Acknowledgments This work is supported by the National Natural Science Foundation of China (Grand No. 21271114); Tsinghua University independent research and development fund (20111080982) and Program for Changjiang Scholars and Innovative Research Team in University (IRT13026).
TNAs (Titanium dioxide nanotube arrays) were synthesized by electrochemical anodization and these TNAs were annealed in different gas atmosphere such as argon, air, hydrogen and nitrogen. This annealing in different...