**Author details**

Tawfik A. Saleh\*

Address all correspondence to: tawfik@kfupm.edu.sa

Chemistry Department, Center of Excellence in Nanotechnology, King Fahd University of Petroleum & Minerals, Saudi Arabia

### **References**

**•** The presence of the nanotubes in the composite can inhibit the recombination of photo-

**•** The transmission stability of promoted electron between the nanotubes and the conduc‐ tion band is enhanced by the strong interaction and intimate contact between the nano‐

The chapter discusses the preparation of the nanocomposites consisting of carbon nanotubes and metal oxides like titania, zinc oxide and tungsten trioxide. For the preparation of such composite, the oxygen-containing groups are grafted on the surface of the nanotubes by acid treatment. This is followed by the attachment of the metal oxides nanoparticles on the nano‐ tubes surface. The chapter also highlights the means by which the composite is character‐ ized. These include Fourier transform infrared spectroscope, X-ray powder diffraction, field emission scanning electron microscope, energy dispersive X-ray spectroscope and transmis‐

The UV, visible light and sunlight photocatalytic activity of the CNT-based nanocomposites is higher than that of the metal oxide or mechanical mixture of the metal oxide and CNTs. CNTs are considered to be good support materials for semiconductors like TiO2, ZnO and WO3 because nanotubes provide a large surface area support with high quality active sites. Also they stabilize charge separation by trapping electrons, thereby hindering electron–hole

The author would like to acknowledge the support of Chemistry Departments, Center of Re‐ search Excellence in Nanotechnology & King Fahd University of Petroleum and Minerals,

Chemistry Department, Center of Excellence in Nanotechnology, King Fahd University of

recombination by modification of band-gap and sensitization.

(KFUPM) Dhahran, Saudi Arabia, for this work.

Address all correspondence to: tawfik@kfupm.edu.sa

Petroleum & Minerals, Saudi Arabia

generated electrons and holes, thus, improving the photocatalytic activity.

particles and the surface of the nanotubes.

488 Syntheses and Applications of Carbon Nanotubes and Their Composites

**4. Conclusion**

sion electron microscope.

**Acknowledgements**

**Author details**

Tawfik A. Saleh\*


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**Chapter 22**

**Carbon Nanotubes for Energy Applications**

The energy crisis during the 1970s sparked the development of renewable energy sources and energy conservation measures. As supply eventually met demand, these programs were scaled back. Ten years later, the hazards of pollution led to work on minimisation and reversal of the environmental impact of fossil fuel extraction, transport and consumption [1]. The United States Department of Energy predicts that 20 years from now, the world's energy consumption will increase by 20% (Figure 1). The growing concerns over the con‐ stant use of fossil fuels and its effect on climate change [2], has once again spurred re‐ search on sustainable energy development and on enhancement in renewable energy systems. Advances in energy storage and conversion systems that will make our energy usage more efficient are essential if we are to meet the challenge of global warming and the finite nature

The need for the development of efficient energy storage systems is paramount in meet‐ ing the world's future energy targets, especially when energy costs are on the increase and more people need access to electricity [4, 5]. Energy storage technologies can improve effi‐ ciencies in supply systems by storing the energy when it is in excess, and then release it at a time of high demand [4]. Further material progression in research and development fundamentals, as well as engineering improvements need to be continued in order to cre‐ ate energy storage systems that will help alleviate humanities energy storage and conver‐

> © 2013 Antiohos et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2013 Antiohos et al.; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Dennis Antiohos, Mark Romano, Jun Chen and

Additional information is available at the end of the chapter

Joselito M. Razal

**1. Introduction**

**1.1. The energy problem**

of fossil fuels [2, 3].

sion dilemmas.

http://dx.doi.org/10.5772/51784
