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分别用钾盐以及Co_3O_4对铈锆复合氧化物进行单掺杂和复合掺杂,制得一系列钾、钴改性CeO_2-ZrO_2催化剂,采用溶胶凝胶浸渍法将所制催化剂负载于SiC上,并用氮气吸附-脱附(BET)、X射线粉末衍射(XRD)、氢气程序升温还原(H_2-TPR)和程序升温氧化反应(TPO)等方法考察了钾、钴离子对催化剂结构和催化活性的影响。结果表明:采用钴修饰铈锆复合氧化物催化剂后能够明显提高其表面氧的活性,从而提高催化剂的催化能力;当催化剂中存在钾物种时,主要通过改善碳烟与催化剂的接触状况而有效促进碳烟的燃烧;与未负载催化剂相比,负载后各催化剂催化碳烟燃烧能力都出现不同程度的降低;各负载型催化剂的催化活性由大到小的顺序为K-Co-Ce-Zr/SiC>K-Ce-Zr/SiC>Co-Ce-Zr/SiC>Ce-Zr/SiC>Co-Zr/SiC;K-Co-Ce-Zr/SiC催化体系在经过5次循环使用后仍具有较高的催化碳烟燃烧能力,显示出较好的稳定性。
A series of potassium and cobalt modified CeO_2-ZrO_2 catalysts were prepared by single-doping and compound doping of cerium-zirconium composite oxide with potassium salt and Co_3O_4 respectively. The prepared catalyst was supported on SiC by sol-gel impregnation method, The effects of potassium and cobalt ions on the structure and catalytic activity of the catalysts were investigated by means of nitrogen adsorption-desorption (BET), X-ray powder diffraction (XRD), hydrogen temperature programmed reduction (H_2-TPR) and temperature programmed oxidation (TPO) influences. The results show that the cobalt modified cerium-zirconium composite oxide catalyst can significantly improve the surface oxygen activity, thereby enhancing the catalyst catalytic capacity; when potassium species present in the catalyst, mainly by improving the contact state of soot and catalyst and effectively promote Compared with the unburned catalyst, the catalytic activity of each catalyst for soot combustion decreased with different degrees. The catalytic activity of each supported catalyst decreased from K-Co-Ce-Zr / SiC-K-Ce-Zr / SiC> Ce-Zr-SiC> Ce-Zr / SiC> Co-Zr / Higher catalytic activity of soot combustion, showing good stability.