The creation of heteroatom nodes in zeolite frameworks
is a challenging
but rewarding pathway to superior materials for numerous catalytic
applications. Here, we present a novel method for precise control
over heteroatom incorporation by in situ anodic release of a desired
metal during hydrothermal zeolite synthesis. The generic character
of the technique and the applicability of the new synthesis reactor
are shown across 3 zeolite structures crystallized and 4 electrode
metals in two pH zones and by offering access to a new mixed-metal
zeolite. The timed and voltage-controlled metal release offers a minimized
interference between the metal precursor state and critical events
in the zeolite’s crystallization. A mechanistic study for Sn-MFI
revealed the key importance of controlled release: while keeping its
concentration lower than in batch, a lot more Sn can be incorporated
into the framework. The method grants access to 10× increased
framework Lewis acid site densities (vs batch controls) for the most
relevant stannosilicates. As a proof, the electro-made materials demonstrate
higher productivity than their classic counterparts in lactate catalysis.
This innovative approach effectively expands the synthesis space of
zeolites.