J.Q. 和文学硕士承认 Villum 基金会的支持, 以块津贴的形式。急诊和硕士从丰田中心研发 & 研发实验室获得支持, J.Q. 已经从欧洲联盟2020《玛丽居里夫人-居里赠款协议》703366的研究和创新项目中得到了资金。

1. 合成 50 wt% 铂/丙催化剂
<ol><li>
铂纳米粒子的胶体合成 (NPs)
	<ol>
<li>为了获得2毫微米 Pt 核动力源的胶体悬浮, 在微波反应容器中, 用4毫升的氢氧化钠溶液在0.4 米的乙二醇 (例如) 与4毫升 H2PtCl6· 6H2O 在40毫米。</li>
		<li>用微波反应器在160摄氏度加热混合物3分钟 (动态模式, 加热功率: 100 W, 搅拌: 低)。</li>
	</ol>
</li>
	<li>
在碳支架上固定 Pt 核动力源
	<ol>
<li>添加30毫升的1米 HCl 溶液, 7.3 毫升的胶体 Pt NPs 悬浮沉淀。将混合物离心在相对离心力为 2900 x g (5000 转每分钟 (rpm)) 5 分钟, 并丢弃上清溶剂。重复这些洗涤/离心步骤两次。 注: 所有化学品应根据当地机构的规则收集和处置。</li>
		<li>在7毫升丙酮中重新分散 Pt 核动力源。在1毫升丙酮中分散27.5 毫克的炭黑。混合丙酮分散和蒸发丙酮在旋转蒸发器 (40 °c, 200 毫巴) 或 Schlenk 线 (40 °c, 200 毫巴), 直到完全干燥。</li>
		<li>将获得的铂/丙催化剂粉末在烤箱 (120 °c) 过夜。</li>
		<li>添加去离子 (DI) 水到 Pt/C 催化剂粉末和油脂实验 (35 赫, 160 瓦特) 它在一个超声波浴充满冷水 (< 5 °c) 为3分钟. 过滤器和洗涤催化剂用 DI 水在滤纸 (4-7 µm)。在真空烤箱中干燥催化剂粉末 (100-120 °c, 10 帕)。 注: 此过程导致55毫克的 pt/C 催化剂与 pt wt% 50 和 pt 颗粒大小的ca. 2 nm。为了准备更多的 Pt/C 催化剂, 将各自的数量放大到1:1 的比例。通过将 pt 核动力源的量变化为炭黑, 可在10至 70-80 wt% 之间调整 pt 负载, 而不产生明显的 NP 团聚。</li>
		<li>要制造催化剂墨水, 可将6.3 毫克的 50 wt% 铂/丙催化剂粉末与6毫升的 DI 水和2毫升异丙醇 (IPA) 混合在一起。添加少量1米的 KOH 溶液 (~ 10 µL), 以调整油墨的 pH 值约为10。将含有混合物的玻璃瓶放在一个充满冷水 (< 5 °c) 和油脂实验 (35 赫, 160 瓦特) 的超声波浴中, 用于15分钟。 注意: 不要先向催化剂中添加 IPA。如果将酒精添加到干铂/丙催化剂粉末中, 催化剂就会着火。</li>
	</ol>
</li>
</ol>2. pt 核动力源和 pt/C 催化剂的表征
<ol><li>
Pt 核动力源的透射电镜 (TEM) 表征
	<ol>
<li>添加30毫升的1米 HCl 溶液, 7.3 毫升的胶体 Pt NPs 悬浮沉淀。将混合物离心在相对离心力为 2900 x g (5000 转每分钟 (rpm)) 5 分钟, 并丢弃上清溶剂。重复这些洗涤/离心步骤两次。</li>
		<li>在 Pt NP 悬浮液中取一滴 (ca 100 µL), 再将其分散在1毫升丙酮中。</li>
		<li>把稀释的, 重新分散的核动力源放在一张滤纸上 (用正常的碳膜), 吸收多余的溶剂, 让网格在空气中干燥。</li>
		<li>使用至少3种不同的放大 (例如、100,000X、300,000X、400,000X), 通过对网格至少5个不同区域进行成像来分析粒子大小分布。从显微照片中测量至少300个 NPs 的大小 (和相关大小分布)。</li>
	</ol>
</li>
	<li>
铂/丙催化剂的 TEM 表征
	<ol>
<li>稀释催化剂墨水 (上面描述) 两次与 100% IPA。将稀释后的催化剂墨水放在 TEM 网格上 (用孔或莱西碳膜) 放置在滤纸上, 以吸收多余的溶剂, 让网格在空气中干燥。</li>
		<li>使用至少3种不同的放大 (例如、100,000X、300,000X、400,000X), 通过对网格至少5个不同区域进行成像来分析粒子大小分布。从显微照片中测量至少300个 NPs 的大小 (和相关大小分布)。 注: 通过观察 Pt/C 催化剂粒子, 并与网格的碳膜不重叠, 获得了较好对比度的 TEM 图像。这是使用 TEM 网格与孔或莱西碳膜在这里的优势。</li>
	</ol>
</li>
	<li>
用王水消化 Pt NPs 
	<ol>
<li>在真空烤箱 (80 摄氏度, 10 帕) 一夜之间干燥 Pt/C 催化剂。在陶瓷坩埚中称量催化剂粉末。</li>
		<li>在消音器熔炉 (空气, 900 °c, 30 分钟) 的坩埚中加热催化剂粉末, 以烧毁碳支持。在坩埚上盖上盖子, 防止催化剂粉末在加热过程中飞行。</li>
		<li>添加4毫升的王水 (混合 30% HCl 和 65% HNO 3在体积比 3:1) 到坩埚和加热的混合物在一个热板在ca. 80 °c 为 2 h。 注意: 王水是一种积极的酸性, 应该小心处理. </li>
		<li>将最终体积调整到10毫升的 DI 水。</li>
		<li>用电感耦合等离子体质谱 (ICP) 15或紫外可见光谱 (如下所述) 确定王水溶液中 Pt 的浓度。</li>
	</ol>
</li>
	<li>
通过紫外-可见光法测定铂负荷
	<ol>
<li>混合0.75 毫升2米 hcl 与0.25 毫升1米 SnCl2在 4 M hcl 中制备的石英试管和添加1毫升的王水样品。</li>
		<li>在 2 M hcl 中, 测量1.75 毫升2米 hcl 和0.25 毫升1米 SnCl4的混合物的紫外可见光谱作为基线。</li>
		<li>测量样品混合物的紫外可见光谱 (700 毫微米-350 nm)。</li>
		<li>将 Pt 标准溶液的5µL (1000 ppm) 添加到样品溶液中, 搅拌好, 测量紫外可见光谱。重复添加 Pt 标准溶液和测量4次。</li>
