共查询到18条相似文献，搜索用时 46 毫秒
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以甲酸钠为还原剂,在水/triton X-100/乙二醇/环己烷的W/O型微乳液中制备PtSn/C催化剂.采用X射线衍射（XRD）分析催化剂的结构,循环伏安法和电化学阻抗谱法测试催化剂对乙醇的催化氧化性能.结果表明,微乳法制备的PtSn/C催化剂部分合金化,与Pt/C相比,PtSn/C对乙醇的电催化氧化活性有明显提高,具有更高的抗CO中毒能力. 相似文献
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采用化学还原浸渍法在两种不同条件下制备炭载PtRu催化剂,通过XRD和TEM技术对催化剂的晶体结构及微观形貌进行了分析,运用循环伏安法、线性扫描法来检测不同条件下制备的催化剂对甲醇及吸附态CO(COad)电催化氧化活性的影响.结果表明,不同条件下制备的催化剂Pt和Ru形成合金的程度不同,Pt-Ru合金原子的颗粒在载体炭上的粒径大小和分布不同,导致催化剂对甲醇及COad的电氧化催化活性不同.其中以甲醛为还原剂在乙二醇体系中制备的催化剂PtRu/C-2能形成较好的合金状态,粒径小,分布均匀,对甲醇及COad的氧化具有较高的电催化活性. 相似文献
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采用改进的B?nnemann法成功制备了Pt/C、Pt-Ni_(1/3)/C、Pt-SnO_2/C、Pt-Ni_x-SnO_2/C(x=1/4,1/3,2/3,1)阳极电催化剂。利用X射线衍射(XRD)、高分辨透射电子显微镜(HR-TEM)以及X射线光电子能谱(XPS)对催化剂晶型结构、表面形貌和表面电子结构进行了表征。运用线性扫描伏安(LSV)和电流密度-时间(j-t)曲线进行电化学测试,研究了乙醇电催化氧化(EOR)活性。并用原位红外光谱(in situ FT-IR)研究了EOR过程中产物的分布。结果表明,Pt-Ni_(1/3)-SnO_2/C是由Pt-Ni合金和SnO_2两相组成。XPS结果表明,在Pt-SnO_2中添加微量的Ni,Pt表面电子结构发生了改变。电化学结果表明,三元催化剂的EOR活性均优于二元和纯Pt,其中Pt-Ni_(1/3)-SnO_2/C的EOR活性最佳。Ni和SnO_2的加入并没有显著提高乙醇C―C键的断裂能力,但是二者的协同作用在低电位(0.1 V)下加强了乙醛的进一步氧化,生成了乙酸。 相似文献
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制备方法对PtMo/C催化剂上CO电催化氧化性能的影响 总被引：3，自引：0，他引：3
用化学还原法、胶体法和Adams法制备了PtMo/C电催化剂, 对其物理化学性质及其在CO电氧化反应中的催化性能进行了对比研究. TEM和XRD测试结果表明, 胶体法制备的催化剂颗粒在载体炭上均匀分布, 颗粒粒径约5 nm;由化学还原法制备的颗粒尺寸较大, 而Adams法制备的颗粒尺寸达数十纳米, 并有严重的团聚现象. CO消除伏安法测试结果表明, 三种制备方法中胶体法制备的PtMo/C催化剂具有最高的电化学表面积和电催化活性. 与常用的Pt/C催化剂相比, PtMo/C催化剂中Pt上弱吸附态CO的电氧化均得到了促进, 而强吸附态CO则不受影响. 这些结果表明PtMo颗粒的尺寸分布和在载体上的分散状况是影响PtMo/C催化剂电催化性能的主要因素. 胶体法制备的PtMo/C与常用的PtRu/C相比, 电化学表面积虽然较低, 但在低电势下CO的起始氧化电势只有0.15 V, 而且在0.15～0.5０ V之间发生电氧化的CO达到其总量的1/3. 相似文献
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乙醇在Pt/nanoTiO2-CNT复合催化剂上的电催化氧化 总被引：10，自引：0，他引：10
通过前驱体Ti(OEt)4直接水解和电化学扫描电沉积法制备在Ti基体上的纳米TiO2-碳纳米管复合膜载Pt(Pt/nanoTiO2-CNT)复合催化剂. 透射电镜 (TEM) 和X射线衍射 (XRD) 结果表明, 锐钛矿型纳米TiO2粒子和Pt纳米粒子(粒径均为5~10 nm)均匀地分散在碳纳米管表面. 通过循环伏安和计时电流法研究表明, Pt/nanoTiO2-CNT 复合催化剂(Pt载量为0.32 mg•cm−2) 具有高达51.8 m2•g−1的电化学活性比表面积, 常温常压下对乙醇的电化学氧化具有高催化活性和稳定性, 乙醇氧化峰电位分别为0.59、0.96和0.24 V, 氧化峰电流密度分别达到−115、−113和−75 mA•cm−2. 复合催化剂对乙醇电氧化的高催化活性可归因于nanoTiO2、CNT和Pt纳米粒子的协同催化作用. 相似文献
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Amaury F. B. Barbosa Vinicius Del Colle Ana M. Gómez-Marín Camilo A. Angelucci Dr. Germano Tremiliosi-Filho 《Chemphyschem》2019,20(22):3045-3055
In the present work, the Pt(111) surface was disordered by controlling the density of {110}- and {100}-type defects. The cyclic voltammogram (CV) of a disordered surface in acid media consists of three contributions within the hydrogen adsorption/desorption region: one from the well-ordered Pt(111) symmetry and the other two transformed from the {111}-symmetry with contributions of {110}- and {100}-type surface defects. The ethanol oxidation reaction (EOR) was studied on these disordered surfaces. Electrochemical studies were performed in 0.1 M HClO4+0.1 M ethanol using cyclic voltammetry and chronoamperometry. Changes in current densities associated to the specific potentials at which each oxidation peak appears suggest that different surface domains of disordered platinum oxidize ethanol independently. Additionally, as the surface-defect density increases, the EOR is catalysed better. This tendency is directly observed from the CV parameters because the onset and peak potentials are shifted to less positive values and accompanied by increases in the oxidation-peak current on disordered surfaces. Similarly, the CO oxidation striping confirmed this same tendency. Chronoamperometric experiments showed two opposite behaviors at short oxidation times (0.1 s). The EOR was quickly catalyzed on the most disordered surface, Pt(111)-16, and was then rapidly deactivated. These results provide fundamental information on the EOR, which contributes to the atomic-level understanding of real catalysts. 相似文献
