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Design and Synthesis of Novel Nanometallic Catalysts and Electrode Materials for Green Fuel Cells

机译：用于绿色燃料电池的新型纳米金属催化剂和电极材料的设计与合成

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摘要

The United Nations formally adopted 17 sustainable development goals (SDGs) at its 2015 summit. Many of these goals addressed issues such poverty, hunger, health, education, climate-change, gender equality, water, sanitation, energy, urbanization, environment and social justice. The seventh SDG seeks to ensure access to affordable, reliable, sustainable and modern energy for all. So among all renewable forms of energy, fuel cells with high efficiency have attracted a lot of attention recently. In particular, the direct ethanol fuel cells (DEFCs) and microbial fuel cells (MFCs) are significant due to their green fuel, less waste generated and environmental friendliness. Hence the overall goal of this work is to develop novel catalysts and electrodes for improving the efficiency of different designs of fuel cells.;Towards achieving this goal, the project was divided into three phases. For the first phase, a new electrode material was prepared for Ethanol Oxidation Reaction (EOR) based on Pt and alloyed PtCr nanoparticles fabricated via electrodeposition on a glassy carbon electrode. The catalyst was tested in acidic media. The typical SEM images showed the near spherical Pt structures with diameters in a range of 50--120 nm. The general size of the PtCr nanoparticles were determined to be around 105 nm and the surface aggregates were from 400 nm to 1microm at 40 cycles. However, the primary challenge has been attributed to the loss of the catalysts into solution. We hereby demonstrate an approach using poly(amic) acid (PAA) films as supporting material in order to improve the stability and inherently the efficiency of the catalysts. This catalyst was created via spin coating of PAA layer (thickness ~4microM) on the surface of electrocatalysts. The PAA/Pt and PAA/PtCr combination permits the diffusion of ethanol towards the surface of the Pt or PtCr nanoparticles resulting in efficient reduction while simultaneously preventing the loss of the catalysts into the solution. Electrode stability of 900 cycles (three days) was recorded at varying potential scan cycles. This electrode coated with PAA was found to be three times as durable when compared with the bare catalysts surface (300 cycles). And this work could allow the widespread use of these combinations for stable and efficient electrochemical reduction of ethanol.;The second phase was focused on the development of a new, easy, fast and green method to synthesize anisotropic Pt nanomaterials for application in EOR. The Pt nanomaterials were formed by combining sugar ligands with PtCl4 in water at room temperature and the reaction occurred immediately. Six types of sugar ligands were tested in this study: N,N'-dilactosylphenylene (LPDA), Lactose+p-aminosalicylic acid (LpAS), D-galactose+(3-amino) propylaniline (44DG), lactose-4,4-ethylenedianiline (L-44EDA), galactose-4,4-ethylenedianiline (G-44EDA) and galactose-4-sulfonyl phenyelendianiline (GPSA). Based on the intrinsic chemical structures and properties of the different sugar ligands, various sizes and shapes of Pt nanomaterials were generated, including uniform tiny nanoparticles and fancy nanoflowers. The electrochemical properties of the sugar ligands were determined using cyclic voltammetry (CV) which showed that LPDA exhibited the greatest electroactive property with two redox couples at 0.28 V and 0.68 V, respectively. And based on the Randles Sevcik equation calculation, the