Study On Synthesis Of Fiber Catalyst And The Catalytic Properties For Removal Of Diesel Exhaust

Fiber catalyst showed favourable properties in lower PM combustion temperature and reducing of NO_x. It is most important that fiber catalyst could behave high dilution efficency as particulate filter. As a result, simultaneous removal of nitrogen oxides (NO_x) - particulate matter (PM) was achieved. In this paper, the preparation method of provskite and spinel fiber as well as the principle of NO_x and PM abatement based on catalyst fibers was investigated , which makes foundation for practical fiber catalyst application on diese emission in the future.La_0.9K_0.1CoO₃ fiber catalysts were prepared via a sol-gel process related electronspining procedure. And these fibers could be subsequently converted into La_0.9K_0.1CoO₃ perovskite fibers via carefully calcinations in air at 800°C. The fiber was composed of nanoparticles and the average diameter of the fiber was 500 nm. The La_0.9K_0.1CoO₃ fibers exhibited good catalytic activity for removal of NOx from diesel exhaust at 400°C. Both the ignition temperature and 50% conversion temperature of soot decrease by 150°C. And the corresponding activation energy of carbon oxidation over the fiber catalysts is 237kJ?mol-1, while the value related to the noncatalytic combustion of carbon is 359 kJ?mol-1.Cu1-xKxFe2O4 fibers were synthesized also by combining the sol-gel process with electronspining technique with trasion metal element. With final heathing temperature growing, the diameter of CuFe2O4 gel fiber gradually decreasded, but the size of nanoparticles increased. Therefore, the surface of fibers became rough .Pure spinel fibers with diameter less than 500 nm were obtained by calcinated at 800°C. Cu was partially substituted with K, which hardly affected the micropattern of Cu_1-xK_xFe₂O₄ fibers. The spinel structure of Cu_0.8K_0.2Fe₂O₄ was completely destroyed. In TPR experiment, Cu_0.9K_0.1Fe₂O₄ show great property of simultaneous removal of C and NO. At 600°C, THC is almost competely oxided by Cu0.9K0.1Fe2O4.In this process, H3BO3/aluminium isopropoxide was introduced to improve fiber mechanic property by added glass phase. The product of Al-CuFe2O4 after heated was mainly spinel CuFe₂O₄. Cu₂FeBO₅ was produced by the reaction of B, Fe and Cu.