1. Institute
of Applied Physics and Materials Engineering, University of Macau, Macao SAR, P. R. China
2. Department
of Electromechanical Engineering, Faculty of Science and Technology, University of Macau, Macao SAR, P. R. China
3. Department
of Materials Science and Engineering, Shenzhen Key Laboratory of Hydrogen
Energy, South University of Science and Technology of China, Shengzhen 518055, Guangdong P. R. China
4. Institute
of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology, and Research), #08-03, 2 Fusionopolis Way, Innovis, Singapore 138634
5. Department
of Materials Science and Engineering, National University of Singapore, Singapore 119077