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Grain boundary engineering of CeO2 induced electron redistribution for dimethyl carbonate synthesis from CO2 认领 引用
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作者 Guoqiang Hou Di Xu +3 位作者 Haifeng Fan Yangyang Li Siyi Huang Mingyue Ding 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2026年第1期316-329,共14页
Direct synthesis of dimethyl carbonate(DMC)from CO2 is critical for achieving carbon neutrality,yet the sluggish formation and conversion of the key*CH₃OCOO intermediate-due to the difficulty of C-O coupling-limit ... Direct synthesis of dimethyl carbonate(DMC)from CO2 is critical for achieving carbon neutrality,yet the sluggish formation and conversion of the key*CH₃OCOO intermediate-due to the difficulty of C-O coupling-limit high DMC yields.Herein,we developed a boric acid-assisted recrystallization strategy to fabricate grain-boundary-rich CeO2 hollow nanospheres,which serve as an efficient catalyst for CO2 to DMC synthesis.The introduction of grain-boundary(GBs)induced the electron redistribution,which led a decrease in the electron density of bulk Ce ions and created a localized electron-rich region at homogeneous interface.This unique electronic landscape promoted reactive methoxy formation and stronger CO2 adsorption,thereby enabling more efficient coupling of*CH3O and*CO2 to form the*CH3OCOO.Concurrently,the enhanced CO2 adsorption facilitated the dissociation of*CH3OCOO and subsequent DMC formation.As a result,the 4%BCeO2-GBs achieved an advantageous DMC yield of 19.8 mmol/g.In the assistance of dehydrating agent,the catalyst delivered a remarkable 264.2 mmol/g DMC yield and 7.12%methanol conversion,which was 32 times higher than commercial CeO2.This study elucidated the intrinsic mechanisms governing*CH3OCOO intermediate behavior and offers valuable guidance for CO2 converting into high-value organic chemicals. 展开更多
关键词 Dimethyl carbonate synthesis CeO2 catalyst Grain boundary engineering Electron redistribution Reaction intermediates
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纳米CeO_2吸附剂的制备及对六价铬的吸附性能 认领 引用 被引量：9
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作者 张金洋 黄敏 +3 位作者 李琴 刘敏 付孝锦 雷光东 《人工晶体学报》 CAS CSCD 北大核心 2018年第8期1662-1669,共8页
吸附法是去除水中重金属离子的重要方法,开发新型吸附剂一直是研究热点。利用浸渍法和水热法制备了片状和无定形的纳米CeO_2吸附剂,探讨其对六价铬的吸附性能,分析pH、吸附时间、六价铬初始浓度等因素对其吸附性能的影响,并通过循环吸... 吸附法是去除水中重金属离子的重要方法,开发新型吸附剂一直是研究热点。利用浸渍法和水热法制备了片状和无定形的纳米CeO_2吸附剂,探讨其对六价铬的吸附性能,分析pH、吸附时间、六价铬初始浓度等因素对其吸附性能的影响,并通过循环吸附实验考察纳米CeO_2吸附剂的再生能力。结果表明:厚度30 nm、直径大小约为400nm的片状CeO_2吸附剂具有更强的吸附能力和更快的吸附速率,80 min时基本达到吸附平衡;两种吸附剂的最佳吸附pH为3;吸附动力学均符合伪二级动力学方程,Langmuir模型和Freundlich模型均能很好地拟合等温吸附过程,表明纳米CeO_2对六价铬的吸附以单层吸附为主。片状CeO_2四次吸附-解吸实验之后吸附率稍有下降,表明片状CeO_2吸附剂有较好的再生能力,因而,该片状CeO_2吸附剂适用于与酸性Cr(Ⅵ)废水的处理。 展开更多
