Synthesis Of Nano-copper Chromite And Composite Catalysts And Their Characterization As Catalyst

Copper chromite with the tetragonally distorted normal spinel structure has been considered as one of the most effective catalyst for HTPB propellants. However, the preparation of copper chromite need of high temperature treatment which lead the prepared nanoparticles reunite easily and reduces the catalytic efficiency as nano-catalysts. Nano-copper chromite and composite catalysts (such as the introduction of lead ions and graphene act as a carrier) were synthesized in this article, and studied their catalytic effect on the thermal decomposition of AP as well as the catalytic mechanism. The main contents are as follows:(1) Copper chromite nanoparticles were prepared by coprecipitation with PEG-400 act as dispersing agent and ammonia as the precipitating agent.Copper chromite with well crystallization and good dispersion was obtained when the Cu/Cr molar ratio is 0.5, the dosage of PEG-400 is 2%, pH of the solution is 7 and the calcination temperature is 600℃. While different Cu-Cr-O composite oxides can be obtained when changing the Cu/Cr molar ratio in materials.(2) Cu-Cr-Pb composites which are ternary complex of CuCr2O4, PbCrO4 and Cr2O3were synthesized by coprecipitation with changing Cu/Pb molar ratio and controlling the amount of Cr in raw materials. The introduction of Pb has some impacts on the size and morphology of copper chromite.(3) CuCr2O4/graphene composites were prepared by two-step method with graphene as a carrier. The dispersibility of copper chromite dispersed on graphene is superior to that of single component copper chromite.(4) The catalysis of as-synthesized copper chromite, Cu-Cr-O composite oxides, Cu-Cr-Pb composites and CuCr2O4/graphene composite particles on thermal decomposition of AP was investigated by DSC. The results show that copper chromit, Cu-Cr-O composite oxides, Cu-Cr-Pb composites and CuCr2O4/graphene composite particles can catalyze AP effectively with lowering apparent activation energy E and the AP pre-exponential factor A and increasing the decomposition reaction rate constant k.