1. School of Environmental and Chemical Engineering Yanshan University Qinhuangdao 066004 Hebei China
2. School of Materials Science and Engineering Nanyang Technological University Singapore 639798 Singapore
3. Department of Materials Science and Engineering City University of Hong Kong Hong Kong SAR 999077 China
4. Center of Super-Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong SAR 999077 China