关键词 片状CeO2 无定型CeO2 六价铬 吸附
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Catalytic Oxidative Properties and Characterization of CuO/CeO_2 Catalysts 认领 引用 被引量：8
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作者 蒋晓原 周仁贤 +2 位作者 袁骏 吕光烈 郑小明 《Journal of Rare Earths》 SCIE EI CAS 2003年第1期55-59,共5页
The oxidative properties and characterization of CuO, CeO 2 and CuO/CeO 2 cata lysts were examined by means of a CO micro-reactor GC system, TPR, XPS and X-r ay diffraction Rietveld methods. The results show that eith... The oxidative properties and characterization of CuO, CeO 2 and CuO/CeO 2 cata lysts were examined by means of a CO micro-reactor GC system, TPR, XPS and X-r ay diffraction Rietveld methods. The results show that either CuO or CeO 2 ac tivity is quite low for CO oxidation. However, when CuO and CeO 2 are mixed, the oxidative activity of the catalyst increases significantly, probably owing to the valency status of copper species (Cu 2+ and Cu+) on the CeO 2 surfa ce, the dispersion and reducibility. XPS surface analysis shows that CuO loading is very important in forming of either Cu 2+ or Cu+. Rietveld analysis s hows that some CuO, which has smaller ion radius than Ce 4+, enters the Ce O 2 lattice after CuO and CeO 2 are mixed. When the CuO loading reaches 5.0%, the size of CuO crystals is a minimum (6.1 nm) and the micro-strain value i s a maximum (2.86×10 -3), resulting in high surface energy and the best ac tivity for CO oxidation. 展开更多
关键词 physical chemistry CuO/CeO 2 catalysts CO micro-reactor GC system rare earths
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CeO2对激光熔覆TiCp/Ni基复合涂层的影响 认领 引用 被引量：12
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作者 许伯藩 李安敏 +1 位作者 潘应君 张细菊 《热加工工艺》 北大核心 2002年第6期10-12,共3页
利用5kWCO2激光器在A3钢表面激光熔覆添加不同CeO2含量的TiCp/Ni复合涂层。研究了稀土氧化物对激光熔覆金属陶瓷复合涂层的组织结构与性能的影响。结果表明,预涂覆复合合金粉末中添加0.4%CeO2能减少涂层的气孔、疏松,使涂层的组织致密... 利用5kWCO2激光器在A3钢表面激光熔覆添加不同CeO2含量的TiCp/Ni复合涂层。研究了稀土氧化物对激光熔覆金属陶瓷复合涂层的组织结构与性能的影响。结果表明,预涂覆复合合金粉末中添加0.4%CeO2能减少涂层的气孔、疏松,使涂层的组织致密及涂层中TiC颗粒细小光滑,分布均匀,复合涂层的耐磨性与耐蚀性得到显著提高。 展开更多
关键词 激光熔覆 稀土氧化物CeO2 金属陶瓷涂层 耐磨性 耐蚀性
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CeO_2/ACF的低温SCR烟气脱硝性能研究 认领 引用 被引量：58
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作者 沈伯雄 郭宾彬 +2 位作者 史展亮 吴春飞 梁材 《燃料化学学报》 北大核心 2007年第1期125-128,共4页
