Strong metal-support interactions between atomically dispersed Ru and CrO for improved durability of chlorobenzene oxidation.

In this work, two single-atom catalysts (SACs) with atomically dispersed RuO supported on CrO were successfully synthesized with a simple reduction strategy for the efficient catalytic oxidation of chlorobenzene (CB). With characterizations like Cs-corrected STEM, XPS, H-TPR, and O-TPD, the structure-activity relationship is addressed. The noble metal precursor Ru was anchored with different oxygen species and exposed facets based on the physicochemical properties of catalyst supports. Based on the analysis results, the Ru precursor could be mainly anchored into the surface lattice oxygen of CrO-M over high-index facets (223) and adsorbed oxygen of CrO-P over low-index facets (104), where the precursor Ru was all oxidized to RuO when being anchored with the oxygen species of CrO-M and CrO-P, respectively according to XPS analysis. There is a stronger metal-support interaction (SMSI) between Ru ions and the surface lattice oxygen of CrO-M, according to H-TPR and O-TPD characterizations. Further, the catalytic performance for CB combustion at a high space velocity of 120 000 mL (g h) was tested, and 1RuCrO-M performed better than 1RuCrO-P in both durability and activity. This could be attributed to the SMSI between single-atom Ru and the lattice oxygen of the 1RuCrO-M catalyst and the abundant active sites from the exposed high-index facets. The study provided a novel synthesis strategy for Ru-based SACs with SMSI effect, and the good durability of the catalyst (1RuCrO-M) extended the great potential for practical application.