1. Energy Safety Research Institute, Swansea University, Bay Campus, Swansea SA1 8EN, U.K.
2. College of Engineering, Swansea University, Bay Campus, Swansea SA1 8EN, U.K.
3. Materials Research and Technology Institute, University of Texas at El Paso, El Paso, Texas 79968, United States
4. Department of Physics, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, U.K.
5. Department of Chemistry and Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States
6. Faculty of Engineering, Universiti Teknologi Brunei, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam