Ternary mixed-oxide synergy effects of nano TiO2-FexOy-MOk (M = Mn, Ce, Co) on α-pinene catalytic oxidation process assisted by nonthermal plasma

Biomass fuel from plant waste is an important substitute for fossil fuels. The odorous volatile organic compounds (VOCs) is released during the drying process of biomass, which causes harm to the ecological environment and human health. The alpha-pinene is a typical odorous VOC generating during plant waste drying. Ternary nanocatalyst composed of TiO2, FexOy and MOk (M = Mn, Co, Ce) was manufactured by ultrasonic assisted hydrothermal process. The alpha-pinene catalytic oxidation property of ternary nanocatalysts were investigate in a dielectric barrier discharge reactor assisted by nonthermal plasma. The pore structure parameters of ternary nanocatalysts were observed qualitatively and analyzed quantitatively by transmission electron microscopy (TEM) and N-2 adsorption test, respectively. The phase composition and active element valence of these three kinds nanocatalysts were analyzed and compared by X-ray diffraction (XRD) and X-ray Photoelectron spectroscopy (XPS). The test data showed TiO2-FexOy-CoOk ternary nanocatalyst had more complete microporous and mesoporous pore structure, better element dispersion and stronger redox performance. Meanwhile, TiO2-FexOy-CoOk sample had the best performance with alpha-pinene catalytic conversion achieving 83.3% and CO2 selectivity higher than 90% at specific energy density (SED) of 620 Jl(-1), which was almost half of the energy consumption of single non-thermal plasma catalytic reaction during the nonthermal plasma-catalyst (NTP-C) synergistic catalytic activity experiments. At the same time, the ternary nanocatalysts could obviously reduce the generation concentration of O-3 and NOx in the process of alpha-pinene catalytic oxidation. The synergy effect between TiO2, FexOy and CoOk was better than that of TiO2, FexOy and CeOk or MnOk. It could be expected as an effective method to improve the redox performance of ternary nanocatalysts by optimizing the microstructure and elemental composition, which would also be a promising way to enhance odorous VOCs catalytic oxidation efficiency and reduce the energy consumption in the NTP-C synergistic catalytic system.

Automated summary

The ternary nanocatalyst TiO2-FexOy-CoOk showed better catalytic oxidation properties, achieving high conversion efficiency of alpha-pinene and CO2 selectivity. The synergy effect between TiO2, FexOy and CoOk was stronger than other combinations, indicating a potential method to enhance odorous VOCs catalytic oxidation efficiency and reduce energy consumption.