Hexagonal boron nitride hollow capsules with collapsed surfaces: Chemical vapor deposition with single-source precursor ammonium fluoroborate

Li Xiaopeng¹, Zhang Jun¹, Yu Chao¹, Liu Xiaoxi¹, Abbas Saleem¹, Li Jie¹, Xue Yanming^{2, †,}, Tang Chengchun^{1, ‡,}

XRD patterns of the samples: (a) SBA-15 treated with the gaseous ammonium fluoroborate at different temperatures; (b) the corresponding samples with identical washing process by concentrated NaOH solution.