Background

Porous boron nitride fibers (PBNFs) show potentially important applications in solving environmental and energy problems, especially in wastewater treatment, air purification, and drug transport, due to their high specific surface area, large pore capacity, and high density of adsorption active sites. In all these applications, these materials are required to be highly stable in a range of chemical environments, especially in water.

Methods

In this paper, the stability of PBNFs in an aqueous environment is studied systematically for the first time, its hydrolysis mechanism is explored, and the factors affecting the stability of the material are summarized. Meanwhile, improvement measures and optimization schemes are given to prepare porous boron nitride-based materials with excellent performance.

Significant findings

It was found that the oxygen-containing reactive groups and the low crystallinity part of PBNFs can chemically react with water molecules and hydrolyze to form ammonium borate hydrate, resulting in the destruction of the microstructure of PBNFs, the reduction of specific surface area, and the change of chemical composition. Therefore, a method to improve the purity of PBNFs by functionalizing the unstable groups of PBNFs with the help of highly reactive NH₃ was proposed, and SN-PBNFs with water stability and active adsorption capacity were synthesized.