共查询到20条相似文献，搜索用时 15 毫秒
1.
《化学学报》2012,70(5)
采用微湿含浸法制备了有序中孔炭/四氧化三铁磁性材料.采用透射电镜和X射线衍射对复合材料进行了表征.将血红蛋白（Hb）固定于材料表面,对其直接电化学行为进行了研究,结果表明Hb在该材料内仍保持了其生物活性,在pH=7.0的PBS缓冲液中,血红蛋白表现出一对峰形良好的准可逆氧化还原峰,为Hb的Fe（Ⅲ）/Fe（Ⅱ）电对的特征峰,求出式电位E0＇为-0.306 V,电子转移数为n=1.226,电荷传递系数为α=0.51,表观异相电子转移速率常数为KS=0.0144s-1.在3.00×10-6到1.50×10-4mol/L浓度范围内,血红蛋白的浓度与其响应电流呈良好的线性关系,线性相关系数为R=0.9924,最低检测限为0.270×10-6mol/L. 相似文献
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Prof. Li Wang Jiahua Zhao Prof. Pengfei Zhang Dr. Shize Yang Prof. Wangcheng Zhan Prof. Sheng Dai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8494-8498
Ruthenium (Ru)@Ordered mesoporous carbon (OMC) is a key catalyst in fine-chemical production. In general, the OMC support is prepared by a wet self-assembly requiring excessive solvent, toxic phenol–aldehyde precursors and a long reaction time, followed by post-immobilization to load Ru species. Herein, we wish to report a solid-state, rapid, and green strategy for the synthesis of Ru@OMC with biomass tannin as the precursor. The chemistry essence of this strategy lies in the mechanical-force-driven assembly, during which tannin-metal (Zn2+ and Ru3+) coordination polymerization and hydrogen-bonding interactions between tannin-block copolymer (PEO-PPO-PEO, F127) simultaneously occur. After thermal treatment, Ru@OMC catalysts with mesoporous channels, narrow pore-size distribution (≈7 nm), and high surface area (up to 779 m2 g−1) were directed by F127 micelles. Meanwhile, the Zn2+ ions dilute Ru3+ and avoid the sintering of Ru species, resulting in Ru clusters around 1.4–1.7 nm during carbonization (800 °C). Moreover, the Ru@OMC catalyst afforded a good activity (TOF: up to 4170 h−1) in the selective oxidation of benzyl alcohol to benzaldehyde by molecular oxygen. 相似文献
3.
采用微湿含浸法制备了有序中孔炭/四氧化三铁磁性材料.采用透射电镜和X射线衍射对复合材料进行了表征.将血红蛋白(Hb)固定于材料表面,对其直接电化学行为进行了研究,结果表明Hb在该材料内仍保持了其生物活性,在pH=7.0的PBS缓冲液中,血红蛋白表现出一对峰形良好的准可逆氧化还原峰,为Hb的Fe(Ⅲ)/Fe(Ⅱ)电对的特征峰,求出式电位E0’为-0.306 V,电子转移数为n=1.226,电荷传递系数为α=0.51,表观异相电子转移速率常数为KS=0.0144s-1.在3.00×10-6到1.50×10-4mol/L浓度范围内,血红蛋白的浓度与其响应电流呈良好的线性关系,线性相关系数为R=0.9924,最低检测限为0.270×10-6mol/L. 相似文献
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Dr. Diganta Saikia Dr. Juti Rani Deka Cheng-Wei Lin Yuan-Hung Lai Yu-Hao Zeng Po-Hung Chen Prof. Hsien-Ming Kao Prof. Yung-Chin Yang 《ChemSusChem》2020,13(11):2952-2965
Ultrafine CoO particles immobilized into the mesopores of three-dimensional cubic bimodal ordered mesoporous carbon CMK-9 is successfully prepared by using a combination of nanocasting and wet-impregnation methods. It is found that the cubic bimodal interconnected mesoporous framework of CMK-9 plays a crucial role in achieving the excellent electrochemical performances by assisting the rapid mass and charge transfer. Among the prepared nanocomposites, CoO(10)@CMK-9 delivers a discharge capacity of 830 mAh g−1 after 200 cycles at a current density of 100 mA g−1 in lithium-ion batteries. At a higher current density of 1000 mA g−1, the anode presents an outstanding discharge capacity of 636 mAh g−1 after 200 cycles. In sodium-ion batteries, the anode provides a discharge capacity of 296 mAh g−1 after 250 cycles at a current density of 100 mA g−1. The remarkable performances of CoO(10)@CMK-9 demonstrate the promising potentials of the nanocomposite as the anode for rechargeable batteries. 相似文献
