Ni active sites isolated by antimony toward enhanced propyne semi‐hydrogenation

Abstract

Regulating Ni active sites toward the formation of target product is of great importance for designing high‐performance cost‐effective catalysts for catalytic semi‐hydrogenations but remains challenging. Herein, we report the fabrication of NiSb intermetallic catalyst via structural transformation from a layered double hydroxides precursor for boosting propyne semi‐hydrogenation. Systematic characterizations, including x‐ray diffraction, atomic‐resolution electron microscopy, and x‐ray absorption spectroscopy, provide evidence for the formation of P63/mmc NiSb intermetallic phase in the synthesized NiSb catalyst. The host Ni active sites are demonstrated to be isolated by the high‐electronegativity p‐block guest Sb sites, which deliver remarkably high selectivity to target propene, that is, up to propene selectivity of 96% at nearly full propyne conversion. Temperature‐programmed surface reaction and temperature‐programmed desorption measurements combined with theoretical calculations unravel that the excellent selectivity originates from kinetically more favorable desorption of propene than its hydrogenation to propane on the regulated Ni active sites.

Carburization in the Crystalline Structure of the Metal Ag for Efficient Selective Hydrogenation of Acetylene

“…Among the promising alternative catalysts (Ni, − Cu, − Au, − and CeO 2 − ), metal Ni-based catalysts with incomplete d-electron orbitals have been frequently employed to replace Pd-based catalysts in selective hydrogenation, owing to the high hydrogen dissociation ability . But the Ni catalysts always suffer from overhydrogenation to ethane and acetylene coupling to oligomers, leading to low ethylene selectivity and low stability.…”