Structure sensitivity of propene oxidation over Co-Mn spinels

作者：Tian Zhen Yu^*; Bahlawane Naoufal; Vannier Vincent; Kohse Hoeinghaus Katharina

来源：Proceedings of the Combustion Institute, 2013, 34(2): 2261-2268.

DOI：10.1016/j.proci.2012.06.182

• Catalytic oxidation
• Cobalt manganese oxide
• Chemical vapor deposition
• VOC
• Thermal stability

Single-phase cobalt-manganese spinel oxides (Co3-nMnnO4, CMO) were studied for the catalytic oxidation of propene in a systematic optimization strategy. CMO films were synthesized by pulsed-spray evaporation chemical vapor deposition (PSE-CVD) and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman and Ultraviolet-Visible (UV-Vis) spectroscopy. The effect of Co/Mn ratio in the mixed oxide systems on their catalytic activity was investigated in a fixed-bed reactor at T = 100-800 degrees C, with a space velocity of 90,000 mL/g(cat) h and a feed of 2% C3H6/20% O-2/78% Ar. XRD patterns, FTIR and Raman spectroscopy reveal that a cubic single-phase spinel structure is obtained for n %26lt;= 1.23, while a tetragonal spinel structure is observed for n %26gt; 1.23. With increasing of the manganese content, the temperature-programmed analysis demonstrates a lower reducibility, a general decrease of the temperature required for the reduced samples to be re-oxidized and increasing thermal stability. The catalytic tests show that the involvement of cobalt-manganese oxides in propene oxidation suppresses the formation of reaction intermediates, favoring the selectivity toward CO2 at low temperatures. Co2.35Mn0.65O4 exhibits the best catalytic performance, which follows in line with its better reducibility compared with the other compositions in the series of CMO oxides. These results show the great potential of CMO for future industrial application as a low-temperature catalytic system which does not rely on precious metals.

• 出版日期2013