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采用软模板法制备了氮化钨-钨/掺氮有序介孔碳复合材料(WN-W/NOMC),作为一种高比表面积且价格低廉的阴极氧还原反应催化剂。通过适量添加尿素来改变复合材料中的氮含量,在掺氮量为7%(w/w)时,实验发现材料能够保持完整有序介孔结构,测试其比表面积高达835 m~2·g~(-1),透射电子显微镜(TEM)测试结果显示其催化颗粒均匀地分散在氮掺杂有序介孔碳载体上。在O_2饱和的0.1 mol·L~(-1 )KOH溶液中测试了材料的氧还原催化性能(ORR),显示其起始电位为0.87 V(vs RHE),极限电流密度为4.49 mA·cm~(-2),氧还原反应的转移电子数为3.4,接近于20%(w/w)商业Pt/C的3.8,说明该材料表现出近似4电子的氧还原反应途径。研究结果表明,WN-W/NOMC的催化性能虽然稍弱于商业铂碳(0.99 V,5.1 mA·cm~(-2)),但其具有远超铂碳的循环稳定性和耐甲醇毒化能力。 相似文献
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燃料电池中贵金属铂的大量使用是阻碍其发展的关键因素,亟需探索高效廉价的替代型电催化剂.在目前的替代型非贵金属催化剂研究中,氮杂炭材料是一类氧还原反应催化活性最好、成本最低廉的催化剂,被认为是最有可能取代Pt催化剂而获得实际应用的催化剂.氮杂有序介孔炭材料因具有极高的比表面积和规整的孔道结构,可实现活性位点的密集组装与反应物料的快速传输,受到研究者的广泛关注.本文分别以苯胺、吡咯和邻菲罗啉为含氮前驱体,介孔分子筛SBA-15为硬模板,采用纳米浇铸法成功制备了具有高比表面积的氮杂有序介孔炭材料,系统研究了不同含氮前驱体对氮杂有序介孔炭材料的影响.采用氮气吸附-脱附等温线、透射电子显微镜(TEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)等方法研究了氮杂有序介孔炭的组成与结构,采用循环伏安法(CV)以及线性扫描伏安法(LSV)等手段考察了其电化学行为与氧还原反应极化性能.氮气吸附-脱附等温线结果表明,采用三种不同含氮前驱体制备的氮杂炭材料都对应Ⅳ型吸脱附等温线以及H4型滞后环,表明所制备的氮杂炭材料具有介孔结构.由TEM可以清楚地观察到氮杂炭材料已经成功地反转了SBA-15模板的孔道结构.同时发现,含氮前驱体对氮杂炭材料的比表面积和孔结构产生较大影响:以吡咯和邻菲罗啉为前驱体制备的炭材料C-PY-900和C-Phen-900的比表面积较高,分别为765和746 m2/g,而以苯胺为前驱体制备的炭材料C-PA-900比表面积较小(569 m2/g);三种炭材料平均孔径大小顺序为C-Phen-900 (3.7 nm)＜ C-PY-900 (5.0 nm)＜ C-PA-900 (5.9 nm),这是由于不同含氮前驱体在高温焙烧过程中热分解行为不同所致.XRD结果发现,含氮前驱体对氮杂炭材料的晶型基本没有影响,均为无定形碳.XPS结果表明,采用苯胺、吡咯以及林菲啰啉为前驱体制备的氮杂炭材料中氮含量基本相同,分别为3.13 at％,3.32 at％和3.33 at％,说明在相同热解条件下材料中的氮含量基本不受前驱体的影响,但不同配位环境的氮含量以及氮活化碳原子的含量却有较大差异,其氮活化碳原子的相对含量分别为15.60％,19.87％和23.04％.电化学测试结果表明,三种氮杂介孔炭材料的氧还原反应电催化活性顺序为C-PA-900＜C-PY-900＜C-Phen-900,其H2O2产率低于30％,说明氧还原反应经历4电子转移路径.在碱性条件下,所制氮杂有序介孔炭材料C-PY-900和C-Phen-900表现出较商品Pt/C催化剂更加优异的氧还原反应电催化性能.综上可见,通过改变含氮前驱体的类型可以有效调变氮杂炭材料的比表面积、孔道结构以及N 1s与C 1s化学态,从而调控氧还原反应活性,本文不仅制备出高活性的非贵金属氧还原电催化剂,同时也为高活性炭基电催化剂的可控制备提供了思路. 相似文献
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Dr. Zelong Li Dr. Guanglan Li Prof. Luhua Jiang Jinlei Li Prof. Gongquan Sun Prof. Chungu Xia Prof. Fuwei Li 《Angewandte Chemie (International ed. in English)》2015,54(5):1494-1498
A ferrocene‐based ionic liquid (Fe‐IL) is used as a metal‐containing feedstock with a nitrogen‐enriched ionic liquid (N‐IL) as a compatible nitrogen content modulator to prepare a novel type of non‐precious‐metal–nitrogen–carbon (M‐N‐C) catalysts, which feature ordered mesoporous structure consisting of uniform iron oxide nanoparticles embedded into N‐enriched carbons. The catalyst Fe10@NOMC exhibits comparable catalytic activity but superior long‐term stability to 20 wt % Pt/C for ORR with four‐electron transfer pathway under alkaline conditions. Such outstanding catalytic performance is ascribed to the populated Fe (Fe3O4) and N (N2) active sites with synergetic chemical coupling as well as the ordered mesoporous structure and high surface area endowed by both the versatile precursors and the synthetic strategy, which also open new avenues for the development of M‐N‐C catalytic materials. 相似文献
