Bifunctional Strategy Coupling Y₂O₃-Catalyzed Alkanal Decomposition with Methanol-to-Olefins Catalysis for Enhanced Lifetime

Bifunctional strategies exploiting the selective and catalytic decomposition of formaldehyde by Y₂O₃ improve the lifetime of CHA zeotypes and zeolites for methanol-to-olefins catalysis 4-fold, as quantified by total turnovers, without disrupting the inherently high selectivity to light olefins. The improvement in catalyst lifetime increases with increasing proximity between H⁺ sites of the zeotype/zeolite and the surface of the rare earth metal oxide. This proximity effect demonstrates crucial transport of formaldehyde between and within zeotypic/zeolitic domains on catalyst lifetime. These results provide mechanistic insights revealing formaldehyde as an accelerant for the initiation and termination of chain carriers and exemplify a strategy for designing improved methanol-to-olefins catalysts by optimizing (bi)functionality and reaction-transport dynamical phenomena. (Chemical Equation Presented).