Researchers have developed a gold-based catalyst that achieves high yields of acetaldehyde from bioethanol at lower temperatures than previous benchmarks. The innovation, involving a mix of gold, manganese, and copper, outperforms a decade-old record while promoting sustainability. This advance could make production of key industrial chemicals more environmentally friendly.
Acetaldehyde serves as a vital building block in manufacturing, particularly for plastics and pharmaceuticals. Traditionally, it is produced via the ethylene-based Wacker oxidation process, which is costly and environmentally burdensome. A greener approach involves selective oxidation of bioethanol, though past catalysts struggled to balance activity and selectivity, often yielding less than 90% acetaldehyde.
Over a decade ago, scientists including Peng Liu and Emiel J.M. Hensen introduced an Au/MgCuCr2O4 catalyst that reached over 95% yields at 250°C and maintained stability for more than 500 hours. This milestone, detailed in studies from 2013 to 2017, highlighted a key Au0-Cu+ interaction but left challenges in creating non-toxic versions that operate at even lower temperatures.
In recent work, a team led by Prof. Peng Liu of Huazhong University of Science and Technology and Prof. Emiel J.M. Hensen of Eindhoven University of Technology advanced this field. They engineered Au/LaMnCuO3 perovskite catalysts, varying manganese-to-copper ratios through a sol-gel combustion process followed by gold nanoparticle coating. The optimal variant, Au/LaMn0.75Cu0.25O3, delivered a 95% acetaldehyde yield at 225°C and stayed stable for 80 hours.
Higher copper concentrations reduced performance, as copper lost its active state during reactions. Computational analyses using density functional theory and microkinetic modeling revealed that copper doping in the LaMnO3 structure creates active sites near gold particles. These sites facilitate oxygen and ethanol interactions, lowering energy barriers for the reaction.
The findings, published in the Chinese Journal of Catalysis (2025, volume 75, pages 34), underscore the value of precise composition tuning for efficiency and stability in sustainable chemical production. Materials were provided by the Dalian Institute of Chemical Physics, Chinese Academy of Sciences.
