1. Material and Mineral Research Unit Faculty of Engineering Universiti Malaysia Sabah Jalan UMS 88400 Kota Kinabalu Sabah Malaysia
2. Institute of Advanced Materials Jiangxi Normal University 99 Ziyang Avenue Nanchang Jiangxi 330022 China
3. Institute of Carbon Science and Technology Shinshu University 4‐17‐1 Wakasato Nagano 380‐8553 Japan