		<li>减去吸收量在 680 nm (基线) 从吸光度在 402 nm (峰值), 并绘制它反对的浓度添加 Pt. 从校准曲线的 x 截距确定王水样本中 Pt 的浓度. </li>
	</ol>
</li>
</ol>3. 旋转圆盘电极 (RDE) 测量 Pt/C 催化剂
<ol><li>
光散射测量催化剂墨水的表征
	<ol>
<li>用 ph 计测量催化剂墨水的 ph 值。</li>
		<li>通过加入 IPA/H2O (1:3, v: v) 混合溶剂稀释催化剂墨水50倍。添加酸或碱, 以保持催化剂油墨的 pH 值恒定。</li>
		<li>使用光散射装置的电泳光散射 (16模式) 测量50X 稀释试样的泽塔电位。</li>
		<li>使用光散射装置的动态光散射 (dl)17测量稀释样品中的聚合体的大小。</li>
	</ol>
</li>
	<li>
催化剂薄膜制造
	<ol>
<li>用氧化铝糊 (前0.3 µm, 0.05 µm) 将玻碳 (GC) 圆盘电极 (直径5毫米) 镜面抛光, 并在 DI 水中进行超声波清洗。</li>
		<li>将催化剂墨水的5µL 整除到 GC 电极上, 导致 pt 负载为10µgPt cm-2。在 Ar 气体流动下干燥油墨, 使其在涌泉中以混合的 IPA 和 DI 水 (17:3, v: v) 的混合物湿润。 注意: 通过改变涌泉中的 IPA 和 DI 水的比例, 可以优化干燥条件。</li>
		<li>确认 GC 电极表面由 CCD 摄像机均匀覆盖在催化剂薄膜上。</li>
	</ol>
</li>
	<li>
电化学测量
	<ol>
<li>使用电化学玻璃或聚四氟乙烯 (PTFE) 细胞的基础上, 三室配置的所有电化学测量。分别使用改进的 GC 磁盘电极、铂网和被困氢/饱和甘汞电极 (SCE) 作为工作电极、反电极和参考电极。 注: 当使用 SCE 用于避免氯离子的扩散时, 需要用氟膜 (例如nafion 膜) 将所述电极的单元的子隔间与主隔间隔开。</li>
		<li>将单元格和组件浸泡在混合酸中 (H2, 因此4: HNO3 = 1:1, v: v) 过夜。随后, 用 di 水彻底冲洗细胞和其他成分, 并在二次水中煮沸。 注: 每月至少用混合酸清洁细胞 (视使用频率而定)。 注意: 小心处理混合酸。在电化学实验之间, 煮沸并保持被盖子覆盖的 DI 水中的细胞。</li>
		<li>将 0.1 M HClO4电解质溶液倒入电化学电池中。将3电极 (工作电极、计数器电极和参考电极) 放置在单元格的每个隔间, 并将电极连接到恒电位仪。</li>
		<li>测量工作电极与 Luggin 毛细管 (iR-30 Ω) 之间电解质的电阻, 并利用恒电位仪的模拟正反馈方案对整个测量过程进行补偿。产生的有效溶液阻力小于3Ω。 注: 如果恒电位仪没有模拟反馈方案, 请应用基于软件的 iR 降补偿。</li>
		<li>校准参考电极。用 H2气体清除电解质, 并扫描 50 mV 的-1的扫描速率。确定当前密度等于0毫安 cm-2作为 0 V 与可逆氢电极的电位。</li>
		<li>用 Ar 气体 (ca 0.3 L 最小-1) 清除电解质。在扫描速率为 0.05 v s-1的情况下, 用0.05 和 1.20 v 之间的潜在循环清洁催化剂, 直到观察到稳定的循环伏安 (~ 50 循环)。</li>
		<li>
执行背景测量。
		<ol>
<li>记录一个循环伏安 (CV) 作为背景测量。用 Ar 气体 (ca 0.3 L 最小-1) 清除电解质。扫描速度为 0.05 v s-1时, 将0.05 和 1.10 v 之间的电位扫出。</li>
		</ol>
</li>
		<li>
执行 ORR 活动测量。
		<ol>
<li>在 O2清除的电解质中记录循环伏安 (ca 0.3 L 最小-1)。扫描速度为 0.05 v s-1和旋转速度为 1600 rpm 的0.05 和 1.10 V 之间的电位。</li>
		</ol>
</li>
		<li>
执行 CO 溶出伏安法。
		<ol>
<li>将工作电极在 CO 清除 (ca 0.3 L 最小-1) 中, 通过电解质进行5分钟, 后跟 Ar 清除 (ca 0.3 L 最小-1), 用于10分钟。随后, 扫描速度为 0.05 v s-1, 将电位从 0.05 v 到 1.10 v 扫出。 注意: 检查是否允许使用 CO 气体;如果是这样, 这项工作必须在通风罩中进行, 并且需要采取安全措施。</li>
		</ol>
</li>
		<li>电化学测量后, 将催化剂膜在气相色谱电极上, 通过压在纸张上的电极上, 将其转移到纸巾上, 并对所述转移的催化剂膜进行照相。</li>
	</ol>
</li>
	<li>
数据分析
	<ol>
<li>计算 co 氧化峰电荷 QCO中催化剂的电化学表面面积 (欧洲), 同时考虑到扫描速度, Pt 负载 L, 并使用390µC cm <img alt="Equation 1" src="/files/ftp_upload/57105/57105eq1.jpg"> </img>-2Pt的转换系数。(二电子过程)6。 注意: 或者, 欧洲可以用195µC cm-2Pt (一个电子过程) 的转换系数在 Ar 清除的电解质中记录伏安的 Hupd (QH) 区域来计算。 <img alt="Equation 2" src="/files/ftp_upload/57105/57105eq2.jpg"> <img alt="Equation 3" src="/files/ftp_upload/57105/57105eq3.jpg">
</li>
		<li>通过从 O2清除的电解质中记录的伏安中减去在 Ar 清除的电解质中记录的循环伏安, 纠正 nonfaradaic 背景。使用修正后的伏安和 Koutecky-列维奇方程的阳极扫描, 确定 ORR 动态电流密度, jk: <img alt="Equation 4" src="/files/ftp_upload/57105/57105eq4.jpg"> 注意: 这里的j和jd 分别代表了测量电流密度和扩散极限电流密度。</li>
	</ol>
</li>
</ol>

