We have investigated the reaction mechanism for N20 decomposition on Cu13 via density functional theory. It is found that N20 decomposition on the cluster is more prone to be along the Eley-Rideal （ER） pathway in co...We have investigated the reaction mechanism for N20 decomposition on Cu13 via density functional theory. It is found that N20 decomposition on the cluster is more prone to be along the Eley-Rideal （ER） pathway in comparison with the Langmuir-Hinshelwood （LH） channel. There exists structural relaxation for Cu13 cluster in the reaction, which may influence the catalytic activity of cluster for the subsequent N2O decomposition. The core atom in the Cu13 cluster is substituted with the Fe, Co, or Ni to enhance structural stability and prevent from the obvious configuration relaxation in the reaction. Note that these bimetallic clusters are of icosahedra as the Cu13. They have activities for N2O dissociation along ER pathway and the heteroatorn in the cluster can prevent configuration from relaxation. Finally, the Ni@Cu12 cluster can be as a superior catalyst in a complete catalytic cycle via comparison in this study.展开更多
NH_(3) in ambient air directly leads to an increase in the aerosol content in the air. These substances lead to the formation of haze to various environmental problems after atmospheric circulation and diffusion. Cont...NH_(3) in ambient air directly leads to an increase in the aerosol content in the air. These substances lead to the formation of haze to various environmental problems after atmospheric circulation and diffusion. Controlling NH_(3) emissions caused by ammonia escaping from mobile and industrial sources can effectively reduce the NH_(3) content in ambient air. Among the various NH_(3) removal methods, the selective catalytic oxygen method (NH_(3)-SCO) is committed to oxidizing NH_(3) to environmentally harmless H_(2)O and N_(2);therefore, it is the most valuable and ideal ammonia removal method. In this review, the characteristics of loaded and core-shell catalysts in NH_(3)-SCO have been reviewed in the context of catalyst structure-activity relationships, and the H_(2)O resistance and SO2 resistance of the catalysts are discussed in the context of practical application conditions. Then the effects of the valence state of the active center, oxygen species on the catalyst surface, dispersion of the active center and acidic sites on the catalyst performance are discussed comprehensively. Finally, the shortcomings of the existing catalysts are summarized and the catalyst development is discussed based on the existing studies.展开更多
基金supported by the Natural Science Foundation of Fujian Province(2012J01041)
文摘We have investigated the reaction mechanism for N20 decomposition on Cu13 via density functional theory. It is found that N20 decomposition on the cluster is more prone to be along the Eley-Rideal （ER） pathway in comparison with the Langmuir-Hinshelwood （LH） channel. There exists structural relaxation for Cu13 cluster in the reaction, which may influence the catalytic activity of cluster for the subsequent N2O decomposition. The core atom in the Cu13 cluster is substituted with the Fe, Co, or Ni to enhance structural stability and prevent from the obvious configuration relaxation in the reaction. Note that these bimetallic clusters are of icosahedra as the Cu13. They have activities for N2O dissociation along ER pathway and the heteroatorn in the cluster can prevent configuration from relaxation. Finally, the Ni@Cu12 cluster can be as a superior catalyst in a complete catalytic cycle via comparison in this study.
基金the National Natural Science Foundation of China(No.52000093)Yunnan Fundamental Research Projects(No.202101BE070001-001)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2019B03).
文摘NH_(3) in ambient air directly leads to an increase in the aerosol content in the air. These substances lead to the formation of haze to various environmental problems after atmospheric circulation and diffusion. Controlling NH_(3) emissions caused by ammonia escaping from mobile and industrial sources can effectively reduce the NH_(3) content in ambient air. Among the various NH_(3) removal methods, the selective catalytic oxygen method (NH_(3)-SCO) is committed to oxidizing NH_(3) to environmentally harmless H_(2)O and N_(2);therefore, it is the most valuable and ideal ammonia removal method. In this review, the characteristics of loaded and core-shell catalysts in NH_(3)-SCO have been reviewed in the context of catalyst structure-activity relationships, and the H_(2)O resistance and SO2 resistance of the catalysts are discussed in the context of practical application conditions. Then the effects of the valence state of the active center, oxygen species on the catalyst surface, dispersion of the active center and acidic sites on the catalyst performance are discussed comprehensively. Finally, the shortcomings of the existing catalysts are summarized and the catalyst development is discussed based on the existing studies.
文摘为了防止铁酸钴(Co Fe_(2)O_(4))纳米颗粒团聚,提高其对奥克托今(HMX)和哈托(TKX-50)的催化分解性能,采用类石墨氮化碳(g-C_(3)N_(4))作为Co Fe_(2)O_(4)纳米颗粒的分散剂载体,通过溶剂热法原位生长制备了Co Fe_(2)O_(4)/g-C_(3)N_(4)二元纳米复合材料,并利用X射线粉末衍射仪、扫描电子显微镜、傅立叶变换红外光谱仪以及差示扫描量热仪等研究了其组成、结构形貌及催化分解性能。结果表明,Co Fe_(2)O_(4)/g-C_(3)N_(4)复合材料形貌均匀密实,使HMX和TKX-50的热分解峰温分别降低了7.0℃和41.3℃,表观活化能分别降低了341.1 k J·mol^(-1)和21.0 k J·mol^(-1),同时增大了其放热量。残渣分析结果发现HMX几乎完全被催化分解,而TKX-50催化分解不彻底,其残渣和Co Fe_(2)O_(4)/g-C_(3)N_(4)形成了微米级块状混合物。
