 nm. These materials have properties to form layered, large, and novel structures by combining with each other in very different ways.

The important feature of N&N is the drastic change in properties of materials (i.e., chemical, physical, mechanical, thermal) from their bulk counterparts as the size of materials approaches to nanoscale. These nanomaterials show drastically enhanced properties compared to bulk materials when used in similar applications. The applications of nanotechnology in different fields like electronics, biology, and environmental applications are increasing rapidly [7, 8].

1.1.1: Importance and future of nanoscience and nanotechnology

Nanotechnology is about the synthesis, characterization, and applications of materials and structures at scale ranges from 1 to 100 nm where 1 nm is 1 billionth of a meter and a thousand times smaller than a micron (1 nm = 10 Angstroms (Å)). The smallness of the nanometer scale can also be understood by the fact that the diameter of a human hair is 10,000 times thicker than a nanometer, and the diameter of a hydrogen atom is 1/10th of a nanometer. The unique properties of nanomaterials make them useful in different applications including solar cells, supercapacitors, and photocatalysis.

There are various reasons that make N&N so important.

1. (i) The continued variation in size strongly influences the electric properties of materials. The different macroscale and microscale properties of the materials, including charge storage capacity, magnetization, and other properties, are enhanced through designing the material at nanoscale.
2. (ii) The fabrication mechanism of assembler (nano factories)–based nanodevices has great potential to develop effective systems and energy devices.
3. (iii) Their increased surface area and surface-to-volume ratio gives nanomaterials superior properties, making them useful in different applications. The nanoscale is potentially able to reduce the size of devices such as quantum computers, optoelectronic devices, renewable energy devices, and sensors. The ubiquity of very high-speed Internet servers and cellular telephones is due to the replacement of nanoprocessors by microprocessors. These digital processors proved efficient in accomplishing many logical tasks from disease diagnostics to surveillance swiftly and effortlessly.
4. (iv) The promising impact of nanotechnology in a number of different areas, including bionanotechnology, tissue engineering, food and agricultural industries, cosmetics, bioinformatics, information technology, and many others.

Nanomaterials and devices improved by research in the field have wider applications and improved efficiency. Therefore, new avenues have opened for industries with the promising integration of atoms, photons, and biological cells through nanotechnology. The special economic, social, and environmental benefits will continue to be obtained from advanced research and development of technology [9–12].

1.2: History and background

The exact history of nanotechnology is still unknown, and although Richard Feynman is considered the pioneer scientist in the field, this is not necessarily true. Prior to Feynman, nanomaterials were already being used for different applications, such as in medicine. John Utynam patented gold nanoparticle-based glass in 1449. In the 16th century, Theophrastus von Hohenheim, a Swiss doctor better known as Paracelsus, used gold nanoparticles to treat patients suffering from various ailments. Therefore, the field of N&N is not new, but its methods have advanced over time.

Richard Zsigmondy was the first to introduce the concept of the nanometer, and he received the Noble Prize in Chemistry in 1925 for measuring the size of particles, such as gold colloidal particles, using a microscope. As mentioned, Feynman did not introduce the concept of nanotechnology, although he did elaborate on it in 1959 through his lecture at an international conference. Norio Taniguchi introduced the term “nanotechnology” in 1974 to describe the different processing mechanisms of nanosized materials and for the description of accuracy of super thin materials up to nanoscale. The birth of clusters in colloidal science and the invention of the Scanning Tunneling Microscope (STM) encouraged more work in nanotechnology. This series of successes did not stop, and only after a small period of time, fullerenes and carbon nanotubes were invented. These accomplishments opened new avenues of research and led researchers and scientists into new areas full of potential for using nanotechnology.

In the United States, two initiatives in 1991 and 2001 were taken for awareness of potential applications of nanotechnology. Beyond the programs already mentioned, a survey by the International Center for Te...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Preface
• Chapter 1: History and fundamentals of nanoscience and nanotechnology
• Chapter 2: Nanostructure materials and their classification by dimensionality
• Chapter 3: Synthesis methods of nanostructures
• Chapter 4: Photocatalysis fundamentals
• Chapter 5: Nanomaterials for photocatalysis
• Chapter 6: Metal oxide- and metal sulfide-based nanomaterials as photocatalysts
• Chapter 7: Carbonaceous nanomaterials as photocatalysts
• Chapter 8: Photocatalytic nanomaterials for degradation of organic pollutants and heavy metals
• Chapter 9: Photocatalytic nanomaterials for hydrogen evolution from water splitting
• Chapter 10: Photocatalytic nanomaterials for CO2 photoreduction and disinfection of bacteria
• Chapter 11: Photocatalytic nanomaterials for the removal of pharmaceuticals
• Chapter 12: Photocatalytic nanomaterials for air purification and self-cleaning
• Chapter 13: Recent advances in the development of photocatalysis and future perspectives
• Index