The selective catalytic reduction(SCR) of NOx using MnOx and CeO2 supported on viscose-based active carbon fibers(ACF) at 120 ℃～270 ℃ relatively lower than the temperature when using V2O5/TiO2-anatase catalyst was ... The selective catalytic reduction(SCR) of NOx using MnOx and CeO2 supported on viscose-based active carbon fibers(ACF) at 120 ℃～270 ℃ relatively lower than the temperature when using V2O5/TiO2-anatase catalyst was studied.As a result,CeO2/ACF shows a better catalysis than MNOx/ACF,which is not affected by the reaction temperature. NO conversion of 85% is reached with the 10%-CeO2/ACF catalyst at the whole temperature window.Furthermore,a series of MnOx-CeO2/ACF composite catalysts were studied.The results show that the loading method of catalyst affects its activity. 展开更多
关键词 低温SCR CeO2 ACF
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CeO_2对激光熔敷合金层组织和腐蚀磨损性能的影响 认领 引用 被引量：3
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作者 王顺兴 郑世安 +2 位作者 赵涛 董企铭 张一民 《钢铁研究学报》 CAS 北大核心 2000年第3期47-50,共4页
用 X射线衍射仪、SEM、TEM和电子探针研究了稀土氧化物 Ce O2 对 Ni6 0 - WC激光熔敷层的相结构、显微组织以及腐蚀磨损性能的影响。试验结果表明 ,Ni6 0 +2 0 % WC+0 .5 % Ce O2 熔敷层的抗腐蚀磨损性能最好。
关键词 激光熔敷层 CeO2 显微组织 腐蚀磨损性能
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纳米燃油添加剂CeO_2提高柴油燃烧效率减少排放 认领 引用 被引量：18
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作者 邬齐敏 孙平 +2 位作者 梅德清 孙柱 季燕平 《农业工程学报》 EI CAS CSCD 北大核心 2013年第9期64-69,共6页
研制新型高效燃油添加剂已成为控制发动机燃烧与排放的重要课题,纳米CeO2颗粒因其独特物理化学性质使其在催化燃烧和尾气净化领域具有独特的作用。通过向柴油中添加微量纳米CeO2颗粒,配制成质量分数为50mg/L和100mg/L的CeO2-柴油混合燃... 研制新型高效燃油添加剂已成为控制发动机燃烧与排放的重要课题,纳米CeO2颗粒因其独特物理化学性质使其在催化燃烧和尾气净化领域具有独特的作用。通过向柴油中添加微量纳米CeO2颗粒,配制成质量分数为50mg/L和100mg/L的CeO2-柴油混合燃料,标记为D50C和D100C,以柴油(Diesel)为参照,并在186FA柴油机上对比研究了这3种燃料的燃烧与排放性能。结果表明:通过加入表面活性剂CTAB和超声处理物理化学方法可使纳米CeO2颗粒稳定悬浮于柴油中。标定转速全负荷下发动机燃用D50C和D100C后缸内压力峰值、压升率峰值和放热率峰值都有略微增加的趋势,而其对应的曲轴转角相应提前,滞燃期分别相应缩短1o和2o曲轴转角。发动机燃油D50C和D100C后燃油消耗率略有降低,有效热效率有所增加。纳米CeO2颗粒添加至柴油中4种常规污染物都有不同程度的降低,且随其添加量增加越发明显。相比于纯柴油,标定转速全负荷下,D50C和D100C的比油耗分别降低约1.6%和2.3%,有效热效率分别增加约1.7%和2.3%。D50C和D100C的CO、HC、NOx和烟度排放平均分别降低3.4%和6.5%、15.1%和18.4%、2.4%和5.4%、4.0%和7.8%。D50C和D100C混合燃料的成本分别比柴油上升约0.8%和1.6%。综合来看,微量添加纳米CeO2颗粒可在略微增加燃油价格的前提下,即可实现发动机的高效燃烧与节能减排,因而是一种性能优良的燃油添加剂。 展开更多
关键词 柴油机 燃烧 排放 CeO2
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湿式氧化吡虫啉农药生产废水的MnOx-CeO2催化剂性能研究 认领 引用 被引量：13
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作者 赵彬侠 张小里 +2 位作者 李红亚 刘林学 金奇庭 《高等学校化学学报》 SCIE CAS 北大核心 2009年第5期965-970,共6页
采用共沉淀法制备了用于湿式氧化吡虫啉农药废水的MnOx-CeO2系列催化剂,利用比表面测定仪(BET),X射线衍谢仪(XRD)和X射线光电子能谱(XPS)等对其进行了表征,并研究了不同Mn/(Mn+Ce)摩尔比对催化剂表面形态的影响以及催化剂表面形态与活... 采用共沉淀法制备了用于湿式氧化吡虫啉农药废水的MnOx-CeO2系列催化剂,利用比表面测定仪(BET),X射线衍谢仪(XRD)和X射线光电子能谱(XPS)等对其进行了表征,并研究了不同Mn/(Mn+Ce)摩尔比对催化剂表面形态的影响以及催化剂表面形态与活性之间的关系.BET和XRD表征结果表明,Mn/(Mn+Ce)摩尔比为0.6时,催化剂晶粒尺寸最小,比表面积最大.XRD和XPS表征结果显示,Mn和Ce氧化物之间存在明显的相互作用,催化剂表面Mn的氧化态和化学需氧量(COD)随着组成的变化而变化,当Mn/(Mn+Ce)摩尔比为0.7时,催化剂表面出现高价锰氧化物,而且其化学吸附氧最多.用Mn/(Mn+Ce)摩尔比为0.7的MnOx-CeO2催化湿式氧化吡虫啉农药废水时,当催化剂用量为4 g/L,反应温度190℃,进水pH为7.0,氧分压1.6 MPa,搅拌速度500 r/min,反应60 min时,COD去除率最大为89.3%. 展开更多
关键词 催化湿式氧化 农药废水 MnOx-CeO2 CeO2
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超细CeO_2粉体的制备及其紫外线吸收性能 认领 引用 被引量：35
