Nucleation of ITQ-21 Studied by ESI-MS

The nucleation pathway of zeolite ITQ-21 was studied by using electrospray ionization mass spectrometry (ESI-MS). The syntheses were performed with different silicon to germanium ratios and with different mineralizing agents. Silicate species with structural characteristics of the obtained material were found to occur already in solution, immediately before nucleation. In addition, by using fluoride (F−) or hydroxide ions (OH−) as mineralizing agents, it was possible to determine their influence on the nucleation pathway. In particular, a reaction-rate-accelerating rather than a structure-directing effect was determined for F−.