<ol>
	<li>Stephens, I. E. L., Rossmeisl, J., Chorkendorff, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+sustainable+fuel+cells.">Toward sustainable fuel cells.</a> Science. 354 (6318), 1378-1379 (2016).</li><li>Chen, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+Crystalline+Multimetallic+Nanoframes+with+Three-Dimensional+Electrocatalytic+Surfaces.">Highly Crystalline Multimetallic Nanoframes with Three-Dimensional Electrocatalytic Surfaces.</a> Science. 343 (6177), 1339-1343 (2014).</li><li>Schmidt, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+high-surface+area+electrocatalysts+using+a+rotating+disk+electrode+configuration.">Characterization of high-surface area electrocatalysts using a rotating disk electrode configuration.</a> J. Electrochem. Soc. 145 (7), 2354-2358 (1998).</li><li>Gasteiger, H. A., Kocha, S. S., Sompalli, B., Wagner, F. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activity+benchmarks+and+requirements+for+Pt,+Pt-alloy,+and+non-Pt+oxygen+reduction+catalysts+for+PEMFCs.">Activity benchmarks and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs.</a> Appl. Catal. B-Environm. 56 (1-2), 9-35 (2005).</li><li>Kocha, S. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Best+Practices+and+Testing+Protocols+for+Benchmarking+ORR+Activities+of+Fuel+Cell+Electrocatalysts+Using+Rotating+Disk+Electrode.">Best Practices and Testing Protocols for Benchmarking ORR Activities of Fuel Cell Electrocatalysts Using Rotating Disk Electrode.</a> Electrocatalysis. 8 (4), 366-374 (2017).</li><li>Mayrhofer, K. J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+oxygen+reduction+activities+via+the+rotating+disc+electrode+method:+From+Pt+model+surfaces+to+carbon-supported+high+surface+area+catalysts.">Measurement of oxygen reduction activities via the rotating disc electrode method: From Pt model surfaces to carbon-supported high surface area catalysts.</a> Electrochim. Acta. 53 (7), 3181-3188 (2008).</li><li>Mayrhofer, K. J. J., Ashton, S. J., Kreuzer, J., Arenz, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Electrochemical+Cell+Configuration+Incorporating+an+Ion+Conducting+Membrane+Separator+between+Reference+and+Working+Electrode.">An Electrochemical Cell Configuration Incorporating an Ion Conducting Membrane Separator between Reference and Working Electrode.</a> Intern. J. Electrochem. Sci. 4 (1), 1-8 (2009).</li><li>Nesselberger, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Particle+Size+Effect+on+the+Oxygen+Reduction+Reaction+Activity+of+Pt+Catalysts:+Influence+of+Electrolyte+and+Relation+to+Single+Crystal+Models.">The Particle Size Effect on the Oxygen Reduction Reaction Activity of Pt Catalysts: Influence of Electrolyte and Relation to Single Crystal Models.</a> J. Am. Chem. Soc. 133 (43), 17428-17433 (2011).</li><li>Ke, K., Hiroshima, K., Kamitaka, Y., Hatanaka, T., Morimoto, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+accurate+evaluation+for+the+activity+of+nano-sized+electrocatalysts+by+a+thin-film+rotating+disk+electrode:+Oxygen+reduction+on+Pt/C.">An accurate evaluation for the activity of nano-sized electrocatalysts by a thin-film rotating disk electrode: Oxygen reduction on Pt/C.</a> Electrochim. Acta. 72, 120-128 (2012).</li><li>Shinozaki, K., Zack, J. W., Richards, R. M., Pivovar, B. S., Kocha, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxygen+Reduction+Reaction+Measurements+on+Platinum+Electrocatalysts+Utilizing+Rotating+Disk+Electrode+Technique.">Oxygen Reduction Reaction Measurements on Platinum Electrocatalysts Utilizing Rotating Disk Electrode Technique.</a> J. Electrochem. Soc. 162 (10), F1144-F1158 (2015).</li><li>Zalitis, C. M., Sharman, J., Wright, E., Kucernak, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+the+hydrogen+oxidation+reaction+on+Pt/C+catalysts+at+optimised+high+mass+transport+conditions+and+its+relevance+to+the+anode+reaction+in+PEFCs+and+cathode+reactions+in+electrolysers.">Properties of the hydrogen oxidation reaction on Pt/C catalysts at optimised high mass transport conditions and its relevance to the anode reaction in PEFCs and cathode reactions in electrolysers.</a> Electrochim. Acta. 176, 763-776 (2015).</li><li>Wiberg, G. K. H., Fleige, M. J., Arenz, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+test+of+a+flexible+electrochemical+setup+for+measurements+in+aqueous+electrolyte+solutions+at+elevated+temperature+and+pressure.">Design and test of a flexible electrochemical setup for measurements in aqueous electrolyte solutions at elevated temperature and pressure.</a> Rev. Sci. Instr. 85 (8), 085105 (2014).</li><li>Wiberg, G. K. H., Fleige, M., Arenz, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gas+diffusion+electrode+setup+for+catalyst+testing+in+concentrated+phosphoric+acid+at+elevated+temperatures.">Gas diffusion electrode setup for catalyst testing in concentrated phosphoric acid at elevated temperatures.</a> R Rev. Sci. Instr. 86 (2), 024102 (2015).</li><li>Inaba, M., Quinson, J., Arenz, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=pH+matters:+The+influence+of+the+catalyst+ink+on+the+oxygen+reduction+activity+determined+in+thin+film+rotating+disk+electrode+measurements.">pH matters: The influence of the catalyst ink on the oxygen reduction activity determined in thin film rotating disk electrode measurements.</a> J. Power Sources. 353, 19-27 (2017).</li><li>Cherevko, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissolution+of+Platinum+in+the+Operational+Range+of+Fuel+Cells.">Dissolution of Platinum in the Operational Range of Fuel Cells.</a> ChemElectroChem. 2 (10), 1471-1478 (2015).</li><li>Ware, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophoretic+light+scattering.">Electrophoretic light scattering.</a> Adv. Colloid Interface Sci. 4 (1), 1-44 (1974).</li><li>Berne, B. J., Pecora, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Dynamic Light Scattering, with applications to Chemistry, Biology and Physics. , (2000).</li><li>Baranova, E. A., Bock, C., Ilin, D., Wang, D., MacDougall, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infrared+spectroscopy+on+size-controlled+synthesized+Pt-based+nano-catalysts.">Infrared spectroscopy on size-controlled synthesized Pt-based nano-catalysts.</a> Surf. Sci. 600 (17), 3502-3511 (2006).</li><li>Garsany, Y., Singer, I. L., Swider-Lyons, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+film+drying+procedures+on+RDE+characterization+of+Pt/VC+electrocatalysts.">Impact of film drying procedures on RDE characterization of Pt/VC electrocatalysts.</a> J. of Electroanal. Chem. 662 (2), 396-406 (2011).</li><li>Garsany, Y., Baturina, O. A., Swider-Lyons, K. E., Kocha, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+Methods+for+Quantifying+the+Activity+of+Platinum+Electrocatalysts+for+the+Oxygen+Reduction+Reaction.">Experimental Methods for Quantifying the Activity of Platinum Electrocatalysts for the Oxygen Reduction Reaction.</a> Anal. Chem. 82 (15), (2010).</li><li>Kongkanand, A., Mathias, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Priority+and+Challenge+of+High-Power+Performance+of+Low-Platinum+Proton-Exchange+Membrane+Fuel+Cells.">The Priority and Challenge of High-Power Performance of Low-Platinum Proton-Exchange Membrane Fuel Cells.</a> J. Phys. Chem. Lett. 7 (7), 1127-1137 (2016).</li><li>Speder, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pt+based+PEMFC+catalysts+prepared+from+colloidal+particle+suspensions+-+a+toolbox+for+model+studies.">Pt based PEMFC catalysts prepared from colloidal particle suspensions - a toolbox for model studies.</a> Phys. Chem. Chem. Phys. 15 (10), 3602-3608 (2013).</li><li>Neumann, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoparticles+in+a+box:+a+concept+to+isolate,+store+and+re-use+colloidal+surfactant-free+precious+metal+nanoparticles.">Nanoparticles in a box: a concept to isolate, store and re-use colloidal surfactant-free precious metal nanoparticles.</a> J. Mat. Chem. A. 5 (13), 6140-6145 (2017).</li></ol>

