Metal–Organic Framework-Derived Ni–S/C Catalysts for Selective Alkyne Hydrogenation

Abstract

A carbon matrix-supported Ni catalyst with surface/subsurface S species is prepared using a sacrificial metal–organic framework synthesis strategy. The resulting highly dispersed Ni–S/C catalyst contains surface discontinuous and electron-deficient Ni δ+ sites modified by p-block S elements. This catalyst proved to be extremely active and selective for alkyne hydrogenation. Specifically, high intrinsic activity (TOF = 0.0351 s –1 ) and superior selectivity (>90%) at complete conversion were achieved, whereas an analogous S-free sample prepared by the same synthetic route performed poorly. That is, the incorporation of S in Ni particles and the carbon matrix exerts a remarkable positive effect on catalytic behavior for alkyne hydrogenation, breaking the activity–selectivity trade-off. Through comprehensive experimental studies, enhanced performance of Ni–S/C was ascribed to the presence of discontinuous Ni ensembles, which promote desorption of weakly π-bonded ethylene and an optimized electronic structure modified via obvious p–d orbital hybridization.