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微量Co修饰的碳载超细Pt纳米粒子的制备及其在燃料电池氧还原催化中的应用(英文) 被引量:7
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作者 唐雪君 方达晖 +6 位作者 瞿丽娟 徐东彦 秦晓平 覃博文 宋微 邵志刚 衣宝廉 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第4期504-514,M0002,共12页
质子交换膜燃料电池(PEMFC)具有清洁、高效等优点,是一种理想的汽车动力电源.然而,由于其阴极氧还原反应(ORR)速率缓慢,需要使用大量的Pt基催化剂,导致燃料电池成本居高不下,严重制约了PEMFC的商业化发展.将Pt与过渡金属Fe, Co, Ni等形... 质子交换膜燃料电池(PEMFC)具有清洁、高效等优点,是一种理想的汽车动力电源.然而,由于其阴极氧还原反应(ORR)速率缓慢,需要使用大量的Pt基催化剂,导致燃料电池成本居高不下,严重制约了PEMFC的商业化发展.将Pt与过渡金属Fe, Co, Ni等形成合金,对表面Pt原子的几何结构和电子结构进行调变,可以有效提高催化剂的活性,实现Pt用量和燃料电池成本的降低.但是目前合金催化剂多采用溶剂热、浸渍-高温退火等制备方法,使用有毒有害试剂和难清洗的表面活性剂,且过程复杂、能耗高,不利于大规模化生产.此外,合金中过渡金属占比高,在燃料电池工况下,大量过渡金属溶解,加速了膜的降解,导致实际PEMFC性能的降低.对此,我们探索了一种简便有效的方法制备高活性、高稳定性的碳载Pt-Co催化剂.在没有添加表面活性剂的情况下,采用硼氢化钠辅助乙二醇还原法合成了具有超小尺寸和均匀分布的Pt-Co纳米颗粒,后续酸刻蚀处理去除不稳定的Co原子,重组双金属纳米颗粒的表面结构形成富Pt壳层,进一步提高了催化剂的活性和稳定性.通过电感耦合等离子体、X射线粉末衍射、透射电子显微镜、高分辨透射电子显微镜、高角环形暗场-扫描透射-元素分布及光电子能谱等物理表征证实了微量Co改性的碳载超细铂合金纳米颗粒的组成和结构.进一步对催化剂进行旋转圆盘电极和单电池测试,结果表明, Pt_(36)Co/C具有明显高于商业化Pt/C的有效电化学活性面积和电池性能.此外,加速衰减测试和衰减前后的电镜图片表明, Pt_(36)Co/C催化剂的稳定性相较于Pt/C亦有所增强.分析Pt-Co/C催化性能提高的原因,主要归于以下三点:(1)催化剂纳米颗粒在载体上分布均匀,且具有超小的粒径尺寸,提供了大量的三相反应界面位点;(2)双金属配体和电子效应的协同作用,降低了氧化物质在催化表面的吸附能力,加速了ORR的电催化动力学;(3)酸蚀刻导致的不稳定Co的溶解及催化剂表面结构的重排,形成了富Pt壳层结构,有利于提高催化剂的稳定性.这种简单有效的合金制备方法可以在电催化领域推广使用. 展开更多
关键词 质子交换膜燃料电池 氧还原反应 超细Pt纳米粒子 微量Co修饰 改进的乙二醇还原法 酸刻蚀
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Hydrogen generation from methanolysis of sodium borohydride over Co/Al_2O_3 catalyst 被引量:3
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作者 dongyan xu Lin Zhao +1 位作者 Ping Dai Shengfu Ji 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2012年第5期488-494,共7页
Co/Al2O3 catalyst is prepared with an impregnation-chemical reduction method and used to catalyze the methanolysis of sodium borohydride (NaBH 4) for hydrogen generation.At solution temperature of 0 C,the methanolys... Co/Al2O3 catalyst is prepared with an impregnation-chemical reduction method and used to catalyze the methanolysis of sodium borohydride (NaBH 4) for hydrogen generation.At solution temperature of 0 C,the methanolysis reaction can be effectively accelerated using Co/Al2O3 catalyst and provide a desirable hydrogen generation rate,which makes it suitable for applications under the circumstance of low environmental temperature.The byproduct of methanolysis reaction is analyzed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR).The characterization results indicate that methanol can be easily recovered after methanolysis reaction by hydrolysis of the methanolysis byproduct,NaB(OCH 3) 4.The catalytic activity of Co/Al2O3 towards NaBH 4 methanolysis can be further improved by appropriate calcination treatment.The catalytic methanolysis kinetics and catalyst reusability are also studied over the Co/Al2O3 catalyst calcined at the optimized temperature. 展开更多
关键词 hydrogen generation sodium borohydride METHANOLYSIS COBALT
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Ultrafine PdAg alloy nanoparticles anchored on NH2-functionalized 2D/2D TiO_(2) nanosheet/rGO composite as efficient and reusable catalyst for hydrogen release from additive-free formic acid at room temperature 被引量:1
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作者 Xi Zhao Ping Dai +3 位作者 dongyan xu xumei Tao Xien Liu Qingjie Ge 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第8期455-464,I0010,共11页
