Oxygen vacancies promoted catalytic hydrodefluorination over Pd/La2O3 catalyst for the efficient degradation of fluorophenols at mild condition

The efficient hydrodefluorination at mild conditions is a huge challenge during catalytic hydrodefluorination for the treatment of wastewater containing fluorophenols. The application of lanthanum oxide as the catalyst support for the Pd-catalyzed hydrodefluorination of fluorophenols was proposed. It was found that the Pd/La2O3 catalyst exhibited a much higher HDF activity than other catalysts. Further investigation of the reaction kinetic and mechanism revealed that the oxygen vacancy promoting mechanism was dominant during HDF of 4-fluorophenol over Pd/La2O3 catalyst. The 0.2 wt% Pd/La2O3 catalyst with rich oxygen vacancies has a high HDF activity, fully degrading the 4-fluorophenol within 120 min at mild condition. The calculated TOF of this catalyst (0.34293 min-1) is more than 70 times that of 1 wt% Pd/SiO2 catalyst, making it to be a promising candidate for the hydrodefluorination of fluorophenols.