Strong metal–support interactions between atomically dispersed Ru and CrO(x) for improved durability of chlorobenzene oxidation

In this work, two single-atom catalysts (SACs) with atomically dispersed RuO(2) supported on CrO(x) were successfully synthesized with a simple reduction strategy for the efficient catalytic oxidation of chlorobenzene (CB). With characterizations like Cs-corrected STEM, XPS, H(2)-TPR, and O(2)-TPD, the structure–activity relationship is addressed. The noble metal precursor Ru(3+) was anchored with different oxygen species and exposed facets based on the physicochemical properties of catalyst supports. Based on the analysis results, the Ru(3+) precursor could be mainly anchored into the surface lattice oxygen of Cr(2)O(3)-M over high-index facets (223) and adsorbed oxygen of Cr(2)O(3)-P over low-index facets (104), where the precursor Ru(3+) was all oxidized to RuO(2) when being anchored with the oxygen species of Cr(2)O(3)-M and Cr(2)O(3)-P, respectively according to XPS analysis. There is a stronger metal–support interaction (SMSI) between Ru ions and the surface lattice oxygen of Cr(2)O(3)-M, according to H(2)-TPR and O(2)-TPD characterizations. Further, the catalytic performance for CB combustion at a high space velocity of 120 000 mL (g(−1) h(−1)) was tested, and 1RuCr(2)O(3)-M performed better than 1RuCr(2)O(3)-P in both durability and activity. This could be attributed to the SMSI between single-atom Ru and the lattice oxygen of the 1RuCr(2)O(3)-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 (1RuCr(2)O(3)-M) extended the great potential for practical application.