作者没有什么可透露的。

众所周知, 由 TF-RDE 技术测量的高表面积催化剂的 ORR 活性高度取决于催化剂薄膜的均匀性6,9,10,14,19.有几个小组报告了在 GC 电极上均匀催化剂薄膜的制备方法, 研究人员在进入该研究区时应仔细优化其干燥方法20。使用旋转方法19可使较厚的催化剂薄膜的涂层具有更大的灵活性, 而固定方法则具有多个电极可同时制备的优点。作为固定干燥方法的一个例子, 筱崎 et. 最近报告说, 均匀的催化剂薄膜是通过干燥催化剂墨水在 IPA 大气 10. 本协议中的催化剂薄膜的制备是基于它们的方法。然而, 催化剂油墨是干燥在一个湿润的气体流, 而不是静止的气氛 (协议 3.3.2)。这种改进方法的优点是, 通过改变涌泉中的 IPA 和水的比例, 可以很容易地调节干燥条件。图 8表示通过改变加湿条件来优化催化剂薄膜的均匀性。
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/57105/57105fig8.jpg"> 图 8: 在不同干燥条件的 GC 电极上制备的催化剂薄膜的照片.涌泉中异丙醇 (IPA) 与 H2O 的比值被改变以优化干燥条件。(a) 100% 投资促进机构, (b) 90% 个 ipa/10% H2O, (c) 80% ipa/20% H2o, (d) 70% ipa/30% H2O. (c) 在这种情况下, 最好的干燥条件, 因为最均匀的催化剂薄膜是在 GC 电极上制造的。<a href="//ecsource.jove.com/files/ftp_upload/57105/57105fig8large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
我们还发现, 根据文献14中的报道, 催化剂油墨的 pH 值是获得均匀催化剂薄膜的一个重要参数。图 9说明了不同 pH 值的催化剂油墨的不同稳定性。由于 HCl 是用于在协议1.3.3 中的 Pt NPs 的洗涤, 催化剂墨水通常变得酸性, 不用增加 KOH。酸性催化剂油墨不稳定, 大部分铂/丙催化剂粒子在超声波后1周内沉淀。中性墨水比酸性墨水更稳定, 尽管在底部看到一些沉淀。碱性油墨最稳定, 超声波后1周未见沉淀。这种 ph 依赖性的催化剂油墨的稳定性是解释的大小的泽塔电位, 变得更大的 ph 值为14。
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/57105/57105fig9.jpg"> 图 9: 不同 pH 值的催化剂油墨的照片:(左) ph ≈ 4, (中间) ph 值≈ 7, (右) ph 值≈10。照片是在超声波1周后拍摄的。酸性油墨的分散性比中性和碱性油墨的稳定性要低得多。
不仅催化剂油墨的稳定性, 而且所获得的催化剂薄膜的均匀性取决于催化剂油墨的 pH 值。当使用酸性油墨 (图 10a、d) 时, 可获得高团聚催化剂薄膜。虽然从中性墨水和碱性油墨 (图 10b, c) 制造的催化剂薄膜之间的眼睛没有明显的差别, 但 SEM 图像显示, 催化剂薄膜中存在一些团聚。从中性墨水获得, 而从碱性墨水获得的催化剂薄膜中没有明显的团聚 (图 10e, f)。
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/57105/57105fig10.jpg"> 图 10: 在纸张上传输的催化剂薄膜的照片 (c) 和 GC 电极上的催化剂薄膜的 SEM 图像 (d f).(a、d)由酸性 (ph ≈ 4) 油墨 (b、e) 制成的催化剂膜, 由中性 (ph ≈ 7) 墨水和 (c、f) 制成, 由碱性 (ph 值≈ 10) 油墨制备的催化剂薄膜。<a href="//ecsource.jove.com/files/ftp_upload/57105/57105fig10large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
除催化剂膜质量外, 扫描速率为4和细胞电阻补偿影响了 ORR 活性测定8。在我们的测量设置中, 没有 iR 补偿的细胞电阻通常在30Ω左右。通过使用恒电位仪的 iR 补偿(图11a、b), 它将减少到小于3Ω.在图 11c中比较了在 O2饱和电解质中测量并没有 iR 补偿的 LSVs。一个明显的潜在的转移由于细胞抵抗被看见在大约 0.9 V 的, 在那里 ORR 活动被评估.作为 LSV 的扫描速率, 我们选择了 50 mV s-1, 而其他组5更喜欢 20 mV s-1 , 而膜电极组件 (多边环境协定) 通常在稳态条件下4进行测试。一般而言, RDE 研究表明, 扫描速率越低, 测量就越容易受到可能的污染物的影响。在多边环境协定测试中, 应用了相当高的电流。特别是对于汽车应用, 高功率性能特别有趣的21。如果不应用在线 iR 补偿, 扫描电位将导致严重错误。
由于这些差异, 应谨慎地采取基于 TF RDE 测量的多边环境协定性能的直接预测。RDE 应该被看作是一种快速的方法来筛选测试质子交换膜燃料电池催化剂的固有的 ORR 活性, 而不是替代多边环境协定的测试。
<img alt="Figure 11" class="xfigimg" src="/files/ftp_upload/57105/57105fig11.jpg"> 图 11: iR 补偿对测量的影响.(a, b)"EC4 数据采集" 程序界面的截屏, 具有无红外补偿功能。(c) LSVs 测量的 O2饱和电解质与 ir 补偿 (红色) 和没有 ir 补偿 (灰色) (50 mV s-1, 1600 rpm, 后退地面减去)。<a href="//ecsource.jove.com/files/ftp_upload/57105/57105fig11large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
总过程在中汇总图 12。除了所讨论的标准表征方法外, 所获得的胶体 Pt NPs 悬浮剂和 pt/C 催化剂也可以用更先进的方法来研究, 如小角度 X 射线散射 (SAXS)22或 X 射线吸收光谱(XAS)23。
<img alt="Figure 12" class="xfigimg" src="/files/ftp_upload/57105/57105fig12.jpg"> 图 12: 实验步骤概述.文中给出了该协议各实验步骤的相应表征方法和可控参数。透射电子显微镜, SAXS = 小角度 x 射线散射, EXAFS = 扩展 x 射线吸收精细结构, XANES = x 射线吸收精细结构, ICP-MS = 电感耦合等离子质谱, dl = 动态光散射, CCD =电荷耦合器件, SEM = 扫描电镜。<a href="//ecsource.jove.com/files/ftp_upload/57105/57105fig12large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

