Abstract:

Chlorine anion (Cl-) emission from the synthesized microporous crystal surface of C12A7-Cl- (11CaO·7Al2O3·CaCl2) was observed by time-of-flight mass spectrometry (TOF-MS). We investigated the emission features of C12A7-Cl- (including branching ratios of emission intensity, temperature effect, electric field effect, and apparent activation energy) in detail. The anionic species emitted from the C12A7-Cl - surface were dominant by Cl- anions (maximum branching ratio of intensity: 98%) while a weak O- anion emission and electron emission were also observed. The emission current densities of the anionic species were significantly enhanced by the increase of sample surface temperature or extraction electric field strength. The apparent activation energies for the Cl- emission decreased from 180.9 to 110.0 kJ·mol-1 as the extraction electric field strength increased from200 to 1200 V·cm-1. The binding energy between the Cl- anion and the C12A7-Cl- surface was about 228 kJ·mol-1. The stability of the Cl- emission was also investigated and an electrochemistry implantation method was adopted to obtain a sustainable Cl- emission. We also discussed the formation and emission mechanism of Cl- anions based on the above investigations. This method may be potentially useful to develop a reservoir or generator of Cl- anions.

Key words: Chlorine anion, C12A7-Cl-, Emission feature, Electrochemistry implantation