The Synthesis And Characterization Of M^Cu (M=Au,Pd) Nano-composite Structure Catalysts

Precious metals were still indispensable in the process of many importantchemical production catalyst materials, but the utilization of the commercialization ofprecious metal catalysts were all less than50%.In order to solve this problem, thisstudy intended to make Cu nanoparticles as substrate to deposition scattered preciousmetals Au or Pd, the preparation of Cu nanoparticles in Au or Pd (expressed asAum^Cu or Pdm^Cu, m is the atomic ratio of Au or Pd with Cu, determination byICP-AES) nano-composite metal particles. Expect this to construct highly active newprecious metal catalysts and noble metal utilization. This paper would explore thesynthesis and characterization of M^Cu (M=Au or Pd) nano-composite structurecatalysts with different precious metals preparation.1.In the first part of this paper, It used reduction deposition and redoxreplacement method respectively to prepared the nanostructure of Aum^Cu andAum^Cu/C.This work attempted to construct Au-on-Cu nanostructured catalysts(coded as Aum^Cu, Au/Cu atomic ratio m=0.1,0.3and0.5) by reductively depositingAu with different amounts on Cu nanoparticles (Ca.3.6nm) and construct Au-on-Cunanostructured catalysts (coded as Aum^Cu, Au/Cu atomic ratio m=0.01,0.06and0.13) by redox replacement Au precursor (HAuCl4) with different amounts on Cunanoparticles(Ca.5.2nm),and the carbon carrier made Aum^Cu/C catalystnano-composite structure, and the catalytic performance of two series performance ofcatalyst were investigated by the reduction of nitro phenol and styrene epoxidationreaction. The characterization of results showed that Aum^Cu and Aum^Cu/C hadbeen successful preparation by the characterization of ICP-AES, UV-vis, TEM,XRD.Comparing the mass-specific activity of Au in samples (MSAAu), it was foundthat MSAAuwas increased with decreasing m of samples, the MSAAuon Au0.1^Cucatalyst was increased at least as10times of that on traditional pure Au catalysts inthe reduction of nitro phenol reaction. the MSAAuon Au0.01^Cu/C catalyst wasrespectively increased at least as10times and40times of that on traditional pureAu/C catalysts in the reduction of nitro phenol reaction and styrene epoxidation reaction. These results suggested that mass specific activity, i.e., the utilization of Aucatalyst can be dramatically enhanced by controllably depositing Au on Cunanoparticle to construct Aum^Cu nanostructure.2. In the second part of this paper, In the first part of this paper, we use redoxreplacement method respectively preparation Pdm^Cu/C nanostructure.This workattempted to construct Pd-on-Cu nanostructured catalysts (coded as Pdm^Cu, Pd/Cuatomic ratio m=0.4,0.7and1.0) by redox replacement Pd precursor (Na2PdCl4) withdifferent amounts on Cu nanoparticles (Ca.5.2nm),and the carbon carrier madePdm^Cu/C catalyst nanocomposite structure, and the catalytic performance of catalystwere investigated by the reduction of nitro phenol and reduction of nitrochlorobenzene reaction. The characterization of results showed that Pdm^Cu/C hadbeen successful preparation by the characterization of ICP-AES, UV-vis, TEM,XRD.Comparing the mass-specific activity of Pd in samples (MSAPd), it was foundthat MSAPdwas increased with decreasing m of samples, the MSAPdon Pd0.4^Cu/Ccatalyst was respectively increased at least as10times and3times of that ontraditional pure Pd/C catalysts in the reduction of nitro phenol reaction and reductionof nitro chlorobenzene reaction. These results suggested that mass specific activity,i.e., the utilization of Pd catalyst can be dramatically enhanced by controllablydepositing Pd on Cu nanoparticle to construct Pdm^Cu nanostructure.Attempted to construct M-on-Cu nanostructured catalysts (M^Cu,M=Au, Pd)experimental results, show that M^Cu nano composite structure can significantlyimprove the quality of the precious metal M catalyst activity than its utilization,which can be thought of scatter of precious metals from other metal nanoparticlessurface preparation for nano composite structure is expected to obtain precious metalthermal-catalysts with high utilization.