Investigating synergistic cooperativity of metal-Brønsted acid site pair in MFI-type zeolites by synchrotron X-ray powder diffraction

Abstract

Atomistic engineering of active sites with multiple functional motifs has gained significant attention in heterogeneous catalytic science due to their potential synergistic cooperativity. While these catalysts have demonstrated superior performance in various applications, a lack of systematic study hampers the understanding of intricate synergism. In this study, we present a comprehensive investigation into the synergistic cooperativity between a combination of metal sites (M = Fe³⁺ and Cu²⁺) and dominant Brønsted acid sites (BASs, X = B, Ga, and Al) in MFI-type zeolites with delicate control over their quantities and respective distribution. By employing two model catalytic reactions that simultaneously utilize the two active motifs in proximity, we examined the cooperativity required to modulate catalytic reactivity. Combined synchrotron X-ray powder diffraction and theoretical evidence revealed the synergism and the respective contribution of the active pairs of metal-BAS within molecular distances.