Ni and Zn doping effect on Cu/SiO2 in nonoxidative ethanol dehydrogenation

Non-oxidative ethanol dehydrogenation opens a road for sustainable production of acetaldehyde and butadiene. One crucial part of producing butadiene by the Lebedev process is high-temperature stability of ethanol-to-acetaldehyde conversion. However, copper-based catalysts, despite exhibiting high activity and selectivity, suffer from sintering and coking and need to be improved for successful industrial application. Herein, we show Cu-based (~2.5 wt%) catalysts doped by Ni and Zn (0.02−0.3 wt%) to improve the catalytic performance of nanoparticles. Catalysts were prepared by hydrolytic sol-gel and dry impregnation. STEM analysis determined nanoparticle sizes in the 1.9−2.8 nm range. Ni-doped catalysts outperformed parent Cu catalysts in ethanol dehydrogenation activity at lower temperatures (185-220 °C) but suffered from faster deactivation. Zn-doped catalysts exhibited an improved high-temperature stability. For these materials, acetaldehyde selectivity fluctuated around ~90 % and acetaldehyde productivity reached 3.63 g · g−1 · h−1 at 290 °C. The improved stability of Zn-doped samples correlated with a lower coke formation (TG analysis).