23. Y. Zheng, S. Chen, H. Song, H. L. Guo, K. A. I. Zhang*, C. Zhang*, T. X. Liu. Nitrogen-doped hollow carbon nanoflowers from a preformed covalent triazine framework for metal-free bifunctional electrocatalysis. Nanoscale 2020, 12, 14441-14447. [2020-23.pdf]