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采用软模板法制备了氮化钨-钨/掺氮有序介孔碳复合材料（WN-W/NOMC）,作为一种高比表面积且价格低廉的阴极氧还原反应催化剂。通过适量添加尿素来改变复合材料中的氮含量,在掺氮量为7%（w/w）时,实验发现材料能够保持完整有序介孔结构,测试其比表面积高达835 m2·g-1,透射电子显微镜（TEM）测试结果显示其催化颗粒均匀地分散在氮掺杂有序介孔碳载体上。在O2饱和的0.1 mol·L-1 KOH溶液中测试了材料的氧还原催化性能（ORR）,显示其起始电位为0.87 V（vs RHE）,极限电流密度为4.49 mA·cm-2,氧还原反应的转移电子数为3.4,接近于20%（w/w）商业Pt/C的3.8,说明该材料表现出近似4电子的氧还原反应途径。研究结果表明,WN-W/NOMC的催化性能虽然稍弱于商业铂碳（0.99 V,5.1 mA·cm-2）,但其具有远超铂碳的循环稳定性和耐甲醇毒化能力。 相似文献
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通过一种简易的模板法制备了有序介孔碳,即硅/P123三嵌段共聚物复合物经硫酸处理后,再加入蔗糖碳源经碳化和除硅处理合成出有序介孔碳。该方法与传统硬模板相比,其合成工序简单,成本更低;与其他简化合成方法相比,避免了由碳源不足而造成的介孔碳有序性低的缺点。通过小角XRD、N2吸脱附和HRTEM对样品及其中间过程进行了表征。结果表明,自晶化过程后,样品在合成的各个时期均保持着有序的介孔结构,当蔗糖添加量为1.5g时合成出的介孔碳材料有序性最高,比表面积和孔容也最高,分别为1261m2·g-1,1.03cm3·g-1。 相似文献
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有序中孔炭的制备及电性能研究 总被引：1，自引：1，他引：1
采用微湿含浸法制备了一系列具有不同比表面积和孔径分布的超级电容器有序中孔炭材料,同时采用Al-SBA-15为模板剂制得具有六方排列的空心炭管CMK-5.所制得的有序中孔炭的BET比表面积随糠醇加入量的增加而减小.电化学性能测试结果表明,在1mA·cm-2的充放电电流密度下各中孔炭材料比电容的大小顺序与其BET比表面积的大小顺序相一致.在所有样品中AlSC-0.8由于具有最大的比表面积,因此其比电容最大,达87.8F·g-1.倍率性能测试结果表明,具有CMK-3结构的SC-2.0的倍率性能最好,在50mA·cm-2的放电电流密度下其放电比电容接近AlSC-0.8有序中孔炭的水平. 相似文献
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Yifei Liao Yao Wang Ruixue Zhang Chaoling Wu Yigang Yan Prof. Yungui Chen 《ChemCatChem》2020,12(7):1958-1962
The widespread use of polymer electrolyte membrane fuel cells (PEMFCs) is still hindered by the sluggish activity and poor durability of cathode Pt-based catalysts. Ordered mesoporous carbons are used to inhibit the coarsening and detachment of Pt during oxygen reduction reaction (ORR). However, the long mesopores of OMCs make it hard to utilize the encapsulated Pt particles, leading to a poor ORR activity. Here, we have constructed an OMC with short mesoporous channel as support for confining Pt particles (Pt@s-OMC). Owing to the shortened meso-channels, the proton and oxygen transport is efficiently boosted, resulting an enhanced mass activity (167.1 mA mgPt−1 at 0.9 V); meanwhile, more metallic Pt and excellent pore structures guarantee the stability of Pt (88 % retention after 4000 cycles). Thus Pt@s-OMC possesses a superior activity and durability simultaneously. This work highlights a distinctive approach to settle the contradiction between high activity and durability, which provides a new insight into ORR catalysts. 相似文献
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以天然水菱镁矿为原料,通过\"煅烧-水化-煅烧\"的简单方法制备了高比表面积介孔网状MgO,且实验过程中无须加入任何试剂。系统性研究了氧化镁用量、吸附时间、吸附温度及pH对氧化镁吸附模拟废水中铅离子吸附性能的影响,揭示了吸附机理,并考察了氧化镁对多种离子的吸附效果。结果表明：该氧化镁吸附剂具有188 m2·g-1的高比表面积和0.85 cm3·g-1的高孔体积,平均孔径为12.33 nm,其吸附动力学和等温线数据与伪二级模型和Langmuir模型高度吻合,表明重金属离子在氧化镁上为单层化学吸附。MgO介孔网状结构表现出对Pb（Ⅱ）的高吸附性能,最大吸附量为7 431.5 mg·g-1,该数值远高于其他报道的基于MgO吸附剂的数值,铅去除率高达99.8%以上。介孔网状MgO的吸附机理主要是羟基官能团以及Mg（Ⅱ）与MgO表面重金属离子之间的离子交换所致。另外,该氧化镁可同时吸附多种离子,对Cd、Cr、Ni、As、Co、P、Se、Be、Bi、Cu、Fe、Mn、V、Zn、Al离子均具有优异的吸附性能。 相似文献
