Mechanism on the plasma-catalytic oxidation of graphitic carbon over Au/γ-Al2O3 by in situ plasma DRIFTS-mass spectrometer.

ABSTRACT

Plasma-catalytic oxidation of particulate matter (PM) has potential applications for diesel exhaust cleaning. There is a grand requirement to explore the mechanism of carbonaceous PM oxidation for the development of plasma catalysts. Herein, Au/γ-Al2O3 was used to catalyze the gasification of the graphitic carbon. A modified diffuse reflectance infrared Fourier transform spectrometer equipped with a mass spectrometer was originally utilized to in situ characterize the surface intermediates of graphite on Au/γ-Al2O3 and the gaseous products during the discharges processes in the O2-He balanced gases. It was found that O atoms and O3 play important roles in the formation of surface oxygen complexes (SOCs) and facilitate the gasification of SOCs to CO2 in the presence of Au/γ-Al2O3. The findings are helpful to understand the plasma-catalytic oxidation mechanism of PM and further develop efficient plasma catalysts.