Study on the Electrochemical Oxidation Desulfurization Behavior of Model Diesel on Anodic Alumina Oxide and Ceria Nanotubes

摘要

Anodic alumina oxide and ceria (AAO-CeO2) nanotubes have been used as an anode catalyst to remove sulfur from the model diesel composed of 1000 ppm of benzothiophene (BT), 600 ppm of dibenzothiophene (DBT), and 300 ppm of 4,6-dimethyldibenzothiophene (DMDBT). During the desulfurization process, BT can be removed by two main routes, i.e., oxidized to sulfone (BTO2) and sulfates (SO42-), while for DBT and DMDBT, the main removal way is only to be oxidized to sulfates. The desulfurization efficiencies of 1000 ppm of BT, 600 ppm of DBT, and 300 ppm of DMDBT as individuals are 98.07, 96.82, and 92.65%, which are much higher than their respective desulfurization efficiency in the model diesel (mixture of BT, DBT, and DMDBT). Density functional theory (DFT) calculations and cyclic voltammetry (CV) are further used to study the electrochemical oxidation desulfurization behavior of the three sulfides, and the results show that there may exist a critical point for the sulfur concentration; when the concentration is lower than the point, the desulfurization efficiency increases with increasing the sulfur concentration, whereas when the concentration is higher than the point, the desulfurization efficiency shows an opposite trend.