Impacts of Nano-Sized Co3O4 on Ignition and Oxidation Performance of N-Decane and N-Decane/1,2,4-Trimethylbenzene Mixtures

Nano-sized Co3O4 is an effective catalyst for fuel oxidation due to its high capacity of oxygen storage, and it is thus frequently applied in improving the oxidation performance of hydrocarbon fuels. In our present work, attempts were made to study the catalytic performance of Co3O4 for the oxidation of liquid fuels over a wide temperature range. Neat n-decane and n-decane/1,2,4-trimethylbenzene mixtures were chosen because they are typical liquid hydrocarbon fuels. The evidences from this study suggest that the temperatures of both fuel ignition and full conversion are significantly decreased by Co3O4 catalyst. CO2 is the only product detected in the catalytic oxidation, which also proves the complete oxidation of the liquid fuels. Furthermore, to explore the possible reaction pathways on the catalyst surface, temperature-dependent and time-dependent in situ DRIFTS were employed to identify surface species and analyze catalytic mechanism. Various surface intermediates including bidentate, monodentate carbonate species, carboxylate species and molecular adsorbed n-decane have been observed. The experimental results indicate that n-decane oxidation over Co3O4 proceeds via the Mars-van Krevelen mechanism where lattice oxygen plays a critical role in the fuel oxidation.