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作者 朱兆武 龙志奇 +2 位作者 崔大立 张顺利 张国成 《中国有色金属学报》 EI CAS 北大核心 2005年第3期435-440,共6页
用碳酸氢铵作沉淀剂通过添加NH4NO3和(NH4)2CO4两种不同的试剂制备了超细CeO2粉体.采用X射线衍射、BET和激光散射的方法研究了不同灼烧温度下粉体粒径的变化规律,并研究了粉体粒径对紫外线吸收的影响.结果表明:NH4NO3和(NH4)2CO4作为添... 用碳酸氢铵作沉淀剂通过添加NH4NO3和(NH4)2CO4两种不同的试剂制备了超细CeO2粉体.采用X射线衍射、BET和激光散射的方法研究了不同灼烧温度下粉体粒径的变化规律,并研究了粉体粒径对紫外线吸收的影响.结果表明:NH4NO3和(NH4)2CO4作为添加剂可以制得一次粒径在10～100 nm的纳米粉体,团聚粒径在200～300 nm分散性好的超细CeO2粉体.X射线衍射和BET测得的一次粒径随灼烧温度升高呈明显增大的趋势,激光散射测得的团聚粒径随灼烧温度变化不明显.CeO2粉体分散在去离子水中的吸收光谱研究表明,粉体一次粒径大小对光的吸收效果有明显影响,粒径小,紫外线吸收效果好,可见光穿透性强,粒径增大,粉体将失去紫外线吸收效果,紫外吸收受粉体的团聚粒径影响不大. 展开更多
关键词 超细CeO2粉体 制备 紫外吸收
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活性炭的预处理对CeO2/AC催化剂NH3选择性催化还原NOx性能的影响 认领 引用 被引量：6
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作者 黄利华 李雪 陈耀强 《新型炭材料》 CSCD 北大核心 2018年第3期237-244,共8页
为了改善活性炭(AC)负载的CeO_2基催化剂的脱硝性能,采用空气热氧化或硝酸对活性炭进行预处理,考察了预处理方式对其负载的CeO_2基催化剂氨选择性催化还原(NH_3-SCR)NO_x反应性能的影响。对预处理后的活性炭及其负载的CeO_2基催化剂进... 为了改善活性炭(AC)负载的CeO_2基催化剂的脱硝性能,采用空气热氧化或硝酸对活性炭进行预处理,考察了预处理方式对其负载的CeO_2基催化剂氨选择性催化还原(NH_3-SCR)NO_x反应性能的影响。对预处理后的活性炭及其负载的CeO_2基催化剂进行了红外光谱(FTIR)、NH_3程序升温脱附(NH_3-TPD)、N_2吸附-脱附、X射线衍射(XRD)及H_2-TPR等表征。结果表明:硝酸预处理显著增加了活性炭表面含氧官能团、增强了表面酸性,提高了其负载的CeO_2基催化剂的氧化还原性能,促进了催化剂表面NH_3的吸附和活化,使催化剂表现催化优异的NH_3-SCR脱硝性能。该催化剂对NO_x的起燃温度和完全转化温度分别为75℃和190℃,显著优于空气热氧化处理的活性炭制备的催化剂,但H_2O易导致催化剂活性下降。 展开更多
关键词 活性炭 预处理 CeO2 NH3选择性催化还原 NOx
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CeO_2纳米管的水热合成、表征及性能研究 认领 引用 被引量：17
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作者 赵晓兵 游静 +1 位作者 陆晓旺 陈志刚 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2011年第2期159-164,共6页
以P123为表面活性剂,采用水热法合成CeO2纳米管.研究反应时间、反应温度、表面活性剂浓度对CeO2纳米管形成的影响规律.采用TEM、XRD、N2吸脱附仪对样品的微观结构进行表征.并考察CeO2纳米管对亚甲基蓝溶液的催化性能.结果表明,当反应时... 以P123为表面活性剂,采用水热法合成CeO2纳米管.研究反应时间、反应温度、表面活性剂浓度对CeO2纳米管形成的影响规律.采用TEM、XRD、N2吸脱附仪对样品的微观结构进行表征.并考察CeO2纳米管对亚甲基蓝溶液的催化性能.结果表明,当反应时间为72 h、反应温度为160℃、n（P123）：n（CeCl3.7H2O）=1：5时,可制备出单晶结构的CeO2纳米管.所制备的CeO2纳米管外径为40~60nm,内径为20 nm左右,长度为500~1000nm.CeO2纳米管是由Ce（OH）3晶种的溶解再结晶-异向生长-自我卷曲形成的.相对于CeO2纳米颗粒和CeO2纳米棒,CeO2纳米管对亚甲基蓝染料的脱色率有明显提高.这与CeO2纳米管孔道的吸附作用,暴露的高反应活性面（110）和表面有大量缺陷有关. 展开更多
关键词 水热法 CeO2纳米管 催化
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气氛氧压对脉冲激光法制备的CeO_2/Si薄膜的结晶取向的影响 认领 引用 被引量：3
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作者 李美亚 王忠烈 +3 位作者 范守善 赵清太 熊光成 林揆训 《功能材料》 EI CAS 北大核心 2000年第2期159-161,共3页
用脉冲激光镀膜法 ,在不同的温度和氧压条件下 ,在Si(10 0 )片上制备了一系列的CeO2 膜。X射线衍射分析表明 ,在较低的氧压下生长的CeO2 膜为 (111)取向 ,在较高的氧压下生长的膜则为 (10 0 )取向。研究表明 ,CeO2 膜的取向对氧压显示... 用脉冲激光镀膜法 ,在不同的温度和氧压条件下 ,在Si(10 0 )片上制备了一系列的CeO2 膜。X射线衍射分析表明 ,在较低的氧压下生长的CeO2 膜为 (111)取向 ,在较高的氧压下生长的膜则为 (10 0 )取向。研究表明 ,CeO2 膜的取向对氧压显示了独特的依赖性 ,氧压对控制膜的结晶取向具有十分重要的作用。讨论了氧压对CeO2 薄膜结晶取向影响的可能机理。 展开更多
关键词 CeO2薄膜 结晶取向 脉冲激光沉积 气氛氧压