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Dr. José J. Arroyo-Gómez Dr. Deicy Barrera Rodrigo M. Castagna Dr. Juan Manuel Sieben Dr. Andrea E. Alvarez Prof. Marta M. E Duarte Prof. Karim Sapag 《ChemCatChem》2019,11(15):3451-3464
In this work, we prepared four electrocatalysts based on trimetallic PtPdNi nanoparticles on different carbon supports, i. e., i) two activated carbons produced from biomass, ii) micro-mesoporous carbon synthesized by the nanocasting method, and iii) commercial carbon black. The electrocatalytic activity of the prepared materials was tested in the electro-oxidation of ethanol in alkaline medium. Well-distributed nanoparticles with sizes in the range of 3.5–5.2 nm were obtained through galvanic replacement. The bulk Pt, Pd and Ni contents were about 65, 25 and 15 at. %, measured by EDX and ICP-AES. By XPS the surface Pt : Pd atomic ratios were in the range of 1.82–2.2. Electrochemical experiments showed that the trimetallic nanoparticles deposited over micro-mesoporous carbon material exhibit the highest electrochemical activity towards ethanol electro-oxidation in alkaline medium. Results showed that both synthetic carbon and biomass-derived carbon are suitable materials to support electrocatalysts in low-temperature fuel cells. 相似文献
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Sn（Ⅱ）／Sn（Ⅳ）对PtSn／C乙醇电化学氧化活性的影响 总被引：3，自引：0，他引：3
在乙二醇共还原H2PtCl6和SnCl2的过程中加入Ni(NO3)2作为助剂制备了PtSn/C-Ni催化剂. 程序升温还原实验检测到该催化剂中存在Sn(Ⅱ)/Sn(Ⅳ)氧化还原电对. 线性扫描、单电池性能测试和CO溶出实验表明,提高催化剂中Sn(Ⅱ)/Sn(Ⅳ)的比值能显著提高催化剂的乙醇电化学氧化活性和抗CO中毒能力. 催化剂电催化活性提高的原因可能是Sn(Ⅱ)/Sn(Ⅳ)电对加快了(OH)ads 物种在催化剂中的传递速率,促进了乙醇电化学氧化过程中产生的类CO中间物种在Pt表面的氧化. 相似文献
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A comparative study of the electro-oxidation of ethanol and 2-propanol was carried out on carbon-supported platinum particles.
Cyclic voltammetry, steady state polarisation, and electrochemical impedance spectroscopy were used to investigate the oxidation
reactions. A difference in the mechanistic behaviour of the oxidation of ethanol and 2-propanol on Pt was observed, thereby
highlighting the fact that the molecular structure of the alcohol has great influence on its electroreactivity. The study
emphasizes the fact that 2-propanol is a promising fuel candidate for a direct alcohol fuel cell. 相似文献
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In addition to the theoretical research, direct ethanol fuel cells have great potential in practical applications. The performance of direct ethanol fuel cells largely depends on the electrocatalysts. Pt-based electrocatalysts have been promising candidates for advancing direct ethanol fuel cells for its high catalytic activity and great durability. Here, a PtSn catalyst with unique three-dimensional porous nanostructure has been designed and synthesized via a two-step liquid phase reduction reaction. Sn formed a self-supporting framework in PtSn alloy particles (∼3.5 nm). In ethanol electro-oxidation reaction, the PtSn catalyst exhibited high mass activity and excellent recycling time compared with that of Pt/C. After the morphology characterization before and after potential cycling, the PtSn alloy-based nano-catalyst showed good stability. The PtSn catalysts effectively avoid structural instability due to the external carriers, and prolong the leaching time of Sn. In addition, the introduction of a certain amount of Sn can also solve the poisoning phenomenon of active sites on Pt surface. The design strategy of porous alloy nano-catalyst sheds light on its applications in direct ethanol fuel cells. 相似文献