Ti–N ligand‐directed tunable TiO 4 / TiO 6 active sites in TS ‐1 for enhanced olefin epoxidation performance

Abstract Precise construction of titanium active sites, in particular synergistic TiO 4 and TiO 6 sites within the titanium silicalite‐1 (TS‐1) framework is a fundamental challenge in zeolite catalysis. Herein, we develop a Ti–N ligand‐directed strategy to regulate the condensation pathways of Ti species. By in situ coordinating Ti species with N atoms in amino acids, the formed Ti–N ligands suppressed self‐condensation of Ti(OH) 4 , directing the formation of TiO 4 /TiO 6 synergistic active sites. Through characterizations and DFT calculation, we demonstrate that the acid dissociation constant of amino acids governs the strength of Ti–N ligands and thus suppresses the self‐condensation of Ti(OH) 4 , thereby modulating Ti coordination environment. Consequently, the TS‐1 with optimized TiO 4 /TiO 6 synergistic active sites exhibits exceptional performance in the epoxidation of 1‐butene, achieving 99.5% selectivity toward 1,2‐epoxybutane with a 99.0% hydrogen peroxide utilization efficiency. This work paves a ligand‐assisted strategy in the rational design of active sites in TS‐1 catalysts at the molecular level.