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Effect of decomposition of catalyst precursor on Ni/CeO_2 activity for CO methanation 认领 引用 被引量：12
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作者 Xiaoshan Zhang Ning Rui +2 位作者 Xinyu Jia Xue Hu Chang-jun Liu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第4期495-503,M0002,共9页
CO methanation on Ni/CeO2 has recently received increasing attention.However,the low-temperature activity and carbon resistance of Ni/CeO2 still need to be improved.In this study,plasma decomposition of nickel nitrate... CO methanation on Ni/CeO2 has recently received increasing attention.However,the low-temperature activity and carbon resistance of Ni/CeO2 still need to be improved.In this study,plasma decomposition of nickel nitrate was performed at ca.150℃ and atmospheric pressure.This was followed by hydrogen reduction at 500 ℃ in the absence of plasma,and a highly dispersed Ni/CeO2 catalyst was obtained with improved CO adsorption and enhanced metal-support interaction.The plasma-decomposed catalyst showed significantly improved low-temperature activity with high methane selectivity(up to 100%)and enhanced carbon resistance for CO methanation.For example,at 250 ℃,the plasma-decomposed catalyst showed a CO conversion of 96.8% with high methane selectivity(almost 100%),whereas the CO conversion was only 14.7% for a thermally decomposed catalyst. 展开更多
关键词 Nickel CeO2 Carbon monoxide Syngas Methanation Plasma
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纳米CeO_2的制备技术及应用 认领 引用 被引量：34
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作者 宋晓岚 王海波 +1 位作者 吴雪兰 邱冠周 《稀土》 CAS 北大核心 2004年第3期55-61,70,共7页
综述并评价了目前国内外有关纳米CeO2的多种制备方法及其特点。从CeO2的结构特点和功能特性出发着重介绍了纳米CeO2在汽车尾气净化、燃料电池、电化学反应、化学机械抛光及金属表面涂层等若干高科技领域中的应用研究进展,并提出了纳米C... 综述并评价了目前国内外有关纳米CeO2的多种制备方法及其特点。从CeO2的结构特点和功能特性出发着重介绍了纳米CeO2在汽车尾气净化、燃料电池、电化学反应、化学机械抛光及金属表面涂层等若干高科技领域中的应用研究进展,并提出了纳米CeO2研究的发展方向,为进一步深入研究和开发高性能新型CeO2功能纳米材料提供参考和借鉴。 展开更多
关键词 纳米CeO2 制备 应用 研究发展
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Understanding morphology-dependent Cu Ox-CeO2 interactions from the very beginning 认领 引用 被引量：9
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作者 Yuxian Gao Zhenhua Zhang +1 位作者 Zhaorui Li Weixin Huang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第6期1006-1016,共11页
Elucidation of the CuOx-CeO2 interactions is of great interest and importance in understanding complex CuOx-CeO2 interfacial catalysis in various reactions. In the present work, we have investigated structures and cat... Elucidation of the CuOx-CeO2 interactions is of great interest and importance in understanding complex CuOx-CeO2 interfacial catalysis in various reactions. In the present work, we have investigated structures and catalytic activity in CO