Adsorption properties of various forms of aluminium trifluoride investigated by PulseTA®

The current study employs the Pulse Thermal Analysis (PTA) method to investigate the adsorption of gaseous methanol onto various forms of aluminium trifluoride drawing special attention to the strongly adsorbing β-AlF3 and the recently described high-surface (HS) AlF3. Simultaneously or subsequently occurring physisorption and chemisorption can be clearly distinguished and partly quantified. BET surface and NH3-TPD data will be discussed together with the surface coverage by methanol determined by TA. The extraordinary sorptive properties of HS-AlF3 are due to acidic sites at the remarkably large surface. The crystalline modifications η-AlF3, θ-AlF3, and κ-AlF3 are less-important as they poorly adsorb exhibiting thermogravimetric curves without clearly expressed mass changes. Their surface loading is comparably poor as found for the stable modification α-AlF3.