随着风能或太阳能等可再生能源的日益使用, 需要有能力储存和重新转换大量的电能。在这方面, 应用化学能源载体, 如氢气, 是一个有希望的途径1。水电解可以从过剩的电能中产生氢气, 而 PEMFCs 有效地将氢气转化为电能。然而, 对于大规模应用, 如汽车, PEMFCs 的贵金属 (铂) 含量需要大幅度降低, 以降低成本。在科学文献中, 提出了几种催化剂系统2 , 据报道, 这些体系具有满足这些要求的潜力, 这些需求基于 TF RDE 半细胞测试3。
TF-RDE 测量在质子交换膜燃料电池的研究中变得非常普遍, 现在被用作比较不同的质子交换膜燃料电池催化剂的标准方法。然而, 对于类似的催化剂, 氧还原反应 (ORR) 活性或电化学表面区域 (欧洲) 的显著差异通常由不同的研究组4报告。因此, 几个研究小组致力于改进实验程序, 并确定如何测试质子交换膜燃料电池催化剂5的最佳实践程序。首先, 催化剂加载的因素, 参考电极的污染, iR 补偿,等被突出显示6,7,8;近年来, 催化剂膜性能对性能的影响集中在9、10上。例如, 可以看出, ORR 活性和欧洲依赖于催化剂的油墨成分, 这反过来又影响了催化剂膜在玻璃碳 (GC) 电极上的均匀性。观察到的铂表面积在添加异丙醇后对催化剂墨水的增加尤其令人惊讶, 但这些结果表明, 碳支持润湿的重要性。另一个重要的 (和相关的) 因素是大众运输。由于电解质11、12、13中的低气体溶解度, TF RDE 被限制为低电流密度。因此, 通常假定在这种极薄的催化剂层 (ca 1 µm) 中, 反应物的质量运输起着有限的作用。然而, 在最近的工作中, 它表明, 油墨 pH 值的调整, 导致在国产催化剂中的 ORR 活性的显著增加14。这些例子突出表明, 在 TF RDE 测量中, 需要仔细的控制, 而且根据催化剂的不同, 可能很难定义一个标准测试协议/配方。
因此, 在所提出的工作中, 我们讨论了一步一步的过程中合成和测试标准的 Pt/C 燃料电池催化剂。该工艺包括催化剂的合成、表征、油墨的制备和调整以及电化学 TF-RDE 测量。该程序的目的是提高意识有关的某些来源的错误和实验缺陷, 以及提供一个可能的 Pt/C 基准催化剂的配方。

<table>
	<tbody>
		<tr>
			<td>Ethylene glycol</td>
			<td>Sigma-Aldrich</td>
			<td>293237-1L</td>
			<td>99.8%</td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Fisher Chemical</td>
			<td>AC134070010</td>
			<td>98%</td>
		</tr>
		<tr>
			<td>Hexachloroplatinic(IV) acid hexahydrate</td>
			<td>Alfa Aesar</td>
			<td>11051</td>
			<td>99.9%</td>
		</tr>
		<tr>
			<td>Hydrochloric acid</td>
			<td>Merck</td>
			<td>1003171000</td>
			<td>37%</td>
		</tr>
		<tr>
			<td>Nitric acid</td>
			<td>Any</td>
			<td></td>
			<td>60%</td>
		</tr>
		<tr>
			<td>Sulfuric acid</td>
			<td>Any</td>
			<td></td>
			<td>96%</td>
		</tr>
		<tr>
			<td>Perchloric acid</td>
			<td>Merck</td>
			<td>1005170250</td>
			<td>70%, Suprapur</td>
		</tr>
		<tr>
			<td>Potassium hydroxide hydrate</td>
			<td>Merck</td>
			<td>1050020500</td>
			<td>99.995%, Suprapur</td>
		</tr>
		<tr>
			<td>Tin(II) chloride dihydrate</td>
			<td>Sigma-Aldrich</td>
			<td>31669-100G</td>
			<td>&#62;98%</td>
		</tr>
		<tr>
			<td>Platinum standard for AAS</td>
			<td>Sigma-Aldrich</td>
			<td>47037-100ML</td>
			<td>1000 mg/L &#177;4 mg/L</td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Alfa Aesar</td>
			<td>30698</td>
			<td>99.5+%</td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>Alfa Aesar</td>
			<td>36644</td>
			<td>99.5%</td>
		</tr>
		<tr>
			<td>Carbon black</td>
			<td>Cabot</td>
			<td>Vulcan XC 72R</td>
			<td></td>
		</tr>
		<tr>
			<td>46 wt.% Pt/C</td>
			<td>Tanaka Kikinzoku Kogyo</td>
			<td>TEC10E50E</td>
			<td></td>
		</tr>
		<tr>
			<td>Ar gas</td>
			<td>Air Liquide</td>
			<td></td>
			<td>99.999%</td>
		</tr>
		<tr>
			<td>O2 gas</td>
			<td>Air Liquide</td>
			<td></td>
			<td>99.999%</td>
		</tr>
		<tr>
			<td>CO gas</td>
			<td>Air Liquide</td>
			<td></td>
			<td>99.97%</td>
		</tr>
		<tr>
			<td>H2 gas</td>
			<td>Air Liquide</td>
			<td></td>
			<td>99.999%</td>
		</tr>
		<tr>
			<td>Microwave reactor</td>
			<td>CEM</td>
			<td>Discover SP</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Corning</td>
			<td>6759</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotary evaporator</td>
			<td>KNF</td>
			<td>RC600</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultrasonic bath</td>
			<td>Qualilab</td>
			<td>USR 54 H</td>
			<td>35 kHz, 160/320 W</td>
		</tr>
		<tr>
			<td>Filter paper</td>
			<td>Albet</td>
			<td>DP595 055</td>
			<td>Retention rate 4-7 &#181;m, &#966;55 mm</td>
		</tr>
		<tr>
			<td>Crucible</td>
			<td>VWR</td>
			<td>459-0202</td>
			<td>12 mL</td>
		</tr>
		<tr>
			<td>Lid for crucible</td>
			<td>VWR</td>
			<td>459-0216</td>
			<td>&#966;35 mm</td>
		</tr>
		<tr>
			<td>pH meter</td>
			<td>VWR</td>
			<td>Symphony SP70P</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass electrode (for pH meter)</td>
			<td>Mettler Toledo</td>
			<td>InLab Routine</td>
			<td></td>
		</tr>
		<tr>
			<td>Light scattering</td>
			<td>Anton Paar</td>
			<td>Litesizer</td>
			<td></td>
		</tr>
		<tr>
			<td>TEM microscope</td>
			<td>FEI</td>
			<td>Tecani Spirit</td>
			<td></td>
		</tr>
		<tr>
			<td>TEM grid</td>
			<td>Quantifoil</td>
			<td>N1-C73nCu20-01</td>
			<td>Classic carbon film, Cu 200 mesh</td>
		</tr>
		<tr>
			<td>TEM grid</td>
			<td>Quantifoil</td>
			<td></td>
			<td>Classic holey carbon film, Cu 200 mesh</td>
		</tr>
		<tr>
			<td>TEM grid</td>
			<td>Quantifoil</td>
			<td>N1-C74nCu20-01</td>
			<td>Classic lacey carbon film, Cu 200 mesh</td>
		</tr>
		<tr>
			<td>UV-vis spectrophotometer</td>
			<td>Varian</td>
			<td>CARY 5E</td>
			<td></td>
		</tr>
		<tr>
			<td>Saturated calomel electrode</td>
			<td>Schott</td>
			<td>B3510+</td>
			<td></td>
		</tr>
		<tr>
			<td>Perfluorinated membrane</td>
			<td>Fuel Cell Store</td>
			<td>591239</td>
			<td>Nafion 117</td>
		</tr>
		<tr>
			<td>RDE rotator</td>
			<td>Raiometer Analytical</td>
			<td>EDI101</td>
			<td></td>
		</tr>
		<tr>
			<td>Potentiostat</td>
			<td>Nordic Electrochemisty</td>
			<td>ECi 200</td>
			<td></td>
		</tr>
		<tr>
			<td>Control and data acquisition program</td>
			<td>Nordic Electrochemisty</td>
			<td>EC4 DAQ</td>
			<td></td>
		</tr>
		<tr>
			<td>Data analysis program</td>
			<td>Nordic Electrochemisty</td>
			<td>EC4 VIEW</td>
			<td></td>
		</tr>
	</tbody>
</table>

on the preparation and testing of fuel cell catalysts using the thin film rotating disk electrode method