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To improve the initial coulombic efficiency and bulk density of ordered mesoporous carbons, active Fe2O3 nanoparticles were introduced into tubular mesopore channels of CMK-5 carbon, which possesses high specific surface area (>1700 m2·g?1) and large pore volume (>1.8 cm3·g?1). Fine Fe2O3 nanoparticles with sizes in the range of 5–7 nm were highly and homogenously encapsulated into CMK-5 matrix through ammonia-treatment and subsequent pyrolysis method. The Fe2O3 loading was carefully tailored and designed to warrant a high Fe2O3 content and adequate buffer space for improving the electrochemical performance. In particular, such Fe2O3 and mesoporous carbon composite with 47 wt% loading exhibits a considerably stable cycle performance (683 mAh·g?1 after 100 cycles, 99% capacity retention against that of the second cycle) as well as good rate capability. The fabrication strategy can effectively solve the drawback of single material, and achieve a high-performance lithium electrode material. 相似文献
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Dr. Matthias Steimecke Ana María Araújo-Cordero Emil Dieterich Prof. Dr. Michael Bron 《ChemElectroChem》2022,9(3):e202101221
In this work, the simultaneous investigation of a single cuprous oxide microcrystal towards CO2 electroreduction (CRR, CO2 reduction reaction) by using Raman microscopy and scanning electrochemical microscopy (SECM) is shown. Cu2O microcrystals were electrochemically crystallized on an indium-doped tin oxide-substrate (ITO). Structural changes of the Cu2O microcrystal are observed in situ by Raman microcopy, which indicates their fast conversion into elemental Cu at low overpotentials. Simultaneously, detection of products of the CO2 reduction is carried out electrochemically using the sample-generation tip-collection mode (SG/TC) of SECM and formate ions are the main product of CRR, as detected by a 10 μm Pt ultramicroelectrode (UME). Thus, with our approach, the very beginning of the CRR (onset potential), potential-dependent product formation as well as structural changes in the catalyst can be precisely investigated. 相似文献
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Chenwei Ma Dr. Yifeng Yun Dr. Tianfu Zhang Dr. Haiyun Suo Dr. Lai Yan Xianfeng Shen Prof. Yongwang Li Prof. Yong Yang 《ChemCatChem》2021,13(20):4350-4354
As a prerequisite elementary step, the reduction of cobalt (Co) oxides to form metallic Co is essential to display activity in heterogeneous catalysis. Nevertheless, the intrinsic principle of phase and morphology evolution for Co oxides and formation mechanism of the active Co site remains unclear. Here, we resolve this decades-long question by using a state-of-the-art in situ transmission electron microscopy (TEM) to elucidate the multi-role of initial crystalline phase and size of Co oxides in modulation of reduction rate, phase and morphology evolution under H2 atmosphere, by excluding the possible interference from promoter and support. We anticipate that this study enriches current understanding on the surface structure and morphology evolution of Co oxides, and provides reference for rational design of Co-based catalytic material as well as its pretreatment protocol. 相似文献
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