| 摘要： |
In this work, we report the synthesis of crystalline Cu-SSZ-13 catalyst by using different silica sources, including colloidal silica (silica sol), gelatinous silica (silica gel) and tetraethyl orthosilicate (TEOS). These samples were characterized by various techniques (SEM, XRD, BET, ICP-OES, H-2-TPR, NH3-TPD, XAFS). The sample prepared by using silica sol exhibited regular morphology and uniform particle dispersions. The results also showed that different acidities and Cu ions distributions were present on these Cu-SSZ-13 catalysts. The various silica sources affected the physicochemical properties and subsequent catalytic performances in the selective catalytic reduction of NO by NH3 (NO-SCR). Cu-SSZ-13 from TEOS showed obvious advantage for the catalytic activity at low-temperature region (< 200 degrees C). However, Cu-SSZ-13 from silica gel performed superior overall catalytic activity (200-600 degrees C) in the three samples. Furthermore, Cu-SSZ-13 from silica sol displayed superior hydrothermal stability after the same hydrothermal treatment for the three samples, despite of the similar movement of Cu2+ ions under aging process. Thus, the choice of silica sol as precursor source is more profitable for synthesis of Cu-SSZ-13. |
