To enhance the catalytic activity of copper ferrite(CuFe_(2)O_(4))nanoparticle and promote its application as combustion catalyst,a low-cost silicon dioxide(SiO_(2))carrier was employed to construct a novel CuFe_(2)O_...To enhance the catalytic activity of copper ferrite(CuFe_(2)O_(4))nanoparticle and promote its application as combustion catalyst,a low-cost silicon dioxide(SiO_(2))carrier was employed to construct a novel CuFe_(2)O_(4)/SiO_(2)binary composites via solvothermal method.The phase structure,morphology and catalytic activity of CuFe_(2)O_(4)/SiO_(2)composites were studied firstly,and thermal decomposition,combustion and safety performance of ammonium perchlorate(AP)and 1,3,5-trinitroperhydro-1,3,5-triazine(RDX)with it affecting were then systematically analyzed.The results show that CuFe_(2)O_(4)/SiO_(2)composite can remarkably either advance the decomposition peak temperature of AP and RDX,or reduce the apparent activation energy at their main decomposition zone.Moreover,the flame propagation rate of RDX was promoted by about 2.73 times with SiO_(2)content of 3 wt%,and safety property of energetic component was also improved greatly,in which depressing the electrostatic discharge sensitivity of pure RDX by about 1.89 times.In addition,the effective range of SiO_(2)carrier content in the binary catalyst is found to be 3 to 5 wt%.Therefore,SiO_(2)opens a new insight on the design of combustion catalyst carrier and will promote the application of CuFe_(2)O_(4)catalyst in solid propellant.展开更多
The electrochemical reduction of CO2 on copper electrode was investigated in acetonitrile(MeCN),dimethyl formamide(DMF)and dimethyl sulfoxide(DMSO)containing 0.1 mol/L tetraethylammonium bromioe(TEABr)by cyclic voltam...The electrochemical reduction of CO2 on copper electrode was investigated in acetonitrile(MeCN),dimethyl formamide(DMF)and dimethyl sulfoxide(DMSO)containing 0.1 mol/L tetraethylammonium bromioe(TEABr)by cyclic voltammetry and chronocoulometry at 298 K and under atmospheric pressure.There were obviously irreversible one-electron reduction peaks after saturated with CO2 on copper electrode in three solvents,which generated anion radical of CO2.The influence of scan rate was also studied by cyclic voltammetry.The diffusion coefficients of CO2 in MeCN,DMF and DMSO were 8.981×10-6,1.019×10-6 and 1.032×10-6 cm2/s and the transfer coefficients were 0.064,0.042 and 0.059,respectively.These results show that the electroreduction of CO2 was an irreversible diffusion controlled process.展开更多
The LaCoO3 and 1%,10%,20%,30% doped Cu-LaCoO3 were prepared and studied. Two pretreated process were studied to investigate the effect of pretreating process of the catalysts on the reduction of SO2 by CO. One was usi...The LaCoO3 and 1%,10%,20%,30% doped Cu-LaCoO3 were prepared and studied. Two pretreated process were studied to investigate the effect of pretreating process of the catalysts on the reduction of SO2 by CO. One was using the mixture of SO2 and CO for catalysts sulfurized and poisoned in the presence of oxygen and the other was using SO2 and CO pre-reduced in the absence of oxygen. The evaluations were based on the SO2 conversion as well as sulfur selectivity and COS produced in a gradientless, quartz tubular packed-bed reactor. It was found that the catalysts sulfurized and poisoned under the mixture of SO2 and CO in the presence of oxygen could sustain its activity better than the pre-reduced catalysts. The activity decrease of the sulfurized and poisoned catalysts was very small after 4 h reaction. But for the two pre-reduced catalysts, SO2 conversion was only 17% over one 10% doped Cu-LaCoO3 and the other was deactivated after 140 min reaction. It was also found that all the doped Cu catalysts, sulfurized and poisoned in the presence of oxygen, presented higher oxygen resistance than the pre-reduced catalysts after reaction. The SO2 conversion of all the doped Cu catalysts decreased a little over 40 h reaction, while the activity of un-doped LaCoO3 was lowered to only 0.2 times of the initial activity. The other result showed that the COS formation was minimized in the doped Cu catalysts. From the results, it could be concluded that the 10% Cu-LaCoO3 was the most effective of the catalysts for removing sulfur with little COS formation.展开更多
基金the National Nature Science Foundation of China(Grant Nos.21673178,22105160)the Natural Science Foundation of Shaanxi Province(Grant No.2023-JC-ZD-07)+1 种基金the Foundation of Key Laboratory of Defense Science and technology(Grant No.6142603032213)the Key Science and Technology Innovation Team of Shaanxi Province(Grant No.2022TD-33).
