摘要
分别制备了磷钨酸、磷酸、偏钨酸铵及磷酸+偏钨酸铵改性的CeO_2催化剂,用于NO的NH3选择性催化还原反应(NH3-SCR),对酸改性的作用进行了研究。结果表明,不同酸改性后的CeO_2催化剂均含有弱酸和中强酸位,但酸量差别明显,依次为:磷钨酸/CeO_2>偏钨酸铵/CeO_2>磷酸+偏钨酸铵/CeO_2>磷酸/CeO_2。由于磷钨酸改性的CeO_2催化剂中P与W之间相互作用,导致磷钨酸/CeO_2催化剂表面弱酸及中强酸含量较多,Ce物种和O物种相对活跃,有利于NH3的吸附、活化和NH3-SCR反应的进行;因此,磷钨酸改性的CeO_2催化剂活性最佳,在225-450℃下NO转化率高于90%。
A series of CeO2 catalysts was modified with different acids including phosphotungstic acid （P-W）, phosphate acid （P）, partial ammonium tungstate （W）, and phosphate acid plus partial ammonium tungstate （P＋W）; the effect of acid modification on the performance of CeO2 catalyst in the selective catalytic reduction of NO with ammonia （NH3-SCR） was then investigated. The results indicated that the CeO2 catalyst after acid modification possesses abundant surface acid sites of weak-medium strength and the acid quantity of various catalysts follows the order of P-W/CeO2 〉W/CeO2 〉P＋W/CeO2 〉P/CeO2. Due to the interaction between P and W species, the P-W/CeO2 catalyst modified with phosphotungstic acid exhibits high amount of weak-medium surface acid sites and active Ce and O species, which may promote the adsorption and activation of NH3 and then enhance its catalytic activity in the NH3-SCR of NO; over the P-W/CeO2 catalyst, the conversion of NO keeps above 90% at 225-450℃.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2016年第10期1259-1265,共7页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金(U1137603)资助~~
关键词
酸改性
磷钨酸
氧化铈
选择性催化还原
NO脱除
acid modification
phosphotungstic acid
CeO2
selective catalytic reduction with ammonia
NO removal
