Effect of framework composition and NH3 on the diffusion of Cu+ in Cu-CHA catalysts predicted by machine-learning accelerated molecular dynamics

• DOI: 10.48550/arxiv.2305.12896
• Publication Date: 2023-01-01
• Authors: Reisel Millán; Estefanía Bello‐J...; Manual Moliner; Mercedes Boronat; Rafael Gómez‐Bomb...
• Keywords: Reactivity

Cu-exchanged zeolites rely on mobile solvated Cu+ cations for their catalytic activity, but the role of framework composition transport is not fully understood. Ab initio molecular dynamics simulations can provide quantitative atomistic insight are too computationally expensive to explore large length- and time-scales or diverse compositions. We report a machine-learning interatomic potential that accurately reproduces ab results effectively generalizes allow multi-nanosecond supercells chemical Biased unbiased [Cu(NH3)2]+ mobility show aluminum pairing in eight-membered rings accelerates local hopping, demonstrate increased NH3 concentration enhances long-range diffusion. The probability finding two complexes same cage - key SCR-NOx reaction increases with Cu content Al content, does correlate Cu+. Supporting experimental evidence was obtained from reactivity tests Cu-CHA catalysts controlled composition.