Plasma Synthesis Of Lamellar Material Supported Nano-palladium Catalyst And Performance Research

Nitrophenol is one of the most common pollutants in aqueous system.It is urgent to develop efficient catalysts for nitrophenol reduction.Nanopalladium catalyst is one of the most commonly used catalyst for catalytic reduction of nitrophenol.In this paper,a series of supported nanopalladium catalysts were synthesized by nitrogen glow discharge plasma reduction using MoS₂,graphene oxide and Mg-Al LDHs as carriers.The structure,morphology and surface composition of the catalysts were characterized by XRD,TEM,FT-IR,Raman,XPS etc.The synthesized catalysts were used to catalyze the reduction of4-nitrophenol.MoS₂ supported nano Pd catalysts（Pd/MoS₂）were synthesized via by N₂ glow discharge plasma.The effect of plasma reduction time was investigated.MoS₂ was doped successfully by nitrogen plasma.The conversion frequency of nitrophenol reduction was56.4 h^-1 over Pd/MoS₂ with Pd loading amount of 1%when the plasma treatment time of 60 min,which was 5 times higher than that of commercial Pd/C catalyst.Layered double hydroxide（LDHs）supported nano Pd catalyst（Pd/LDHs）was synthesized using Mg-Al-LDHs as carrier by N₂ glow discharge plasma.The effects of plasma reduction time and Pd loading amount were investigated.With the increase of plasma treatment time,LDHs layers were gradually exfoliated,destroyed and broken,and the reduction degree of Pd（Ⅱ）was increased.In addition,N₂ plasma caused N doping of LDHs,which enhanced the catalytic properites of 4-nitrophenol reduction reaction.With the decrease of Pd loading amount,the dispersion of Pd NPs on the surface of LDHs improved,and the catalytic properties of nitrophenol reduction increased.The conversion frequency of 4-nitrophenol reduction reaction（TOF）is 205.4 h^-l over Pd/LDHs with Pd loading amount of 1%under the plasma treatment time of 60 min,which is 20times higher than that of commercial Pd/C catalyst.Partially reduced nitrogen-doped graphene oxide supported Pd nano particles（Pd/PNGO）were synthesized by N₂ glow discharge plasma.With the increase of plasma treating time,GO is partially reduced and nitrogen-doped simultaneously,and the reduction degree of Pd（Ⅱ）is increased,which enhanced the catalytic properties of nitrophenol reduction reaction.With the decrease of Pd loading,the dispersion of Pd NPs on the surface of nitrogen-doped graphene oxide increased,and the catalytic properties of 4-nitrophenol reduction improved.The conversion frequency of 4-nitrophenol reduction reaction（TOF）is 366.9 h^-1 over Pd/PNGO with Pd loading amount of 1%under the plasma treatment time of90min,which is 35 times higher than that of commercial Pd/C catalyst.