Single-Atom Ni-Modified Al2O3-Supported Pd for Mild-Temperature Semi-hydrogenation of Alkynes

It is challenging to develop an alkyne semi-hydrogenation catalyst with both high selectivity and high activity, especially at low temperatures and low pressures. Herein, a single-atom Ni-modified Al2O3-supported Pd is proposed as a modulation strategy to optimize the selectivity of alkyne semi-hydrogenation. Sphere-difference-corrected transmission electron microscopy and synchrotron radiation confirm that Ni single atoms enter the alumina lattice in a highly dispersed state, while Pd is loaded on the Ni-modified support in the form of nanoparticles. For the semi-hydrogenation of phenylacetylene, the Pd0.5/Ni0.5@γ-Al2O3 catalyst with Pd and Ni loadings of 0.45 and 0.43 wt %, respectively, achieves 98% conversion and 94% selectivity at 298 K and 0.1 MPa. It also possesses good stability, as the activity remains unchanged after 10 cycles of application. The Pd0.5/Ni0.5@γ-Al2O3 catalyst inherits the high activity of Pd and the high selectivity of Ni to achieve efficient semi-hydrogenation of phenylacetylene at low temperatures and pressures, benefiting from the synergistic effect of Pd and Ni.