Assessing Self-Interaction Corrections in the Selective Catalytic Reduction of NO on a Cu-SSZ-13 Zeolite Cluster Model.

Self-interaction error (SIE) in density functional theory (DFT) calculations can lead to inaccurate descriptions of catalytic processes. In this work, we investigate the effects of SIE on a catalytic NO activation cycle on a cluster model of the Cu-SSZ-13 zeolite, systematically identifying transition states and reaction pathways for both single- and multistep reactions. We assess SIE using the Perdew-Zunger self-interaction correction (PZSIC) method, implemented with the Fermi-Löwdin orbital SIC (FLOSIC) approach. We benchmark the performance of standard DFT functionals (LDA, PBE, and r2SCAN) and SI-corrected functionals (PZSIC-LDA and the locally scaled LSIC(zσ)-LDA) against CCSD(T) reference energies for both adsorption energies and reaction barriers. The standard functionals increase in accuracy in the order LDA < PBE < r2SCAN, but all three tend to overestimate adsorption energies and underestimate reaction barriers. While PZSIC-LDA improves the description of reaction energetics over LDA for several reaction steps, it introduces large errors for processes that involve a change in the Cu-oxidation state. These errors are linked to the spurious destabilization of a filled 3d10 electronic shell relative to 3d9 in PZSIC calculations as described recently by Maniar et al. (Proc. Nat. Acad. Sci. 122, e2418305122 (2025)). This causes 3d9-like electronic configurations for the Cu active site to be favored over reference 3d10 configurations at several points in the NO reaction cycle, giving rise to self-consistent PZSIC densities that are qualitatively incorrect. By locally scaling the SIC, LSIC mitigates some of the PZSIC errors and gives more consistent results than PZSIC-LDA. We conclude that to obtain accurate descriptions of catalytic reactions with SIC-based methods, the spurious energetics of transition metal complexes in competing oxidation states must be eliminated.