N-Doped CMK-3 carbons supporting palladium nanoparticles as catalysts for hydrodechlorination

The effect of nitrogen doping of a carbon support on the activity of Pd catalysts in the hydrodechlorination of 4-chlorophenol in water has been studied. Highly mesoporous CMK-3 carbons have been synthesized by infiltration of a commercial resol resin into SBA-15 silica followed by pyrolysis at 700 °C and removal of the template with NaOH. Nitrogen doping was achieved by infiltrating 1,10-phenantroline together with the resin. Equivalent porous texture and Pd nanoparticles size were obtained for the catalysts based on undoped and nitrogen-doped CMK-3 carbons. The catalysts allowed fast 4-chlorophenol hydrodechlorination with exclusive selectivity to phenol. A higher activity was observed at 30 °C for the catalyst with the N-doped support (76-81 mmol·gPd-1·min-1), showing the beneficial effect of nitrogen doping of the carbon supports. The different behavior was also evidenced by the activation energies calculated for the catalysts with undoped (53 kJ·mol-1) and N-doped CMK-3 carbon (36 kJ·mol-1) in the 30 - 70 °C temperature range
The authors thank Hexion Speciality Chemicals Iberica S.A. for providing the resol resin Bakelite PF9934 FL and MINECO for providing financial support (CTQ2012-32821, CTQ2015-65491_R) and for the Ph.D. (BES-2013-066085) grant to C.R.-G