The effect of various templates on the NH3-SCR activities over Cu/SAPO-34 catalysts
The effect of various templates on the NH3-SCR activities over Cu/SAPO-34 catalysts
复制标题
DOI：
10.1016/j.cej.2014.01.008
复制
发表时间：
2014-05
影响因子：
15.1
通讯作者：
Tie Yu;Dequan Fan;Teng Hao;Jun Wang;Meiqing Shen;Wei Li
中科院分区：
文献类型：
--
作者：
Tie Yu;Dequan Fan;Teng Hao;Jun Wang;Meiqing Shen;Wei Li
研究了四种 Cu/SAPO-34 催化剂的不同酸性质对 NH3-SCR 活性的影响，这些 SAPO-34 载体通过不同的模板合成，产生不同的 Si 配位结构。通过 XRD、SEM、NMR、NH3-TPD、NH3 氧化和动力学测试来表征 SAPO-34 载体中的 Si 配位结构及其对 NH3-SCR 活性的作用。 29Si NMR和NH3-TPD结果表明模板影响了SAPO-34载体中的Si配位结构，而Si配位结构进一步调节了Cu/SAPO-34催化剂的酸性质和Cu物种分布。四种 Cu/SAPO-34 催化剂在 120–600 °C 期间表现出不同的 NO 转化率，尽管它们通过离子交换法含有相似的 Cu 负载量。在低温范围内，动力学结果证明各种Si配位结构并不影响NH3-SCR的表观活化能(Ea)。但发现酸密度与NO转化率有关。此外，NH3氧化和NH3-SCR在高温范围内是竞争反应，前者为了竞争NH3消耗而降低了NH3-SCR中NO的转化率。强酸位点可以抑制NH3氧化中的NH3转化，并且发现不同的Si配位结构影响Cu/SAPO-34催化剂上NH3氧化的表观活化能（Ea）。布朗斯台德酸位点上吸附的 NH3 物质在 NH3-SCR 中的活性可能比 NH3 氧化中的活性更高。最后总结了各种酸性质对NH3-SCR活性和NH3氧化的影响。
The influence of various acid properties on the NH3-SCR activities was studied over four Cu/SAPO-34 catalysts, and these SAPO-34 supports were synthesized by various templates to generate diverse Si coordination structures. The XRD, SEM, NMR, NH3-TPD, NH3oxidation and kinetic tests were used to characterize the Si coordination structures in SAPO-34 supports and their roles on the NH3-SCR activities. The29Si NMR and NH3-TPD results showed that the template affected the Si coordination structures in SAPO-34 supports, and Si coordination structures further adjusted the acid properties and the Cu species distribution in Cu/SAPO-34 catalysts. The four Cu/SAPO-34 catalysts performed different NO conversions during 120–600 °C though they contained the similar Cu loading by ion-exchange method. During the low temperature range, the kinetic results proved that various Si coordination structures did not affect the apparent activation energy (Ea) of NH3-SCR. But it was found that the acid densities were related to the NO conversions. In addition, the NH3oxidation and NH3-SCR were competing reactions during the high temperature range, and the former one decreased the NO conversions in NH3-SCR for the competition of NH3consumption. The strong acid sites could inhibit the NH3conversions in NH3oxidation, and it is found that the different Si coordination structures influenced the apparent activation energy (Ea) of NH3oxidation over Cu/SAPO-34 catalysts. It was likely that the adsorbed NH3species on the Brønsted acid sites showed more active in NH3-SCR than NH3oxidation. Finally, the influence of various acid properties on NH3-SCR activities and the NH3oxidation was concluded.