Synergistic catalysis of acidity, redox properties, and diffusion limitation in Ru-based zeolites for efficiently catalytic combustion of o-dichlorobenzene.

A series of Ru-based zeolites with distinct topological structures was synthesized for the catalytic oxidation of o-dichlorobenzene (o-DCB). This study proposes a design strategy on pore construction engineering for high-performance catalysts to remove chlorinated aromatics. The key novelty lies in elucidating the prerequisite role of pore architecture and establishing structure-performance correlations. Among the tested catalysts, Ru/Beta demonstrated an outstanding performance: achieving complete conversion of o-DCB, 100 % CO2 yield, and 98.5 % HCl yield at 400 °C, along with excellent stability. Pore structure was identified as the primary determining factor of catalytic behavior. Calculations of kinetic diameter and simulations of molecular dynamic jointly confirmed that 12-membered rings (MR) and mesoporous systems enable the free diffusion of o-DCB, while 8-MR cause severe mass transfer limitations, fundamentally constraining activity. Furthermore, a higher dimensionality of the pore channels enhances the utilization efficiency of active sites, thereby boosting catalytic activity. Within the porous frameworks, high specific surface area (SBET) and framework Al species were found to improve Ru dispersion, as revealed by TEM, CO-TPD, and CO-DRIFTS analyses. H2-TPR and NH3-TPD results indicate that strong redox capabilities accelerate the conversion and deep oxidation of o-DCB, while Brønsted acid sites selectively promote HCl generation. Based on these findings, a synergistic hydrolysis-oxidation mechanism is proposed, detailing the sequential reaction pathways of dechlorination, ring-opening, and deep oxidation.