Operando Two-Dimensional Solid-State NMR Unveils Dual-Template Collaboration and Competition in SAPO-34 Zeolite...

Area of Science:

• Materials Science
• Chemical Engineering
• Spectroscopy

Background:

• Zeolite crystallization mechanisms, especially with dual-template agents, are complex and challenging to study.
• Understanding these mechanisms is crucial for designing efficient synthesis methods.

Purpose of the Study:

• To investigate the crystallization mechanism of SAPO-34 zeolite using advanced operando NMR techniques.
• To elucidate the roles of dual-template agents and their interactions during zeolite formation.

Main Methods:

• Introduction of novel operando two-dimensional (2D) solid-state NMR spectroscopy under high temperature and high pressure.
• Utilized operando 2D ³¹P{¹H} HETCOR and ²⁷Al{¹H} HMQC NMR techniques.
• Employed operando ¹H, ²⁷Al, and ³¹P MAS NMR.

Main Results:

• Clarified intricate cooperative and competitive interactions between dual-template agents.
• Highlighted synergistic effects between templates and hydroxyl groups during CHA zeolite crystallization.
• Revealed a previously unreported induction period preceding intermediate formation.

Conclusions:

• The study provides unprecedented insights into SAPO-34 zeolite crystallization at an atomic level.
• Advances the understanding of molecular dynamics, crystallization mechanisms, and zeolite synthesis methods.
• Represents a significant leap forward in the application of operando 2D solid-state NMR spectroscopy.