Coordinatively Unsaturated Al3+ Sites Anchored Subnanometric Ruthenium Catalyst for Hydrogenation of Aromatics

Single metal atoms and metal clusters have attracted much attention because of their high dispersity, special electronic structures, and uniformity of active sites as heterogeneous catalysts, but it is still challenging to generate stable single atoms and clusters with high metal loadings. Supports play a crucial role in determining particle morphology and maintaining dispersion. Herein we synthesize an amorphous alumina with 29% coordinatively unsaturated pentacoordinate Al3+ (Al-penta(3+)) sites, which can anchor atomically dispersed Ru species with 1 wt % loading. Strong interactions between Ru and Al-penta(3+) centers were detected, resulting in distinct Ru geometric and electronic features. When used in benzene hydrogenation reaction, fairly high specific activity (TOF = 5180 h(-1)) were obtained. The high catalytic performance is considered closely correlated with the high utilization of special Ru active sites.