Synthesis of Sub-4 nm Rh-Based Intermetallic Catalyst Libraries by Sulfur-Anchoring Strategy

Atomically ordered intermetallic compounds (IMCs) have sparked continuous research interest in the catalysis owing to their unprecedented electronic and geometric features. Unfortunately, controlling the IMCs particle size into the range required for industrial catalysts remains a synthetic bottleneck, as the high-temperature annealing steps that are often necessary for the formation of intermetallic phase inevitably lead to severe metal sintering. Here, we report a general synthesis strategy for preparing a family of 10 different Rh-based IMCs with average particle sizes of <4 nm, including Rh3Ti, Rh3V, RhFe, RhGa, RhGe, Rh2Ge, RhIn, Rh3Sn2, RhSb, and Rh2Sb, based on the strong chemical interaction between metal and sulfur, which significantly suppresses the metal sintering up to 900 °C. The prepared Rh-based IMC catalysts exhibited enhanced catalytic performance for the nitroarene hydrogenation, clearly demonstrating the advantages of atomically order structure of IMCs for the chemoselective molecular recognition of nitro groups through geometric and electronic effects.