Frustrated Brønsted Pairs: A Kind of Highly Active but Neglected Site in HZSM-5 Zeolite.

Frustrated Lewis Pairs (FLPs) have been well-established as highly efficient catalytic sites that function through electron transfer from Lewis base to Lewis acid coupled with substrate activation. Inspired by the catalytic mechanism of FLPs, we identify a previously overlooked pattern of frustrated brønsted pairs (FBPs) in HZSM-5 zeolite, which function via a concerted proton transfer paradigm. This FBP active site comprises two conjugate structures whose interconversion drives swift hydrogen transfer in substrates, thereby enabling the highly efficient catalysis of a variety of hydrogen-involved reactions and exhibiting unique dynamic behavior. Simulations of the methanol-to-hydrocarbons process, including isomerization, addition, decomposition, and substitution reactions, reveal that FBPs can dramatically smooth the free-energy profile and reduce the energy span by nearly 1.00 eV. This work establishes the novel catalytic pattern of FBPs and uncovers its pivotal role in zeolite catalysis.