oxidation of CuOx species on CeO2 rods, cubes and polyhedra predominantly exposing {110}+{100}, {100} and {111} facets by the incipient wetness impregnation method with the lowest Cu loading of 0.025%. The structural evolution of CuOx species was found to depend on both the Cu loading and the CeO2 morphology. As the Cu loading increases, CuOx species are deposited preferentially on the surface defect of CeO2 and then aggregate and grow, accompanied by the formation of isolated Cu ions, CuOx clusters strongly/weakly interacting with the CeO2, highly dispersed Cu O nanoparticles, and large Cu O nanoparticles. The isolated Cu^+ species and CuOx clusters weakly interacting with the CeO2 were observed mainly on the O-terminated CeO2{100} facets. Meanwhile, more Cu(I) species are stabilized during CO reduction processes in CuOx/c-CeO2 catalysts than in CuOx-CeO2 and CuOx/p-CeO2 catalysts. The catalytic activities of various CuOx/CeO2 catalysts in CO oxidation vary with both the CuOx species and the CeO2 morphology. These results comprehensively elucidate the CuOx-CeO2 interactions and exemplify their morphology-dependence. 展开更多
关键词 CeO2 nanocrystals Cu Ox/CeO2 catalysts Metal-support interactions CO oxidation Morphology effect
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Structure and oxygen storage capacity of Pd/Pr/CeO_2-ZrO_2 catalyst:effects of impregnated praseodymia 认领 引用 被引量：11
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作者 冉锐 张宏伟 +2 位作者 吴晓东 樊俊 翁端 《Journal of Rare Earths》 SCIE EI CAS CSCD 2014年第2期108-116,共9页
Praseodymium （Pr） was impregnated to CeO2-ZrO2 solid solution by an impregnation method. The as-obtained Pr modi- fied CeO2-ZrO2 was impregnated with 1 wt.% Pd to prepare the catalysts. The structure and reducibilit... Praseodymium （Pr） was impregnated to CeO2-ZrO2 solid solution by an impregnation method. The as-obtained Pr modi- fied CeO2-ZrO2 was impregnated with 1 wt.% Pd to prepare the catalysts. The structure and reducibility of the fresh and hydrother- really aged catalysts were characterized by X-ray diffraction （XRD）, Raman, X-ray photoelectron spectroscopy （XPS）, CO chemi- sorption and H2 temperature-programmed reduction （H2-TPR）. The oxygen storage capacity （OSC） was evaluated with CO serving as probe gas. Effects of impregnated Pr on the structure and oxygen storage capacity of catalysts were investigated. The results showed that the aged Pr-impregnated samples had much higher OSC and better reducibility than the unmodified ones. The scheme of structural evolutions of the catalysts with and without Pr was also established. Partial of the impregnated Pr diffused into the bulk of CeO2-ZrO2 during ageing, which inhibited the sintering, and increased the amount of oxygen vacancies in CeO2-ZrO2 support. Furthermore, those impregnated Pr species which covered on the surface of the support obstructed the strong metal-support interaction between Pd and Ce so as to reduce the encapsulation of Pd as well as the back spill-over of the oxygen during the catalytic process. 展开更多