我们提出了一步一步的教程, 准备质子交换膜燃料电池 (PEMFC) 催化剂, 包括铂纳米粒子 (NPs) 支持的高表面碳, 并测试其性能的薄膜旋转盘电极 (TF-RDE)测量.RDE 方法广泛应用于催化剂筛选;然而, 在研究小组中, 衡量的表现有时相差很大。这些不确定性阻碍了新的催化剂材料的发展, 因此, 一些作者讨论了可能的最佳做法方法和基准的重要性。
视觉教程突出了 Pt/C 催化剂的 TF-RDE 测试中可能存在的缺陷。介绍了一种用于评价标准 pt/C 催化剂的合成和测试协议, 可与多晶 pt 圆盘作为基准催化剂一起使用。特别是, 本研究着重介绍了玻璃碳 (GC) 电极上的催化剂膜的性能如何影响 TF-RDE 测试的测量性能。要获得薄、均匀的催化剂膜, 不仅催化剂的制备, 而且油墨的沉积和干燥过程是必不可少的。证明了油墨 pH 值的调整可能是必要的, 以及如何使用简单的控制测量来检查胶片质量。一旦获得可重现的 TF-RDE 测量, 确定铂负载的催化剂支持 (表示为 Pt wt%) 和电化学表面面积是必要的正常化的反应速率, 以表面面积或 Pt 质量。对于表面面积的测定, 所谓 CO 剥离, 或氢 underpotential 沉积 (Hupd) 电荷的测定是标准的。对于 pt 负载的测定, 介绍了一种使用王水中的消化方法, 随后将 pt (IV) 转换为 pt (II) 和紫外可见光测量的简单而廉价的程序.

Pt NPs 的暗褐色, 胶体悬浮是从协议部分 1.1 (图 1, 左) 获得的。胶体悬浮液稳定性好, 可贮存1月以上, 无降水。通过降低氢氧化钠浓度18合成较大的 Pt NPs。但是, 通过降低碱液浓度, 胶体悬浮液的稳定性降低。作为一个极端的例子, 当 pt 前驱体在如没有氢氧化钠 (图 1) 加热时, 就得到了完全凝聚的 pt NPs。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57105/57105fig1.jpg"> 图 1: Pt NPs 的胶体悬浮物的照片 (如).左)通过1.1 号协议获得了良好分散的 Pt NPs。权利)在无氢氧化钠的情况下, 通过加热 pt 前驱物获得的团聚 pt 核动力源。
良好分散的 Pt/C 催化剂是从协议部分1.2 获得的, 如图 2a所示。当使用较不稳定的胶体悬浮液时, 采用较大 pt nps 的例如, 可以观察到 pt 核动力源在碳支持上的显著聚集 (图 2b)。
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57105/57105fig2.jpg"> 图 2: 透射电镜图像 50 .% Pt/火神催化剂.(a) 2 纳米 Pt NPs 在碳支架上分布良好。(b) 4 纳米 Pt NPs 在碳支架上结块。
在王水 (协议 2.4) 中测定铂浓度的紫外-可见光测量的代表性结果显示在 图 3a中。当 SnCl2添加到王水示例中时, 王水中的 pt 将从 pt (IV) 降低到 pt (II), 导致黄色色溶液. 图 3b是从图 3a中的光谱中获得的校准曲线。从这个校准曲线, 样品混合物中的 Pt 浓度确定为 3.68 ppm。
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57105/57105fig3.jpg"> 图 3: 测定水中铂浓度的紫外-可见光测量的代表性结果.(a) 在添加 Pt 标准溶液 (5-20 µL) 之前和之后, 使用 SnCl2的王水样本的紫外可见光谱。(b) 通过绘制 402 nm 的吸光度和 680 nm 的吸光度与添加 Pt 的浓度之间的差异来获得校准曲线。样品溶液中的 Pt 浓度由标定曲线的 x 截距确定。<a href="//cloudflare.jove.com/files/ftp_upload/57105/57105fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
图 4 a b是在 GC 电极上按照3.2 号协议制作的均匀催化剂薄膜的典型例子。GC 电极的整个表面均匀地覆盖在没有任何显著团聚的催化剂膜上。图 4cd 是典型的非均匀催化剂薄膜, 它是通过在空气中干燥催化剂墨水来制备的。催化剂团聚在 GC 电极的边缘, 形成所谓的咖啡环19。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57105/57105fig4.jpg"> 图 4: 在 GC 电极上制备的均匀和非均匀催化剂薄膜的照片和 SEM 图像.(a, b)遵循该协议制备的均匀催化剂薄膜。(c、d)在空气中通过干燥催化剂墨水制成的 "咖啡环" 的非均匀催化剂薄膜。(a) 和 (c) 是催化剂薄膜的整体图片。(b) 和 (d) 是在 GC 磁盘边缘拍摄的催化剂薄膜的 SEM 图像。
图 5是在 H2饱和电解质中测量的循环伏安的一个示例, 用于校准参考电极电位 (协议 3.3.5)。在正向扫描中, 当前密度为0毫安厘米-2的电位的平均值, 以及负扫描定义为 "0 V vs"。
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57105/57105fig5.jpg"> 图 5: H2中的循环伏安用于校准潜在的参考电极 (50 mV-1, 1600 rpm) 的饱和电解质.当前密度为0毫安 cm-2的正向扫描和负向扫描定义为 0 V vs 可逆氢电极 (参见虚线红色线) 的电位平均值。
图 6中显示的是 Ar 饱和电解质和线性扫描伏安 (LSV) 在 O2饱和电解质中的循环伏安, 用于从 RDE 测量获得的 50 wt% Pt/火神催化剂 (协议3.3.7 和 3.3.8)。在协议步骤3.4.6 中有足够的清理周期后, 将获得图 6a中的红色 CV。当催化剂没有充分清洁时, Pt 氧化峰的肩部大约为 0.8 V, 比清洗干净的催化剂 (图 6a, 灰色 CV) 的肩膀要小。O2饱和电解质中 LSV 的形状对催化剂薄膜的质量非常敏感 (图 6b)。当催化剂薄膜在图 4a中相同时, O2扩散限流密度 (低于 0.8 V) 观察到-6 mA cm-2, LSV 曲线的肩部约 0.8 V 为锐 (图 6b, 红色)。另一方面, O2扩散限制电流密度较小, 当催化剂薄膜为非均匀时, LSV 曲线的肩部不太锋利, 如图 4c, 或者 GC 电极表面未完全覆盖催化剂薄膜。
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/57105/57105fig6.jpg"> 图 6: 用于 50 wt% Pt/火神催化剂的 "良好" 和 "坏" 伏安的典型示例.(a) Ar 饱和电解质中的循环伏安 (50 mV s-1)。(b) LSVs O2饱和电解质 (1600 rpm, 50 mV/秒, 正向扫描, 背景减去, iR 补偿)。<a href="//cloudflare.jove.com/files/ftp_upload/57105/57105fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
图 7中所示的循环伏安是在 Ar 饱和电解质中记录的, 其 Hupd区域表示 (a), 并带有剥离电荷的 CO 剥离伏安 (b)。这两种测量都获得了 50 wt% Pt/火神催化剂。从峰值下的区域计算出 Pt 表面积 (欧洲), 见步骤3.4.1。
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/57105/57105fig7.jpg"> 图 7: 具有代表性的循环伏安 (a) 和 CO 剥离伏安 (b) 用于 50 wt% Pt/火神催化剂 (50 mV s-1).Hupd电荷和 CO 剥离电荷分别在天空蓝色和粉红色中突出显示。<a href="//cloudflare.jove.com/files/ftp_upload/57105/57105fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
在表 1中总结了 50 wt% Pt/火神催化剂的 RDE 测量结果 (欧洲、ORR 特定活动和 0.9 V 的质量活动)。对具有类似 pt 颗粒尺寸和类似 pt 载荷的商用铂/丙催化剂的结果也作了说明。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td></td>
			<td>Pt 粒度</td>
			<td>欧洲</td>
			<td>特定活动</td>
			<td>质量活动</td>
		</tr>
<tr>
<td></td>
			<td>毫微米]</td>
			<td>[m2 g-1Pt]</td>
			<td>[µA cm-2Pt]</td>
			<td>[A g-1Pt]</td>
		</tr>
<tr>
<td>50 .% Pt/火神</td>
			<td>2</td>
			<td>102 @ 3</td>
			<td>852 @ 66</td>
			<td>879 @ 82</td>
		</tr>
<tr>
<td>46磅 .% (TKK)</td>
			<td>2-3</td>
			<td>93 @ 3</td>
			<td>738 @ 30</td>
			<td>683 @ 31</td>
		</tr>
</tbody></table>表 1:50 wt% pt/火神催化剂和商用 46 wt% pt/C 催化剂的 TF-RDE 测量结果摘要.测量值以标准偏差显示。欧洲 = 电化学表面面积, ORR = 氧气还原反应, TKK = 田中 Kikinzoku 工业。

