Preparation Of Supported Pt/Pd-based Catalysts For Catalytic Combustion Of Hydrocarbon Fuels

Fuel tank explosion problem has always been the focus of airworthiness and safety conceems.Comparing with traditional approach,the Green Onboard Inert Gas Generation System(GOBIGGS)towards the inert of fuel tank posesses obvious advantages and strong competitiveness.With a low-pressure pump,the system can transport the mixture of fuel vapor and air in the fuel tank to the catalytic combustion cell.After complete oxidation with efficient catalyst,the generated CO2 and unreacted NZ would be transported back to the fuel tank as inert gas,during which the oxygen level would be quickly reduced within the safe concentration to ensure the safety of fuel tank.Consequently,the performance of the catalytic combustion cell,the core component of GOBIGGS,is directly related to inert effect of the whole system.Noble metallic catalysts have been the focus of research in catalytic combustion because of their good catalytic activity at low temperature.In this work,a series of Pt-based or Pd-based catalysts have been prepared and characterized by means of XRD,XPS,SEM,TEM,and EDX.The catalytic activity on the hydrocarbon fuels has been tested on a self-designed catalytic combustion apparatus.The influences of loading amount,types of supports,particle sizes and preparation methods on the activity of the catalysts have been investigated.As for mono-component noble metallic catalysts,the catalytic activity can be promoted by increasing noble metal loading.Pt nanoparticles prepared with supports of small size exhibit small diameter and satisfactory dispersion,which behave better in catalytic combustion.Pt loaded on H-USY compared to other supports had the best catalytic activity,on which complete catalytic combustion temperature of n-dodecane can be as low as 280?.The catalytic activity is still maintained after 30 h continuous reaction.While for bi-component noble metallic catalysts,the catalytic activity of catalysts prepared by co-impregnation method is better than that by continuous impregnation method.The catalytic activity of Pt1Pd0.5/H-USY and Pt1Rh0.5/H-USY is particularly good due to the synergistic effect between two metals.The effects of different morphologies on the catalytic activity of Pt-s@CeO2/?-A12O3,Pd-s@CeO2/?-Al2O3,Pd-c@CeO2/?-Al2O3 and Pd-o@CeO2/?-Al2O3 core-shell structure have been investigated.The effect of the addition amount of cerium on the activity of Pt/Pd-based core-shell structure catalyst is also studied,the best molar ratio of noble metal to cerium is from 1:1 to 1:2.