Synthesis Of Pd/Au Bimetallic Nanoparticle-loaded Ultrathin Graphitic Carbon Nitride Nanosheets And Catalytic Application

Noble metal nanoparticles(NPs)applied in heterogeneous catalysis have attracted considerable attention due to their highly efficient catalytic performance.Some bimetallic NPs,owing to their distinctive physicochemical properties,better catalytic performance than either of the constituent materials,have attracted the great attentions.However,in the practical application,free noble metal NPs can easily aggregate,leading to a considerable loss in catalytic activity.To solve this problem,a large number of supporting materials have been used as substrates to support and stabilize NPs.In this paper,Pd/Au bimetallic NPs were successfully decorated on the ultrathin graphitic carbon nitride nanosheets(g-C3N4-N)by a facile one-pot deposition reduction method.The obtained materials were characterized via scanning electron microscope(SEM),transmission electron microscopy(TEM),high-resolution TEM,energy-dispersive X-ray spectroscopy,X-ray powder diffraction and X-ray photoelectron spectroscopy(XPS).The catalytic performance of the nanohybrid was assessed by the reduction reaction of 4-nitrophenol(4-NP)to 4-aminophenol(4-AP),meanwhile,the as-synthesized material was accessed by the experiment of anti-oxidation and recyclability.The main results obtained are as follows:(1)This work demonstrated that the kind of special 2D ultrathin sheet-like material is a good functional materials.The obtained results showed that Pd/Au bimetallic NPs with average diameter around 8 nm are homogeneously dispersed on the surface of unmodified g-C3N4-N.Moreover,the alloy structure of Pd/Au bimetallic NPs was confirmed.Through the analysis of XPS results,we can make reasonable speculation that electron transfer could take place not only between Pd/Au bimetallic NPs and g-C3N4-N,but also between Au and Pd NPs.(2)The catalytic reduction of p-NP in the presence of excess NaBH4 to generate p-aminophenol(p-AP)was selected as a model reaction to assess the catalytic properties of Pd/Au@g-C3N4-N,the obtained results showed that the catalytic performance is ascribed to the structure and constitution of Pd/Au bimetallic material.Pd/Au@g-C3N4-N(1:1)shows the highest catalytic activity than other all as-obtained catalysts in this study through the evaluation of the apparent rate constant,and the reaction could be evaluated by pseudo-first-order kinetics.Pd/Au@g-C3N4-N(1:1)can achieve a large apparent rate constants k of 0.7907 min-1 for the p-NP reduction,which was better than either of pure Pd or Au nano hybrids.Moreover,the as-synthesized material has excellent anti-oxidation and recyclability,which greatly promotes its industrial application.