关键词 CeO2-ZrO2 praseodymia sintering covering oxygen storage capacity rare earths
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Preparation, Characterization of CuO/CeO_2 and Cu/CeO_2 Catalysts and Their Applications in Low-Temperature CO Oxidation 认领 引用 被引量：9
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作者 郑修成 韩东战 +4 位作者 王淑萍 张守民 王淑荣 黄唯平 吴世华 《Journal of Rare Earths》 SCIE EI CAS 2005年第1期47-51,共5页
CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were ... CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were examined by means of a microreactor-GC system, HRTEM, XRD, TPR and XPS techniques. The results show that CuO has not catalytic activity and the activity of CeO2 is quite low for CO oxidation. However, the catalytic activity of CuO/CeO2 and Cu/ CeO2 catalysts increases significantly. Furthermore, the activity of CuO/CeO2 is higher than that of Cu/CeO2 catalysts. 展开更多
关键词 catalytic chemistry CuO/CeO2 catalysts Cu/CeO2 catalysts carbon monoxide oxidation rare earths
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CeO_2@Au核壳结构纳米粒子的合成与性质研究 认领 引用 被引量：6
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作者 杨晓峰 董相廷 +2 位作者 黄磊 王进贤 刘桂霞 《中国稀土学报》 EI CAS 北大核心 2008年第6期683-688,共6页
采用沉淀法制备了球形CeO2纳米粒子,将其作为核粒子溶液,然后向其中滴加四氯合金酸溶液,在CeO2胶体表面利用柠檬酸钠还原[AuCl4]-离子,得到了CeO2@Au核壳结构纳米粒子。TEM分析表明,CeO2纳米粒子分散效果好,粒径为5 nm;CeO2@Au核壳粒子... 采用沉淀法制备了球形CeO2纳米粒子,将其作为核粒子溶液,然后向其中滴加四氯合金酸溶液,在CeO2胶体表面利用柠檬酸钠还原[AuCl4]-离子,得到了CeO2@Au核壳结构纳米粒子。TEM分析表明,CeO2纳米粒子分散效果好,粒径为5 nm;CeO2@Au核壳粒子为球形,无团聚,平均粒径为15 nm。XRD分析表明,CeO2@Au核壳粒子为晶型结构,属于立方晶系,CeO2空间群为O5H-FM3M,Au的空间群为Fm-3m。UV-vis分析发现,CeO2@Au核壳粒子在300和520 nm处呈现出两个比较强的吸收峰,分别对应于CeO2胶体溶液的吸收峰和金粒子的表面等离子共振吸收峰。EDS分析了核壳结构CeO2@Au纳米粒子中存在Ce,O和Au 3种元素。XPS分析表明,Ce3d3/2和Au4f电子结合能与标准结合能相比发生了变化,说明CeO2与Au之间存在着相互作用。 展开更多
关键词 核壳纳米粒子 纳米粒子 CeO2 CeO2@Au Au 稀土
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Promoting effect of microwave irradiation on CeO2-TiO2 catalyst for selective catalytic reduction of NO by NH3 认领 引用 被引量：20
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作者 Jie Cheng Liyun Song +5 位作者 Rui Wu Shining Li Yanming Sun Hongtai Zhu Wenge Qiu Hong He 《Journal of Rare Earths》 SCIE EI CAS CSCD 2020年第1期59-69,共11页
