Temperature-programmed desorption studies on ZSM—5 zeolites
1984; Elsevier BV; Volume: 4; Issue: 1 Linguagem: Inglês
10.1016/0144-2449(84)90063-0
ISSN1873-3115
AutoresKuei‐Jung Chao, Bin-Haw Chiou, Chih-Chen Cho, Shiow-Yau Jeng,
Tópico(s)Catalytic Processes in Materials Science
ResumoThe temperature programmed desorption of NH4-ZSM—5, Na,TPA-ZSM—5, and ammonia on H-ZSM—5, Na,H-ZSM—5 and silicalite zeolites has been investigated using thermoconductivity, on-line mass spectrometry automatic pH titration. The high temperature desorption peaks at 380° ∼ 450°C or 400° ∼ 470°C are associated with the internal NH4+ or TPA+ ions in zeolite ZSM—5. The external acid sites on zeolite surface are characterized by ammonia desorption at 230°C or trialkylamine desorption at 250°C. The Na adsorption centres for ammonia give rise to a 300°C desorption peak in t.p.d, curve of ammonia on Na,H-ZSM—5.
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