Mesoporous boron nitride in contact with water - chemical stability and adsorption properties

In this research project we synthesized two different porous boron nitrides - a mesoporous one (BN-meso) and a reference micro-mesoporous one (BN-ref). Our goal was to identify the influence of different pore sizes towards the chemical stability of these materials. We focussed mainly on water, as it is present in a significant amount of industrial adsorption applications. The samples were exposed to humid air, water vapor and liquid water for multiple weeks. Prior to and after this exposure we characterized the materials with XRD, XPS, SEM, mercury intrusion, ATR-IR, TG and nitrogen sorption. Additionally, we calculated pore size distributions using QSDFT for the adsorption branch of nitrogen sorption at 77 K on carbon with slit and cylindrical pores. Based on the water vapor adsorption isotherms and pore size distributions we conclude that mesoporous BN ist stable against water in the vapor phase. Micro-mesoporous BN is stable neither towards vapor nor liquid water.