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首页> 外文期刊>RSC Advances >Migration, reactivity, and sulfur tolerance of copper species in SAPO-34 zeolite toward NOx reduction with ammonia
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Migration, reactivity, and sulfur tolerance of copper species in SAPO-34 zeolite toward NOx reduction with ammonia

机译：氨中SAPO-34沸石中铜离子对NO x 还原的迁移，反应性和耐硫性

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Cu/SAPO-34 catalysts were prepared by wet impregnation and ion-exchange methods, and both the catalysts were hydrothermally treated at 750 °C in 10 vol% H2O/air for 24 h. Subsequently, the as-received and hydrothermally treated catalysts were exposed to a sulfur poisoning treatment at 350 °C in 100 ppm SO2/10 vol% H2O/air for 24 h and examined for NOx conversion. Sulfur poisoning considerably decreased the NOx conversion efficiency of the catalysts at low temperatures. In contrast, it improved the high-temperature selective catalytic reduction (SCR) activities of the as-received catalysts. The ion-exchange-prepared catalysts displayed higher sulfur tolerance than the impregnation-prepared catalysts at 150–350 °C. The electron paramagnetic resonance, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy and H2-temperature-programmed reduction results showed that sulfur poisoning significantly influenced the migration of the copper species and thereby the amount of active isolated Cu2+. More dispersed CuSO4 was produced on the ion-exchange-prepared catalysts than on the impregnation-prepared catalysts after sulfur poisoning. The dispersed CuSO4 showed considerably higher SCR activity than the crystalline CuSO4. Both the dispersed CuSO4 and remaining isolated Cu2+ determined the low-temperature SCR behavior of the sulfur-poisoned catalysts.
机译：采用湿法浸渍和离子交换法制备Cu / SAPO-34催化剂，并在750°C，10vol％H 2 O /中进行水热处理。通风24小时。随后，将收到的经水热处理的催化剂在100 ppm SO 2 / 10 vol％H 2 O /空气24小时，并检查NO x 的转化率。硫中毒大大降低了催化剂在低温下的NO x 转化效率。相反，它改善了原样催化剂的高温选择性催化还原（SCR）活性。在150–350°C下，离子交换制备的催化剂显示出比浸渍制备的催化剂更高的耐硫性。电子顺磁共振，X射线光电子能谱，能量色散X射线能谱和H 2 温度程序控制的还原结果表明，硫中毒显着影响了H2的迁移。铜的种类，从而分离出活性的Cu 2 + 。硫中毒后，在离子交换制备的催化剂上生成的CuSO 4 分散性更高。分散的CuSO 4 的SCR活性明显高于结晶CuSO 4 的SCR活性。分散的CuSO 4 和剩余的孤立的Cu 2 + 都决定了硫磺的低温SCR行为。中毒的催化剂。

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