(513cj) Atomically Precise Design of Heterogeneous Catalysts for Enhanced Pairwise Selective Addition of Parahydrogen to Unsaturated Hydrocarbons

Well-defined shapes are superior in catalysis studies as they enable investigations on catalytic activities down to surface facet level. Here, a modified atomic layer deposition technique was developed to achieve ultra-low loadings (8-16 ppm) of platinum on shaped ceria nanocrystals. By using octahedra and cubes, which expose exclusively (111) and (100) surface facets respectively, the effect of CeO₂ surface on the stability of isolated Pt atoms was investigated. A Pt/CeO₂(111) catalyst with only 8 ppm of Pt exhibited an unprecedented high pairwise selectivity for continuous-flow hydrogenation (6.1 %), which is a factor of two higher than the best previously reported value for a monometallic heterogeneous Pt catalyst. Strong interaction between Pt and the CeO₂ (111) is found to increase the stability of atomically dispersed Pt under reducing conditions and affords significantly higher NMR signal enhancement than CeO₂ (100).