1. Nanotechnology Research Center Sultan Qaboos University PO Box 17 Al‐Khoud PC 123 Oman
2. Chemistry Department, Faculty of Science Fayoum University Fayoum 63514 Egypt
3. Chemistry Department Government College University Lahore Lahore 54000 Pakistan
4. Department of Chemical and Petroleum Engineering College of Engineering Sultan Qaboos University P. O. Box 33, Al Khould Muscat PC 123 Oman
5. College of Materials Science and Engineering Hunan University Changsha 410082 China