Unveiling the effect of gas treatment on the electronic structure of carbon nanotube-supported Pd catalysts for electroreduction of H2O2 and Heck reaction.

This study explored the impact of gas treatments on the structures of multi-walled carbon nanotubes supported Pd (CNT-Pd) catalysts used for electrocatalytic H2O2 reduction and the Heck cross-coupling reaction. The CNT-Pd catalyst was prepared by anchoring Pd nanoparticles on thiolated CNTs. XPS was conducted to examine the surface composition and electronic structure changes of the CNT-Pd catalyst before and after gas treatment. The XPS results revealed that as-prepared CNT-Pd contains at least two different oxidation states on the surface, whereon their proportions depend on the gas used for treatment. Treatment with H2 leads to Pd(0) enrichment near the surface, while O2 treatment causes Pd(Ⅱ) enrichment of CNT-Pd. All catalysts containing both Pd(0) and Pd(Ⅱ) were active toward H2O2 reduction, and the Heck cross-coupling reaction of n-butyl acrylate and 4-iodotoluene; increased proportion of metallic Pd(0) boosted the catalytic reaction. However, the catalyst stability increased as the amount of Pd(II) increased.

The scope and limitation of nickel-catalyzed aminocarbonylation of aryl bromides from formamide derivatives.

Nickel-catalyzed aminocarbonylation of aryl halides is described. A well-defined air-stable nickel-phosphite catalytic system (Ni(OAc)(2).4H(2)O/phosphite 1) effectively promoted the aminocarbonylation of aryl bromides with a range of formamides to give the corresponding aryl amide products in moderate to good yields. The less hindered formamide required lower catalytic loading for full conversion and produced higher yields than the more hindered one. It also exhibited base-dependent activity toward formamides.