| Transition metal phosphides, a class of materials with unique physical and chemical properties, have received much attention in the past a few years. Among the class of compounds, a number of monometallic phosphides have been a focus of recent research, because of its wide range of properties. Compared to monometal phosphides, bimetal phosphides are less reported. In the study of traditional catalysts, bimetal nanomaterials exhibit outstanding catalytic properties. Therefore, one might expect to observe a synergistic effect between two metals in bimetallic phosphides similar to the excellent catalytic performances observed in bimetallic nanomaterials. However because of the different essential attribute of different metal elements, it is difficult to prepare bimetal phosphides by one step reaction. The synthetic methods of bimetal phosphides have been limited a lot. At present, bimetal phosphides are generally synthesized by temperature-programmed reduction(TPR). However, the TPR method would cost much energy and long periods because the reaction requires high temperture and programmed reduction. In addition, it is need to add extra reducing gas like H2, which leads to the high production costs and more complex equipments. Therefore, to develop a more convenient method featuring low energy consumption for preparing bimetal phosphides is important.In this paper, two novel synthetic approaches were used to prepare bimetal phosphides NiCoP, which are the thermal decomposition of hypophosphites and metal oxide/hypophosphite precursors. Besides, the NiCoP/reduced graphene oxide(rGO) nanocomposite has been prepared by hydrothermal method, the characterizations and performances were also discussed. The main contents are summarized as follows: 1. Synthesis via thermal decomposition of hypophosphites method, characterization and adsorption performance of bimetal phosphide NiCoPBimetal phosphide NiCoP nanoparticles were successfully synthesized by thermal decomposition of hypophosphites method using nickel chloride hexahydrate(NiCl2·6H2O), cobalt chloride hexahydrate(CoCl2·6H2O) and sodium hypophosphite(NaH2PO2·H2O) as raw materials. The as-obtained products were characterized by X-ray diffraction(XRD), field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM). Furthermore, the adsorption removal property tests for some organic dyes were also investigated. The experiment results with changing single factor show that: the ratios of the materials highly affect the purity of the product. 2. Synthesis via thermal decomposition of sodium hypophosphite and metal oxide precursors, characterization and adsorption performance of bimetal phosphide NiCoPBimetal phosphide NiCoP was successfully prepared via the thermal treatment of sodium hypophosphite and precursors which was obtained from the calcination of nickel nitrate hexahydrate(Ni(NO3)2·6H2O) and cobalt nitrate hexahydrate(Co(NO3)2·6H2O) under flowing nitrogen. Compared with traditional H2-temperature-programmed reduction method, the method provides a way to produce bimetal phosphides at a relatively low temperature and without extra reducing gas H2. The as-obtained samples were characterized by XRD, FE-SEM, TEM and N2 adsorption-desorption analyses. The adsorption removel property tests of the as-prepared catalyst were also investigated. Based on the thermo gravimetric analyses(TGA) the possible growth mechanism of the bimetal phosphide NiCoP is proposed. 3. Synthesis by hydrothermal method, characterization and adsorption performance of NiCoP/rGO nanocomposites.NiCoP/r GO nanocomposites were successfully synthesized by hydrothermal method using nickel chloride hexahydrate(NiCl2·6H2O), cobalt sulphate heptahydrate(CoSO4·7H2O) and red phosphorus as starting materials, graphene oxide(GO) as a supporter. The as-obtained samples were characterized by XRD, FE-SEM and TEM. The result shows that, NiCoP nanoparticles are assembled on the surface of rGO nanomaterial, and the size of NiCoP particles is about 20 nm. The adsorption removal property tests of the as-prepared Ni CoP and NiCoP/rGO composites were also investigated. Based on the Raman spectrum result, it is obvious that the GO has been reduced completely into rGO. |
