Enhancement of the activity of Pd/C catalysts in aqueous phase hydrodechlorination through doping of carbon supports

Abstract

The enhancement of the activity of Pd catalysts for aqueous phase hydrodechlorination (HDC) was studied using N-doped tailored supports. N-Doped (1–1.7 wt% N) and non-doped mesoporous carbon materials with equivalent pore structures were prepared via templating with MSU-F silica. At 30 °C, doping of the support resulted in a higher catalytic activity (26 vs. 49 mmol g⁻¹ Pd min⁻¹ for non-doped and doped supports, respectively) in the removal of 4-chlorophenol from water. However, the activity of the catalyst with non-doped carbon supports increased more with reaction temperature, even being the most active at 70 °C (131 vs. 102 mmol g⁻¹ Pd min⁻¹ for non-doped and doped supports, respectively). The activation energy of the process was found to decrease from 32 to 16 kJ mol⁻¹ due to nitrogen doping of the support. Nitrogen doping of the carbon support is an interesting strategy to prepare catalysts with high HDC activity under mild temperature conditions, whereas non-doped supports are more convenient for the intensification of the process by increasing the reaction temperature.