Article ID Journal Published Year Pages File Type
60975 Journal of Catalysis 2014 10 Pages PDF
Abstract

•Intermetallic Ni–Zn catalysts were employed for acetylene semi-hydrogenation.•Isotopic labeling was used to evaluate reaction pathways.•Ethylene selectivity increases with increasing zinc content.•Zinc addition to nickel reduces the propensity for carbon–carbon bond formation.

Isotopic labeling and density functional theory (DFT) were used to determine the mechanism for acetylene hydrogenation and oligomerization on well-defined intermetallic nickel–zinc catalysts. The primary benefit of adding zinc to nickel is a reduction in oligomeric species formation which leads to higher ethylene selectivity. The production of ethane is not highly dependent on zinc content; therefore, ethane production is not a good descriptor of ethylene selectivity since acetylene may also be converted to higher molecular weight products. Analysis using DFT and Langmuir–Hinshelwood kinetics shows that the large decrease in the adsorption energy of acetylene on intermetallic NiZn compared to pure Ni is responsible for the observed increase in ethylene selectivity. The adsorption energy of acetylene appears to be a descriptor for carbon–carbon bond formation since a high adsorption energy leads to an increased coverage of C2 species and an increased rate of carbon–carbon bond formation.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (99 K)Download as PowerPoint slide

Related Topics
Physical Sciences and Engineering Chemical Engineering Catalysis
Authors
, , , , , , ,