**Author details**

Kai Li1,2, Ji Chen<sup>1</sup> \* and Dan Zou1

\*Address all correspondence to: jchen@ciac.jl.cn

1 State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, PR China

2 University of Science and Technology of China, Hefei, Anhui, China
