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

Cristina Ruiz-García, Francisco Heras, Noelia Alonso-Morales, Luisa Calvo, Juan J Rodriguez, Miguel A Gilarranz

Index: 10.1039/C8CY00384J

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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% N, w) and non-doped mesoporous carbon materials with equivalent pore structure were prepared via templating with MSU-F silica. At 30 °C the doping of the support resulted in a higher catalytic activity (26 vs 49 mmol g-1 Pd min-1 for non-doped and doped support, respectively) in the removal of 4-chlorophenol from water. However, the activity of the catalyst with non-doped carbon increased more with reaction temperature, being even the most active at 70 °C (131 vs 102 mmol g-1Pd min-1 for non-doped and doped support, 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 at mild temperature conditions, whereas non-doped supports are more convenient for the intensification of the process by increasing the reaction temperature.