Highly efficient and recyclable Ni MOF-derived N-doped magnetic mesoporous carbon-supported palladium catalysts for the hydrodechlorination of chlorophenols

Ni MOF-derived N-doped magnetic mesoporous carbon-supported Pd nanoparticles (Pd/Ni-mCN) were prepared and used in the hydrodechlorination (HDC) of chlorophenols (CPs) water pollutants with H 2 at mild reaction conditions. The Pd/Ni-mCN catalyst was characterized in detail by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N 2 adsorption/desorption, and vibrating sample magnetometry (VSM). The Pd/Ni-mCN nanocatalyst showed high activity and complete HDC conversion of a target pollutant such as 4-CP after 90   min at ambient conditions. Other CPs compounds such as 2-CP, 3-CP, 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) were also tested in the HDC reaction. 2-CP was the only intermediate product in the HDC of 2,4-DCP, with phenol being the final product. The HDC of 2,4,6-TCP proceeded with the intermediate formation of 2-CP and 2,4-DCP, this being potentially originated from the steric hindrance of the ortho-substituted Cl atom. Additionally, Pd/Ni-mCN exhibited high catalytic stability and recyclability. Thus, Pd/Ni-mCN was successfully recycled owing to its superparamagnetic properties and reused for at least five times showing stable conversions (above 99% at 90   min) the HDC of 4-CP.