Subsurface Carbon as a Selectivity Promotor to Enhance Catalytic Performance in Acetylene Semihydrogenation

Abstract

For supported metal catalysts, subsurface sites can significantly influence the adsorption and reaction behaviors on surface sites via the electronic effect and geometric effect. Subsurface carbon in PdCx has been proven to be an effective selectivity promoter in acetylene semihydrogenation. Herein, we theoretically calculated the reaction trajectory on Ni3ZnC0.7 and designed a metal–organic framework-layered hydroxide salt-derived synthesis strategy for the Ni3ZnC0.7/C catalyst. The formation of the flake-like Ni3ZnC0.7 phase was monitored by in situ X-ray diffraction (XRD) and confirmed by XRD, transmission electron microscopy, and selected area electron diffraction characterizations. In acetylene semihydrogenation, the Ni3ZnC0.7/C catalyst had 85% ethylene selectivity even at 100% acetylene conversion, supporting the conclusions from density functional theory calculations. The green oil selectivity was controlled below 2%. All results indicated that incorporating carbon atoms in the subsurface sites significantly enhanced the ethylene selectivity in acetylene semihydrogenation.