Enhancement of Activity and Sulfur Resistance of CeO2 Supported on TiO2-SiO2 for the Selective Catalytic Reduction of NO by NH3
Enhancement of Activity and Sulfur Resistance of CeO2 Supported on TiO2-SiO2 for the Selective Catalytic Reduction of NO by NH3
复制标题
TiO2-SiO2负载CeO2增强NH3选择性催化还原NO的活性和抗硫性
DOI：
10.1021/es3001773
复制
发表时间：
2012-06-05
影响因子：
11.4
通讯作者：
Hao, Jiming
中科院分区：
文献类型：
--
作者：
Liu, Caixia;Chen, Liang;Hao, Jiming
采用湿浸渍法制备了一系列新型金属氧化物负载CeO2催化剂，并对其NH3-SCR活性进行了研究。 Ti/Si质量比为3/1的Ce/TiO2-SiO2催化剂在250-450℃温度范围内表现出优异的NH3-SCR活性和高N-2选择性。表征结果表明，活性增强与载体材料的性能相关。铈高度分散在TiO2-SiO2二元金属氧化物载体上，与单一金属氧化物载体相比，Ti和Si的相互作用导致催化剂表面上Ce4+向Ce3+的转化率更高。由于SiO2的添加导致Ce/TiO2-SiO2上的酸位数量增加，NH3吸附能力显着提高。所有这些因素在高 SCR 活性中发挥了重要作用。更重要的是，Ce/TiO2-SiO2表现出很强的抗SO2和H2O中毒的能力。添加SiO2后，TiO2-SiO2载体上的路易斯酸位数量没有减少，但布朗斯台德酸位数量增加。 SiO2的引入进一步削弱了Ce/TiO2-SiO2催化剂表面的碱性，导致与Ce/TiO2相比，Ce/TiO2-SiO2催化剂表面不易积聚硫酸盐。
A series of novel metal-oxide-supported CeO2 catalysts were prepared via the wet impregnation method, and their NH3-SCR activities were investigated. The Ce/TiO2-SiO2 catalyst with a Ti/Si mass ratio of 3/1 exhibited superior NH3-SCR activity and high N-2 selectivity in the temperature range of 250-450 degrees C. The characterization results revealed that the activity enhancement was correlated with the properties of the support material. Cerium was highly dispersed on the TiO2-SiO2 binary metal oxide support, and the interaction of Ti and Si resulted in greater conversion of Ce4+ to Ce3+ on the surface of the catalyst compared to that on the single metal oxide supports. As a result of in the increased number of acid sites on Ce/TiO2-SiO2 that resulted from the addition of SiO2, the NH3 adsorption capacity was significantly improved. All of these factors played significant roles in the high SCR activity. More importantly, Ce/TiO2-SiO2 exhibited strong resistance to SO2 and H2O poisoning. After the addition of SiO2, the number of Lewis-acid sites was not decreased, but the number of Bronsted-acid sites on the TiO2-SiO2 carrier was increased. The introduction of SiO2 further weakened the alkalinity over the surface of the Ce/TiO2-SiO2 catalyst, which resulted in sulfate not easily accumulating on the surface of the Ce/TiO2-SiO2 catalyst in comparison with Ce/TiO2.