Bimetallic Ni–Zn/TiO2 catalysts for selective hydrogenation of alkyne and alkadiene impurities from alkenes stream

This study investigates the alternative of replacing noble metals by base as catalysts for selective hydrogenation polyunsaturated hydrocarbons. Nickel are active this type reaction, but poorly selective. However, former calculations anticipated that Ni–Zn alloys could have higher selectivity to alkenes than monometallic Ni depending on Ni/Zn atomic ratio in alloy. In contribution, alloy nanoparticles supported TiO2 synthesized acetylene and butadiene. The designed with 0.5 wt% loading various nominal ratios prepared deposition–precipitation urea (DPU). STEM-HAADF imaging coupled EDS analysis reveals bimetallic particles formed after reduction treatment at 450 °C. Alloying Zn leads a slight increase average particle size broadening distribution compared Ni. measured is always one, which be due evaporation under beam. results show although catalytic activity slightly reduced alloying Zn, ethylene enhanced from 50% up 85%, expense formation oligomers (coupling products). suffer progressive deactivation reaction. During butadiene performed presence an excess propene, Ni–Zn/TiO2 significantly more stable, high constant butenes (> 95%), Ni/TiO2, deactivates rapidly first hours. Some hypotheses concerning observed differences stability discussed.