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采用偏NH_4VO_3和TiO_2为前驱体制备选择性催化还原(SCR)催化剂涂层所需浆料,将浆料浸涂在蜂窝陶瓷载体上,得到整体涂覆式SCR催化剂。研究了SiO_2溶胶、H_3PO_4及H_3NO_3对催化剂涂层耐久性及活性的影响。在模拟评价装置上对催化剂活性进行了评价。结果表明,SiO_2溶胶和H_3PO_4对催化剂涂层耐久性具有明显改善作用,质量分数8%的SiO_2溶胶和4%的H_3PO_4使催化剂涂层脱落率从32.71%降至4.08%和17.89%;V_2O_5-WO_3/TiO_2-4%SiO_2溶胶催化剂表现出较高的活性和选择性,新鲜催化剂NO的起燃温度(T_(50))为205℃,随着H_3PO_4添加量的增加,催化剂低温活性逐渐降低,高H_3PO_4添加量时,催化剂表面被H_3PO_4覆盖,大部分与钛及钒键连接的羟基基团被P—OH所取代,催化剂SCR活性降低。
A slurry of selective catalyst (SCR) catalyst coating was prepared by using partial NH_4VO_3 and TiO_2 as precursors, and the slurry was dip-coated on a honeycomb ceramic carrier to obtain an overall coated SCR catalyst. The effects of SiO 2 sol, H_3PO_4 and H_3NO_3 on the durability and activity of the catalyst coating were studied. The catalyst activity was evaluated on a simulated evaluation device. The results show that the SiO 2 sol and H_3PO_4 have a significant improvement on the durability of the catalyst coating. The degradation rate of the catalyst coating decreases from 32.71% to 4.08% and 17.89% with 8% SiO_2 sol and 4% H_3PO_4, respectively. V_2O_5-WO_3 / TiO 2 -4% SiO 2 sol catalyst exhibited higher activity and selectivity. The ignition temperature (T 50) of fresh catalyst was 205 ℃. With the increase of H 3 PO 4 addition, the activity of the catalyst decreased gradually, and the high When the amount of H_3PO_4 was added, the surface of the catalyst was covered by H_3PO_4. Most of the hydroxyl groups linked to the titanium and vanadium bonds were replaced by P-OH, and the SCR activity decreased.