Breaking Trade-Off between Selectivity and Activity of Nickel-Based Hydrogenation Catalysts by Tuning Both Steric...

For selective hydrogenation of chemicals the high selectivity is always at the expense of activity and improving both selectivity and activity is challenging. Here, by chelating with p-fluorothiophenol (SPhF)-arrays, both steric and electronic effects are created to boost the performance of cheap nickel-based catalysts. Compared with dinickel phosphide, the SPhF-chelated one exhibits nearly 12 times higher activity and especially its selectivity is increased from 38.1% and 21.3% to nearly 100% in hydrogenations of 3-nitrostyrene and cinnamaldehyde. Commercial catalysts like Raney Ni chelating with SPhF-array also exhibits an enhanced selectivity from 20.5% and 23.4% to ≈100% along with doubled activity. Both experimental and density functional theory (DFT) calculation prove that the superior performance is attributed to the confined flat adsorption by ordered SPhF-arrays and downshifted d-band center of catalysts, leading to prohibited hydrogenation of the vinyl group and accelerative H₂ activation. Such a surface modification can provide an easily-realized and low-cost way to design catalysts for the selective hydrogenation.