No abstract

Novel N-containing porous carbon supported Pd heterogeneous catalysts have been derived by carbonization of gelatin (GEL)/chitosan/PdCl 2 (GEL/CS/ PdCl 2 ) and GEL/polyvinyl pyrrolidone/PdCl 2 (GEL/PVP/PdCl 2 ) blends under N 2 atmosphere at 800 C. The microstructure of the resultant N-containing carbon supported Pd heterogeneous catalysts can be tailored by the nature of the blended polymers. Much larger specific surface area, better dispersion of Pd 0 /PdO nanoparticles, higher Pd and N contents are found in the case of N-containing porous carbon supported Pd heterogeneous catalysts derived from GEL/CS/PdCl 2 blend system. When the mass ratio of GEL to CS is kept at 1/1, the surface area of 644.8 m 2 /g, rich porous structure, N % of 7.2%, and Pd 0 /PdO nanoparticles sized below 3 nm are obtained in the derived Pd@N-C-GEL/CS(1/1) catalyst. It shows excellent catalytic efficiency (higher than 90%) in Heck coupling reaction of aromatic halides and alkenes, and high recycling stabilities both in aqueous (9 runs) and organic (15 runs) phase. The high activity and stability of the novel Pd@N-C-GEL/CS(1/1) catalyst have been attributed to a combination of high porous structure, strong chelation of Pd species, high thermal stability, and good solvent-resistant performances.

Nitrogen-doped mesoporous carbon-supported Pd (Pd@N-C) catalysts were prepared by pyrolyzing gelatin/templates/PdCl 2 hydrogels under N 2 atmosphere at 800 C. Using poly (ethylene glycol) block poly (propylene glycol) block poly (ethylene glycol) (P123) as soft template and/or colloidal SiO 2 as hard templates can significantly improve the Brunauer-Emmett-Teller (BET)