Tuning Surface Carbon Affinity and Olefin Activation in Intermetallic Alloys for the Semi-Hydrogenation of Acetylene to Ethylene

Understanding and developing inexpensive materials that exhibit appropriately tunable surface chemical reactivity towards carbon and unsaturated hydrocarbons is critical in many olefin production and functionalization reactions. Intermetallic alloys -- transition metals mixed with larger p-block elements -- present a special class of materials that exhibit highly tunable surface chemistry as well as improved stability. This study focuses on understanding how the size of the p-block element affects orbital overlap, the strength of bulk bonding, and the residual surface reactivity towards carbon-carbon double bonds. A combined experimental and theoretical investigation of NiB, NiAl, NiGa, NiIn, and NiTl materials in the semi-hydrogenation of acetylene to ethylene has been performed. Clear correlations between orbital overlap, surface reactivity towards ethylene, and catalytic performance were discovered. Further study of the NiAl system with respect to element ratio in the solid revealed that additional tunability of these materials is readily achieved.