A 2 D-2 D titanium dioxide nanosheet-reduced graphene oxide(TNS-r GO)composite with better electronic conductivity and hydrophilicity was prepared by the hydrothermal method.The as-obtained TNS-r GO composite was furt... A 2 D-2 D titanium dioxide nanosheet-reduced graphene oxide(TNS-r GO)composite with better electronic conductivity and hydrophilicity was prepared by the hydrothermal method.The as-obtained TNS-r GO composite was further functionalized with 3-aminopropyltriethoxysilane(APTES)to provide a large amount of-NH2 groups on the surface for anchoring ultrafine Pd Ag alloy nanoparticles with an average particle size of 1.69 nm by a facile wet reduction approach.Benefiting from the combined effects of well-dispersed Pd Ag alloy nanoparticles,facilitated electron transfer from TNS-r GO to Pd,and increased electron density of active sites,the Pd8 Ag_(1)/NH_(2)-TNS-r GO catalyst exhibited excellent activity towards dehydrogenation of formic acid without adding any additives at 298 K,corresponding to an initial turn over frequency as high as 1090 h-1,which is much higher than that of most other state-of-theart catalysts. 展开更多
关键词 Formic acid DEHYDROGENATION TNS-rGO composite PdAg alloy Amine-functionalization
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伴有肛周疾病的炎症性肠病患者肛门功能及生活质量分析
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作者 王梦 徐东燕 +1 位作者 张晓雨 赵海剑 《中华消化病与影像杂志(电子版)》 2022年第4期224-227,共4页
目的分析肛周疾病对炎症性肠病(IBD)患者肛门直肠功能和生活质量的影响。方法回顾性分析2018年6月至2020年6月淮安市第二人民医院收治的伴有肛门不适的53例IBD患者(IBD组)。其中CD43例,UC10例。包括肛瘘35例,大便失禁15例,肛门纤维化8... 目的分析肛周疾病对炎症性肠病(IBD)患者肛门直肠功能和生活质量的影响。方法回顾性分析2018年6月至2020年6月淮安市第二人民医院收治的伴有肛门不适的53例IBD患者(IBD组)。其中CD43例,UC10例。包括肛瘘35例,大便失禁15例,肛门纤维化8例。选择同期来淮安市第二人民医院体检的健康人20名作为健康对照组。通过肛门直肠测压对IBD患者和健康对照组受试者肛门功能进行评估并进行比较。采用炎症性肠病患者生活质量量表(IBDQ)评分对IBD患者生活质量进行评估。结果IBD患者与健康对照组最大肛门静息压、最大挤压压、直肠容量感觉阈值、最大耐受容量、肛管抑制反射阳性水平差异均无统计学意义(P均>0.05)。大便失禁的IBD患者最大肛门静息压、IBDQ评分均低于非大便失禁的IBD患者,且差异均有统计学意义(P<0.05)。CD与UC患者IBDQ评分差异无统计学意义(P>0.05);大便失禁IBD患者IBDQ评分低于非大便失禁IBD患者,且差异有统计学意义(P<0.05)。结论合并肛周疾病的IBD患者肛门直肠功能受损,大便失禁的患者生活质量差。 展开更多
关键词 炎症性肠病 克罗恩病 溃疡性结肠炎症 肛周疾病 生活质量
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Efficient promotion of methane hydrate formation and elimination of foam generation using fluorinated surfactants
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作者 Quan CAO dongyan xu +2 位作者 Huanfei xu Shengjun LUO Rongbo GUO 《Frontiers in Energy》 SCIE CSCD 2020年第3期443-451,共9页
Methane hydrate preparation is an effective method to store and transport methane.In promoters to facilitate methane hydrate formation,homogeneous surfactant solutions,sodium dodecyl sulfate(SDS)in particular,are more... Methane hydrate preparation is an effective method to store and transport methane.In promoters to facilitate methane hydrate formation,homogeneous surfactant solutions,sodium dodecyl sulfate(SDS)in particular,are more favorable than heterogeneous particles,thanks to their faster reaction rate,more storage capacity,and higher stability.Foaming,however,could not be avoided during hydrate dissociation with the presence of SDS.This paper investigated the ability of five fluorinated surfactants:potassium perfluorobutane sulfonate(PBS),potassium perfluorohexyl sulfonate(PHS),potassium perfluorooctane sulfonate(POS),ammonium perfluorooctane sulfonate(AOS),and tetraethylammonium perfluorooctyl sulfonate(TOS)to promote methane hydrate formation.It was found that both PBS and PHS achieve a storage capacity of 150(V/V,the volume of methane that can be stored by one volume of water)within 30 min,more than that of SDS.Cationic ions and the carbon chain length were then discussed on their effects during the formation.It was concluded that PBS,PHS,and POS produced no foam during hydrate dissociation,making them promising promoters in large-scale application. 展开更多
关键词 methane hydrate fluorinated surfactants homogeneous promoter foam elimination stability
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