文摘To enhance the catalytic activity of copper ferrite(CuFe_(2)O_(4))nanoparticle and promote its application as combustion catalyst,a low-cost silicon dioxide(SiO_(2))carrier was employed to construct a novel CuFe_(2)O_(4)/SiO_(2)binary composites via solvothermal method.The phase structure,morphology and catalytic activity of CuFe_(2)O_(4)/SiO_(2)composites were studied firstly,and thermal decomposition,combustion and safety performance of ammonium perchlorate(AP)and 1,3,5-trinitroperhydro-1,3,5-triazine(RDX)with it affecting were then systematically analyzed.The results show that CuFe_(2)O_(4)/SiO_(2)composite can remarkably either advance the decomposition peak temperature of AP and RDX,or reduce the apparent activation energy at their main decomposition zone.Moreover,the flame propagation rate of RDX was promoted by about 2.73 times with SiO_(2)content of 3 wt%,and safety property of energetic component was also improved greatly,in which depressing the electrostatic discharge sensitivity of pure RDX by about 1.89 times.In addition,the effective range of SiO_(2)carrier content in the binary catalyst is found to be 3 to 5 wt%.Therefore,SiO_(2)opens a new insight on the design of combustion catalyst carrier and will promote the application of CuFe_(2)O_(4)catalyst in solid propellant.
文摘The electrochemical reduction of CO2 on copper electrode was investigated in acetonitrile(MeCN),dimethyl formamide(DMF)and dimethyl sulfoxide(DMSO)containing 0.1 mol/L tetraethylammonium bromioe(TEABr)by cyclic voltammetry and chronocoulometry at 298 K and under atmospheric pressure.There were obviously irreversible one-electron reduction peaks after saturated with CO2 on copper electrode in three solvents,which generated anion radical of CO2.The influence of scan rate was also studied by cyclic voltammetry.The diffusion coefficients of CO2 in MeCN,DMF and DMSO were 8.981×10-6,1.019×10-6 and 1.032×10-6 cm2/s and the transfer coefficients were 0.064,0.042 and 0.059,respectively.These results show that the electroreduction of CO2 was an irreversible diffusion controlled process.
文摘The LaCoO3 and 1%,10%,20%,30% doped Cu-LaCoO3 were prepared and studied. Two pretreated process were studied to investigate the effect of pretreating process of the catalysts on the reduction of SO2 by CO. One was using the mixture of SO2 and CO for catalysts sulfurized and poisoned in the presence of oxygen and the other was using SO2 and CO pre-reduced in the absence of oxygen. The evaluations were based on the SO2 conversion as well as sulfur selectivity and COS produced in a gradientless, quartz tubular packed-bed reactor. It was found that the catalysts sulfurized and poisoned under the mixture of SO2 and CO in the presence of oxygen could sustain its activity better than the pre-reduced catalysts. The activity decrease of the sulfurized and poisoned catalysts was very small after 4 h reaction. But for the two pre-reduced catalysts, SO2 conversion was only 17% over one 10% doped Cu-LaCoO3 and the other was deactivated after 140 min reaction. It was also found that all the doped Cu catalysts, sulfurized and poisoned in the presence of oxygen, presented higher oxygen resistance than the pre-reduced catalysts after reaction. The SO2 conversion of all the doped Cu catalysts decreased a little over 40 h reaction, while the activity of un-doped LaCoO3 was lowered to only 0.2 times of the initial activity. The other result showed that the COS formation was minimized in the doped Cu catalysts. From the results, it could be concluded that the 10% Cu-LaCoO3 was the most effective of the catalysts for removing sulfur with little COS formation.
