Synthesis of modified carbon nanotube-supported Pd and the catalytic performance for hydrodehalogenation of aryl halides

The effects of surface functionalization on the deposition of Pd nanoparticles on multi-walled carbon nanotubes (CNTs) have been studied. Two methods were used for the functionalization of CNTs: one employed a 1:1 (v/v) mixture of concentrated H₂SO₄/HNO₃, sonicated at RT; the other employed a 3:1 (v/v) mixture of concentrated H₂SO₄/HNO₃, sonicated at 60 ^oC. A large number of surface oxide groups were introduced on the surface of functionalized CNTs, especially in strong oxidation power (H₂SO₄/HNO₃ = 3:1, 60 ^oC). The dispersion of Pd nanoparticles on CNTs was found to depend on the amount of surface oxide groups, with larger amounts of surface oxide groups resulting in higher dispersion of Pd nanoparticles. The effects of CNT surface functionalization on the performance of Pd/CNTs catalysts were studied, and the reaction conditions optimized, using the hydrodebromination of bromobenzene as model reaction. Under optimal conditions, the hydrodehalogenation of various aryl halides were tested over Pd/CNTs catalysts. (author)