In this work we prepared several CeO2-TiO2 catalysts for the NH3-SCR reactionusing co-precipitation with assistance of microwave irradiation.The catalytic NH3-SCR activities over CeO2-TiO2 catalysts at low temperature... In this work we prepared several CeO2-TiO2 catalysts for the NH3-SCR reactionusing co-precipitation with assistance of microwave irradiation.The catalytic NH3-SCR activities over CeO2-TiO2 catalysts at low temperatures are largely enhanced by the treatment of microwave irradiation,the operation temperature window is also broadened.For better understanding the promotion mechanism,the catalyst prepared by conventional co-precipitation with and without microwave irradiation treatment was characterized with H2-TPR,NH3-TPD,XPS,XRD and BET.Microwave irradiation treatment accelerates the crystallite rate of CeO2-TiO2 catalysts,and greatly enlarges their surface area by adjusting their microstructures.The resistance to SO2 and H2O is also improved via regulating the hierarchical pore structure by the microwave irradiation.Microwave irradiation treatment can also improve the redox property and increase the acid sites over the catalyst surfaces.The result of in situ DRIFTS suggests that the microwave irradiation treatment generates more Br?nsted acid sites on CeO2-TiO2-2 h catalyst,helpful in SCR reactions.XPS results show that after microwave irradiation on the CeO2-TiO2 catalysts,the surface demonstrates an elevated concentration of chemisorbed oxygen,consequently leading to better oxidation of NO to NO2.Additionally,the molar ratio of Ce3+/Ce4+has been elevated after being treated by microwave irradiation,a vital factor in enhancing the NH3-SCR activities. 展开更多
关键词 SCR catalyst NH3-SCR Low temperature CeO2-TiO2 Microwave irradiation Rare earths
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Roles of Lewis and Brnsted acid sites in NO reduction with ammonia on CeO_2-ZrO_2-NiO-SO_42- catalyst 认领 引用 被引量：14
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作者 司知蠢 翁端 +1 位作者 吴晓东 江洋 《Journal of Rare Earths》 SCIE EI CAS 2010年第5期727-731,共5页
Nickel and sulfate co-modified CeO2-ZrO2 catalysts were prepared by sol-gel method. The catalysts were characterized by XRD, FTIR, XPS, NH3 chemisorption and NH3-SCR activity tests. The results showed that the enhance... Nickel and sulfate co-modified CeO2-ZrO2 catalysts were prepared by sol-gel method. The catalysts were characterized by XRD, FTIR, XPS, NH3 chemisorption and NH3-SCR activity tests. The results showed that the enhanced acidity of CeO2-ZrO2 catalysts by nickel and sulfate co-modification was responsible for the broadened temperature window and improved the selectivity to N2 in NH3-SCR deNOx. The introduction of nickel to CeO2-ZrO2 solid solutions resulted in more Ce3+ on surface of catalyst, leading to an in... 展开更多
关键词 CeO2-ZrO2 nickel sulfate acid sites rare earths
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