表面磷酸化CeO_(2)选择性还原NO及其碱金属耐受性  

Surface phosphorylation of CeO_(2) for selective reduction of NO and its alkali metal tolerance

作　　者：李顺 胡方方 王闻之 蔡思翔[1] 姜宏[1] LI Shun;HU Fangfang;WANG Wenzhi;CAI Sixiang;JIANG Hong(State Key Laboratory of Marine Resources Utilization of the South China Sea,Special Glass Laboratory of Hainan Province,College of Materials Science and Engineering,Hainan University,Haikou 570228,Hainan,China)

机构地区：[1]海南大学材料科学与工程学院,南海海洋资源利用国家重点实验室,海南省特种玻璃重点实验室,海南海口570228

出　　处：《精细化工》2022年第5期995-1003,1053,共10页Fine Chemicals

基　　金：海南省自然科学基金青年基金项目(221QN0859);海南省重点研发计划项目(ZDYF2020015);海南大学科研平台建设(ZY2019HN09)。

摘　　要：以Ce(NO_(3))_(3)·6H_(2)O和(NH_(2));PO;·3H_(2)O为原料,采用浸渍法制备了磷酸化CeO_(2)催化剂。以NH_(2)为还原剂,考察了磷酸化CeO_(2)催化剂氨选择性催化还原(NH_(2)-SCR)NO的脱硝性能。利用XRD、N_(2)吸附-脱附、XPS、NH_(2)-TPD、原位漫反射红外光谱对催化剂结构和性能进行了表征。结果表明,在250~500℃范围内,磷酸化CeO_(2)催化剂(CeP_(0.05))使NO的转化率在90%以上,且在碱金属和碱土金属中毒后,在300~400℃范围内,磷酸化CeO_(2)催化剂使NO的转化率仍保持在80%以上。磷酸化CeO_(2)催化性能的增强可归因于酸位点数量的增加,尤其是BrФnsted酸位点数量的增加。磷酸化改性产生更多的Ce^(3+)和化学吸附氧,提高了催化剂的氧化还原能力。当碱金属沉积在催化剂上时,碱金属被诱导迁移到磷酸化CeO_(2)的表面与Ce—O—P碱捕获位点结合,从而阻止碱金属攻击Ce^(4+)活性位点。Phosphorylated CeO_(2)catalysts were firstly prepared by impregnation method using Ce(NO_(3))_(3)·6H_(2)O and(NH_(4))_(3)PO_(4)·3H_(2)O as raw materials,and then its denitration performance over selective catalytic reduction of NO using NH_(2)as reducing agent(NH_(2)-SCR)was investigated.The structures and properties of catalysts were characterized by XRD,N_(2)adsorption-desorption,XPS,NH_(2)-TPD and in situ DRIFTS.The results showed that the NO conversion rate was more than 90%in temperature range 250~500℃,and remained above 80%in the range of 300~400℃even after phosphorylated Ce O;catalyst was poisoned by alkali metals and alkaline earth metals.The enhanced catalytic performance of phosphorylated CeO_(2)was attributed to the increase in the number of acid,especially BrФnsted acid sites.The phosphorylation modification produced more Ce^(3+) and chemisorbed oxygen,which improved the redox capacity of the catalyst.When deposited on the catalyst,the alkali metals were induced to migrate to the surface of phosphorylated CeO_(2)and bound to the Ce—O—P base capture site,being prevented from attacking the Ce^(4+) active site.

关 键 词：CeO_(2) 磷酸化 氨选择性催化还原 碱金属耐受性 氮氧化物 环境保护 

分 类 号：X701[环境科学与工程—环境工程] TQ426[化学工程]