Tuning of the Bimetallic CoNi Electronic Structure for Inducing Catalytic Activity and Selectivity for Styrene Hydrogenation

Abstract

Tuning the selectivity of catalytic hydrogenation is of vital importance and is challenging in the chemical industry. The present study demonstrates that the highly selective hydrogenation of styrene can be precisely controlled by simply tuning the reaction temperature over Co_xNi_y (x + y = 1) bimetallic nanocatalysts supported on SiO₂. The Co_0.5Ni_0.5 catalyst exhibits markedly enhanced catalytic activity, with a styrene conversion that is over 4 times higher than that of the pure Ni catalyst and 18 times higher than that of the pure Co catalyst during the initial 1 h. This outstanding catalytic performance is comparable to that of Ru and Pd catalysts, and its selectivity is even more advanced than those of some state-of-the-art noble metals. DFT calculations show that the catalytic performance of the bimetallic CoNi catalyst is improved due to the optimized electronic structure of the CoNi alloy. These results suggest that nanosized bimetallic CoNi could be a promising catalyst for the highly selective hydrogenation of C═C double bonds in unsaturated organic compounds at different positions. Our findings offer useful insights for the design of noble metal-free bimetallic nanocatalysts for highly tunable selective hydrogenation reactions.