Watch this Scientific Journal Video about On the Preparation and Testing of Fuel Cell Catalysts Using the Thin Film Rotating Disk Electrode Method at JoVE.com

On the Preparation and Testing of Fuel Cell Catalysts Using the Thin Film Rotating Disk Electrode Method

用薄膜旋转圆盘电极法制备和测试燃料电池催化剂的研究

制备和测试 Pt/C 燃料电池催化剂是在科学界对重现性和最佳实践的持续讨论。在提出的工作中, 我们打算提出一步一步的教程, 以建立和测试 Pt/C 催化剂, 这可以作为一个新的催化剂系统的基准。

We present a step-by-step tutorial to prepare proton exchange membrane fuel cell (PEMFC) catalysts, consisting of Pt nanoparticles (NPs) supported on a ...

on-preparation-testing-fuel-cell-catalysts-using-thin-film-rotating

Research

JoVE Journal

Environment

21.7K 次观看.  University of Copenhagen. 制备和测试 Pt/C 燃料电池催化剂是在科学界对重现性和最佳实践的持续讨论。在提出的工作中, 我们打算提出一步一步的教程, 以建立和测试 Pt/C 催化剂, 这可以作为一个新的催化剂系统的基准。

视频: On the Preparation and Testing of Fuel Cell Catalysts Using the Thin Film Rotating Disk Electrode Method

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays

Much of the nutrient cycling and carbon processing in natural environments occurs through the activity of extracellular enzymes released by microorganisms. Thus, measurement of the activity of these extracellular enzymes can give insights into the rates of ecosystem level processes, such as organic matter decomposition or nitrogen and phosphorus mineralization. Assays of extracellular enzyme activity in environmental samples typically involve exposing the samples to artificial colorimetric or fluorometric substrates and tracking the rate of substrate hydrolysis. Here we describe microplate based methods for these procedures that allow the analysis of large numbers of samples within a short time frame. Samples are allowed to react with artificial substrates within 96-well microplates or deep well microplate blocks, and enzyme activity is subsequently determined by absorption or fluorescence of the resulting end product using a typical microplate reader or fluorometer. Such high throughput procedures not only facilitate comparisons between spatially separate sites or ecosystems, but also substantially reduce the cost of such assays by reducing overall reagent volumes needed per sample.

Microplate based procedures are described for the colorimetric or fluorometric analysis of extracellular enzyme activity. These procedures allow for the rapid assay of such activity in large numbers of environmental samples within a manageable time frame.

在使用高通量微孔板测定水，土壤，沉积物和微生物测定胞外酶活性的

Much of the nutrient cycling and carbon  processing in natural environments occurs through the activity of extracellular  enzymes released by ...

科研

环境科学

Preparation and Testing of Plant Seed Meal-based Wood Adhesives

Recently, the interest in plant seed meal-based products as wood adhesives has steadily increased, as these plant raw materials are considered renewable and environment-friendly. These natural products may serve as alternatives to petroleum-based adhesives to ease environmental and sustainability concerns. This work demonstrates the preparation and testing of the plant seed-based wood adhesives using cottonseed and soy meal as raw materials. In addition to untreated meals, water washed meals and protein isolates are prepared and tested. Adhesive slurries are prepared by mixing a freeze-dried meal product with deionized water (3:25 w/w) for 2 hr. Each adhesive preparation is applied to one end of 2 wood veneer strips using a brush. The tacky adhesive coated areas of the wood veneer strips are lapped and glued by hot-pressing. Adhesive strength is reported as the shear strength of the bonded wood specimen at break. Water resistance of the adhesives is measured by the change in shear strength of the bonded wood specimens at break after water soaking. This protocol allows one to assess plant seed-based agricultural products as suitable candidates for substitution of synthetic-based wood adhesives. Adjustments to the adhesive formulation with or without additives and bonding conditions could optimize their adhesive properties for various practical applications.

To facilitate the effort in seeking more economic and environment-friendly formulations of natural product-based wood adhesives, this work demonstrates the preparation and testing of plant seed-based wood adhesives. This protocol allows one to assess plant seed-based agricultural products as suitable candidates for the substitution of synthetic-based wood adhesives.

准备和植物种子膳食为基础的木材胶粘剂的测试

Recently, the interest in plant seed meal-based products as wood adhesives has steadily increased, as these plant raw materials are considered renewable ...

