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采用漫反射红外光谱原位考察了 2 98～ 773K范围H2 O ,NH3 和NO在SAPO 34分子筛上的吸附行为。结果表明 ,SAPO 34对水的吸附是可逆的 ,对NH3 和NO的吸附则是不可逆的。吸附水在 6 2 3K完全脱附 ,脱水后的分子筛在 36 2 5～ 36 0 0cm-1出现表征桥式羟基 (Si OH Al)的特征峰。发现SAPO 34对NH3 和NO均有良好的吸附 催化活性。吸附NH3 后 ,桥式羟基消失 ,位于 3135 ,30 32和 1399cm-1处在 42 3K时出现三个吸收峰 ,在 6 73K达最大 ,且峰高分别是SAPO 34骨架峰高的 3 9,1 7和 6 7倍 ;吸附NO后 ,在室温下位于 136 4cm-1也观测到一强而尖锐的峰 ,其强度与骨架峰强度相当。对这些峰进行归属表明 ,吸附NH3 和NO后产生了新的物种NO-3 。
The adsorption behavior of H 2 O, NH 3 and NO on the SAPO 34 zeolite in the range of 2 98-773 K was investigated in situ using diffuse reflectance infrared spectroscopy. The results show that the adsorption of water by SAPO 34 is reversible and the adsorption of NH3 and NO is irreversible. The adsorbed water was completely desorbed at 623K, and the molecular sieve after dehydration showed the characteristic peak of SiOH Al at 3625 ~ 3600cm-1. SAPO 34 was found to have good adsorption catalytic activity on both NH3 and NO. After adsorption of NH3, the bridged hydroxyl disappears and three absorption peaks appear at 423K at 3135, 3032 and 1399cm-1, reaching the maximum at 673K and the peak heights are 39.1 and 7 and 67 times, respectively. After adsorbed NO, a strong and sharp peak was also observed at 136 4cm-1 at room temperature, which was comparable to the peak intensity of the framework. The assignment of these peaks shows that the adsorption of NH3 and NO produced a new species of NO-3.