Hollow Nitrogen- or Boron-Doped Carbon Submicrospheres with a Porous Shell: Preparation and Application as Supports for Hydrodechlorination Catalysts

Nitrogen- or boron-doped carbon submicrospheres with a hollow core and a porous shell were prepared via a template method and tested as supports for Pd/C catalysts. The carbon precursor was a phenol-formaldehyde resin that was generated into a silica template using pyridine, 1,10-phenantroline, and sodium tetraphenylborate as doping agents. The nitrogen and boron atomic percentages in doped carbon reached 0.5–3.6 and 0.03–0.67, respectively. High specific areas of up to 1846 m2/g with an important contribution of mesopores were achieved. The prepared Pd catalysts (1% w) exhibited unique features due to the morphology, porous structure, and doping of the support. The active phase was well-dispersed as nanoparticles with narrow size distribution (<10 nm) in an outer shell with a thickness of 77–124 nm. The short diffusion path needed for reactants and the well-developed network of mesopores of the shell contributed to diminish mass-transfer constraints. The catalysts showed remarkable activity (50–76 mmol/g...