In situ Synthesis of Cu-SAPO-34/Cordierite for the Catalytic Removal of NOx from Diesel Vehicles by C3H8

A Cu-SAPO-34/cordierite catalyst was prepared by in situ hydrothermal synthesis. The morphology and structure of the Cu-SAPO-34/cordierite samples were characterized by X-ray diffraction, scanning electron microscopy, and physical adsorption-desorption analyzer. The removal of NOx from simulated diesel vehicle exhaust gas was carried out using a fixed-bed reactor. The effects of C3H8, O2 concentrations, and water vapor on the activity of the catalyst were studied. The results indicate that the Cu-SAPO-34 coatings obtained by the in situ synthesis are firm and compact, and the loading amount was found to be more than 20% after one synthesis operation. The surface areas of the Cu-SAPO-34/cordierite catalysts increase greatly compared with that of cordierite. The active Cu component prepared through in situ synthesis can significantly improve the activity of selective catalytic reduction of NOx by C3H8. NOx reduction over the Cu-SAPO-34/cordierite catalyst is more than 60% between 500 and 650 °C. The NOx conversion decreases after the addition of 10% water vapor to the feed gas but the deactivation caused by water vapor is not permanent.

摘要：采用原位水热法制备了 Cu-SAPO-34/堇青石整体式催化剂, 运用 X 射线衍射、扫描电镜和 N2 吸附-脱附等技术对其进行了表征, 并在固定床反应器上评价了其催化丙烷还原模拟柴油机车尾气中 NOx 性能, 考察了丙烷和 O2 浓度以及水蒸气对催化剂性能的影响. 结果表明, 所制整体式催化剂中 Cu-SAPO-34 涂层与载体结合牢固紧密, 经一次操作 Cu-SAPO-34 负载量大于 20%, 且其比表面积较载体显著增加. 另外, Cu 的加入能显著提高催化剂上丙烷选择性催化还原 NOx 的活性, 在 500 sim 650 °C NOx 浓度可降低 60% 以上. 当原料气中添加 10% 水蒸气后, NOx 转化率有所降低, 但停加水蒸气后, 催化剂活性可部分恢复.

Graphical abstractA Cu-SAPO-34/cordierite catalyst was prepared by in situ hydrothermal synthesis. The catalyst had a firm and compact Cu-SAPO-34 coating and its NOx-SCR by C3H8 activity depends on the O2 concentration in the feed gas.Figure optionsDownload full-size imageDownload as PowerPoint slide