Oxidative desulfurization of model diesel fuel catalyzed by carbon-supported heteropoly acids: Effect of carbon support

Keggin-type heteropoly acids (HPAs) H3PMo12O40 and H3PW12O40 supported on activated carbon were shown to be highly active catalysts for oxidative desulfurization (ODS) of model diesel fuel containing dibenzothiophene (DBT) and heptane by 30% H2O2. A number of commercial activated carbons differing in their acid-base properties were tested as the HPA support to reveal a strong effect of basicity of carbon support on the integrity of HPA structure on the carbon surface and catalyst activity. The most active catalysts, comprising decomposed H3PW12O40, outperformed best reported heterogeneous catalysts for ODS in similar systems, exhibiting 100% DBT removal from the model diesel fuel at 40-60 degrees C and H2O2/DBT = 3 mol/mol in 20-30 min with 85-88% H2O2 efficiency and could be recovered and reused without loss of activity. DRIFTS studies provided an insight into the mechanism of ODS reaction on carbon-supported HPAs.