1. College of Materials Science and Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University, Changsha 410082, China
2. Chemistry Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt
3. Nanotechnology Research Centre, Sultan Qaboos University, PO Box 17, PC 123, SQU, Al-Khoudh, Oman