results demonstrated that the redox reaction of LPDA is reversible with two numbers of electrons transferred.;The third and final phase of the project was the development of two different designs of microbial fuel cells. The first design was the traditional one-chamber MFC. So, in order to prove the performance of fuel cell, Pt nanoparticles were electrodeposited onto reticulated vitreous carbon electrode (RVC). Subsequent experiments confirmed that the power density of MFC increased by two times when compared with that containing no Pt catalyst. The second design was a microfluidic-based MFCs using paper as the substrates, which was carried out in collaboration with Choi's research group at BU. Our objective was to develop novel paper-based electrodes for improving the performance of paper MFCs. PAA was employed for the first time as a supporting material for Origami or paper-based design of MFCs due to its hydrophilicity and electrical conductivity.;Overall, this work has shown that different methods had been successfully used to synthesis metallic catalysts and electrodes materials for different types of green fuel cells. Because ethanol is a great alternative green fuel, the electrodeposited Pt and PtCr alloy showed superior performance for EOR, especially after modifying with PAA, the overall efficiency of the DEFCs were increased by three times. Finally, since water has been used as fuel and bacteria as catalysts, the new electrodes materials reported in this work helped to improve the power output and current density of the MFCs compared with previous work. Hence this project could potentially contribute to achieving the seventh SDG of affordable, reliable, sustainable and modern energy for all. (Abstract shortened by ProQuest.).
机译：联合国在其2015年首脑会议上正式通过了17个可持续发展目标。其中许多目标涉及贫困，饥饿，健康，教育，气候变化，性别平等，水，卫生，能源，城市化，环境和社会正义等问题。第七个可持续发展目标旨在确保所有人都能获得负担得起的，可靠的，可持续的和现代的能源。因此，在所有可再生能源中，高效燃料电池近来引起了很多关注。特别地，直接乙醇燃料电池（DEFCs）和微生物燃料电池（MFCs）由于其绿色燃料，较少的废物产生和环境友好性而非常重要。因此，这项工作的总体目标是开发新型催化剂和电极，以提高燃料电池不同设计的效率。为实现这一目标，该项目分为三个阶段。对于第一阶段，基于在玻璃碳电极上电沉积制备的Pt和合金化的PtCr纳米粒子，为乙醇氧化反应（EOR）制备了新的电极材料。催化剂在酸性介质中测试。典型的SEM图像显示了直径在50--120 nm范围内的近球形Pt结构。 PtCr纳米粒子的一般尺寸确定为约105 nm，表面聚集体在40个循环中为400 nm至1微米。然而，主要挑战归因于催化剂向溶液中的损失。我们由此证明使用聚（酰胺）酸（PAA）膜作为载体材料的一种方法，以提高催化剂的稳定性和固有的效率。该催化剂是通过在电催化剂表面上旋涂PAA层（厚度约4 microM）而产生的。 PAA / Pt和PAA / PtCr组合允许乙醇向Pt或PtCr纳米颗粒的表面扩散，导致有效还原，同时防止催化剂损失到溶液中。在不同的电势扫描周期下记录了900个周期（三天）的电极稳定性。已发现，与裸露的催化剂表面相比（300次循环），这种涂有PAA的电极的耐久性是其三倍。这项工作可以使这些组合物广泛用于稳定，有效地电化学还原乙醇。在室温下，通过将糖配体与PtCl4结合形成Pt纳米材料，并立即发生反应。在这项研究中测试了六种类型的糖配体：N，N'-二乳糖基亚苯基（LPDA），乳糖+对氨基水杨酸（LpAS），D-半乳糖+（3-氨基）丙基苯胺（44DG），乳糖4,4-亚乙基二苯胺（L-44EDA），半乳糖-4,4-亚乙基二苯胺（G-44EDA）和半乳糖4-磺酰基苯乙二胺（GPSA）。根据不同糖配体的内在化学结构和性质，生成了各种尺寸和形状的Pt纳米材料，包括均匀的微小纳米颗粒和花式纳米花。使用循环伏安法（CV）测定糖配体的电化学性质，结果表明，LPDA表现出最大的电活性，两个氧化还原对分别为0.28 V和0.68V。并基于Randles Sevcik方程计算，结果表明，在两个电子转移的情况下，LPDA的氧化还原反应是可逆的。该项目的第三个也是最后一个阶段是开发两种不同设计的微生物燃料电池。第一个设计是传统的单室MFC。因此，为了证明燃料电池的性能，将Pt纳米颗粒电沉积在网状玻璃碳电极（RVC）上。随后的实验证实，与不含Pt催化剂的MFC相比，MFC的功率密度提高了两倍。第二种设计是与纸的Choi研究小组合作进行的，以纸为基材的基于微流体的MFC。我们的目标是开发新颖的纸基电极，以改善纸MFC的性能。由于其亲水性和导电性，PAA首次被用作MFC折纸或纸基设计的支撑材料。总体而言，这项工作表明，已经成功地使用了各种方法来合成金属催化剂和电极材料。不同类型的绿色燃料电池。由于乙醇是一种很好的替代绿色燃料，因此电沉积的Pt和PtCr合金表现出优异的EOR性能，尤其是在用PAA改性后，DEFC的整体效率提高了三倍。最后，由于水已被用作燃料，细菌被用作催化剂，与以前的工作相比，这项工作中报道的新电极材料有助于改善MFC的功率输出和电流密度。因此，该项目可能有助于实现第七项可持续发展目标，即所有人都能负担得起，可靠，可持续和现代的能源。 （摘要由ProQuest缩短。）。

著录项

  • 作者

    Zhang, Jing.;

  • 作者单位

    State University of New York at Binghamton.;

  • 授予单位 State University of New York at Binghamton.;
  • 学科 Materials science.;Mechanical engineering.
  • 学位 Ph.D.
  • 年度 2018
  • 页码 253 p.
  • 总页数 253
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 水产、渔业;
  • 关键词

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