Rational Control on the Selectivity of Ru Catalyst for Hydrogenation of 4-Nitrostyrene via Strain Regulation

Tuning the selectivity of metal catalysts is of paramount importance, yet a great challenge. Here, a new strategy to effectively control the selectivity of metal catalysts, by tuning the lattice strain, is reported. In this approach, we introduce a certain amount of Co atoms into Ru catalysts to compress the Ru lattice, as confirmed by aberration corrected high-resolution transmission electron microscopy (HRTEM) and X-ray absorption fine structure (XAFS) measurements. We discover that, the lattice strain of Ru catalysts can greatly affect their selectivity and Ru with 3% lattice compression exhibits extremely high catalytic selectivity for hydrogenation of 4-nitrostyrene to 4-aminostyrene compared to pristine Ru (99% Vs. 66%). The theoretical studies prove that the optimized lateral compressive strain facilitates hydrogenation of nitro-group but impedes the hydrogenation of vinyl-group. This study provides a new guideline for designing metal catalysts with high selectivity.