ZrO2掺杂的V2O5/TiO2催化剂表征及催化还原NOx

采用共沉淀法制备出不同锆掺杂量的钛锆复合载体(TiO2-ZrO2),运用XRD和BET研究其微观结构,结果显示钛锆物质的量之比1∶1时复合载体具有最大的比表面积,可达256.01 m.2g-1.以此为载体制备了V2O5/TiO2-ZrO2催化剂,并添加少量CeO2对其改性.采用XRD、BET、H2-TPR、原位FT-IR等手段研究其活性组分的表面分散状态、氧化还原特性和表面酸性.结果显示,V2O5高度分散在载体上;与纯V2O5相比,复合载体上V2O5的还原峰向低温方向发生了偏移;催化剂表面包含了大量的B酸和L酸.模拟氨气催化还原NO(NH3-SCR)的脱硝反应活性测试表明,V2O5/TiO2-ZrO2催化剂具有较好的热稳定性和较宽的活性窗口,少量CeO2的加入提高了催化剂的低温活性.

Characteriration of ZrO_2-doped V_2O_5/TiO_2 catalyst and its catalytic reduction of NO_x by NH_3

TiO2-ZrO2 binary oxides with various compositions were synthesized by a co-precipitation method and were characterized by using X-ray diffraction and BET surface area technique.It was found that TiO2-ZrO2 composite(1 ∶ 1 molar ratio of Ti to Zr) had a high specific surface area(256.01 m2 · g-1).Binary oxides V2O5 and V2O5-CeO2 supported on TiO2-ZrO2(1 ∶ 1 molar ratio) catalysts had been characterized by XRD,BET,H2-TPR,in situ FT-TR and acticity test for removal NO by NH3.The results showed that V2O5 was highly dispersed on the TiO2-ZrO2 support.H2-reduction peak of V2O5 supported on TiO2-ZrO2 was shifted to lower temperature compared with bulk V2O5 and there were significant amounts of Brnsted and Lewis acid sites.With a loading of CeO2,an obvious increase of surface acid sites and redox property was observed.The catalytic activity measurement indicated that the V2O5/ TiO2-ZrO2 sample exhibited excellent stability at high temperature and displayed better catalytic activity in a wide temperature range.The addition of CeO2 had evidently improved the NO conversion at low temperatures.