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study evaporation under various surface boundary conditions to improve our current understanding and characterization of this multiphase phenomenon as well as to validate numerical heat and mass transfer theories that couple Navier-Stokes flow in the atmosphere and Darcian flow in the porous media. Experimental data were collected using a unique soil tank apparatus interfaced with a small climate controlled wind tunnel. The experimental apparatus was instrumented with a suite of state of the art sensor technologies for the continuous and autonomous collection of soil moisture, soil thermal properties, soil and air temperature, relative humidity, and wind speed. This experimental apparatus can be used to generate data under well controlled boundary conditions, allowing for better control and gathering of accurate data at scales of interest not feasible in the field. Induced airflow at several distinct wind speeds over the soil surface resulted in unique behavior of heat and mass transfer during the different evaporative stages.

A protocol for the design and construction of a soil tank interfaced to a small climate controlled wind tunnel to study the effects of atmospheric forcings on evaporation is presented. Both the soil tank and wind tunnel are instrumented with sensor technologies for the continuous in situ measurement of environmental conditions.

在探索大气蒸发强迫的影响:大气边界层和浅地层的实验整合

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study ...

Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages include high potential yield, use of non-arable land and integration with waste streams. The nutrient requirements of a large-scale microalgae production system will require the coupling of cultivation systems with industrial waste resources, such as carbon dioxide from flue gas and nutrients from wastewater. Inorganic contaminants present in these wastes can potentially lead to bioaccumulation in microalgal biomass negatively impact productivity and limiting end use. This study focuses on the experimental evaluation of the impact and the fate of 14 inorganic contaminants (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn) on Nannochloropsis salina growth. Microalgae were cultivated in photobioreactors illuminated at 984 &#181;mol m-2 sec-1 and maintained at pH 7 in a growth media polluted with inorganic contaminants at levels expected based on the composition found in commercial coal flue gas systems. Contaminants present in the biomass and the medium at the end of a 7 day growth period were analytically quantified through cold vapor atomic absorption spectrometry for Hg and through inductively coupled plasma mass spectrometry for As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sb, Se, Sn, V and Zn. Results show N. salina is a sensitive strain to the multi-metal environment with a statistical decrease in biomass yieldwith the introduction of these contaminants. The techniques presented here are adequate for quantifying algal growth and determining the fate of inorganic contaminants.

Integration of microalgal cultivation with industrial flue gas will ultimately introduce heavy metals and other inorganic compounds into the growth media. This study presents a procedure used to determine the end fate and impact of heavy metals and inorganic contaminants on the growth of Nannochloropsis salina grown in photobioreactors.

重金属和微藻的产其他无机污染物的量化

Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, such as microalgae. Inherent advantages ...

Protocol for Microplastics Sampling on the Sea Surface and Sample Analysis

Microplastic pollution in the marine environment is a scientific topic that has received increasing attention over the last decade. The majority of scientific publications address microplastic pollution of the sea surface. The protocol below describes the methodology for sampling, sample preparation, separation and chemical identification of microplastic particles. A manta net fixed on an &#187;A frame&#171; attached to the side of the vessel was used for sampling. Microplastic particles caught in the cod end of the net were separated from samples by visual identification and use of stereomicroscopes. Particles were analyzed for their size using an image analysis program and for their chemical structure using ATR-FTIR and micro FTIR spectroscopy. The described protocol is in line with recommendations for microplastics monitoring published by the Marine Strategy Framework Directive (MSFD) Technical Subgroup on Marine Litter. This written protocol with video guide will support the work of researchers that deal with microplastics monitoring all over the world.

The protocol below describes the methodology for: microplastics sampling on the sea surface, separation of microplastic and chemical identification of particles. This protocol is in line with the recommendations for microplastics monitoring published by the MSFD Technical Subgroup on Marine Litter.

协议塑料微粒采样的海面和样品分析

Microplastic pollution in the marine environment is a scientific topic that has received increasing attention over the last decade. The majority of ...

Evaluating the Effect of Environmental Chemicals on Honey Bee Development from the Individual to Colony Level

The presence of pesticides in the beekeeping environment is one of the most serious problems that impacts the life of a honey bee. Pesticides can be brought back to the beehive after the bees have foraged on flowers that have been sprayed with pesticides. Pesticide contaminated food can be exchanged between workers which then feed larvae and therefore can potentially affect the development of honey bees. Thus, residual pesticides in the environment can become a chronic damaging factor to honey bee populations and gradually lead to colony collapse. In the presented protocol, honey bee feeding methods are described and applied to either an individual honey bee or to a colony. Here, the insect growth regulator (IGR) pyriproxyfen (PPN), which is widely used to control pest insects and is harmful to the development of honey bee larvae and pupae, is used as the pesticide. The presenting procedure can be applied to other potentially harmful chemicals or honeybee pathogens for further studies.

Herein we present a method to feed pesticide contaminated food to both an individual honey bee and a beehive colony. The procedure evaluates the pesticide effect on individual honey bees by in vivo feeding of basic larval diet and also on the natural condition of beehive colony.

从个体到群体度评价环境化学物质对蜜蜂发展的影响

The presence of pesticides in the beekeeping environment is one of the most serious problems that impacts the life of a honey bee. Pesticides can be ...

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

Dimethylated thioarsenicals such as dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV), which are produced by the metabolic pathway of dimethylarsinic acid (DMAV) thiolation, have been recently found in the environment as well as human organs. DMMTAV and DMDTAV can be quantified to determine the ecological effects of dimethylated thioarsenicals and their stability in environmental media. The synthesis method for these compounds is unstandardized, making replicating previous studies challenging. Furthermore, there is a lack of information about storage techniques, including storage of compounds without species transformation. Moreover, because only limited information about synthesis methods is available, there may be experimental difficulties in synthesizing standard chemicals and performing quantitative analysis. The protocol presented herein provides a practically modified synthesis method for the dimethylated thioarsenicals, DMMTAV and DMDTAV, and will help in the quantification of species separation analysis using high performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The experimental steps of this procedure were modified by focusing on the preparation of chemical reagents, filtration methods, and storage.

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

This article presents modified experimental protocols for dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV) synthesis, inducing dimethylarsinic acid (DMAV) thiolation through mixing of DMAV, Na2S, and H2SO4. The modified protocol provides an experimental guideline, thereby overcoming limitations of the synthesis steps that could have caused experimental failures in quantitative analysis.

使用 DMAv为环境应用 DMMTAv和 DMDTAv的准备: 合成、纯化和确认

Dimethylated thioarsenicals such as dimethylmonothioarsinic acid (DMMTAV) and dimethyldithioarsinic acid (DMDTAV), which are produced by the metabolic ...

The Effect of the Application of Thyme Essential Oil on Microbial Load During Meat Drying

Meat is a high protein meal that is used in the preparation of jerky, a popular food snack, where preservation and safety are important. To assure food safety and to extend the shelf life of meat and meat products, the use of either synthetic or natural preservatives have been applied to control and eliminate foodborne bacteria. A growing interest in the application of natural food additives for meat has increased. Microorganisms, such as Escherichia coli, contaminate meat and meat products, causing foodborne illnesses. Therefore, it is necessary to improve the meat conservation process. However, the use of essential oils when the meat is being dried has not been deeply studied. In this regard, there is an opportunity to increase the value of dried meat and reduce the risk of foodborne illnesses by applying essential oils during the drying process. In this protocol, we present a novel method of applying thyme essential oil (TEO) during meat drying, specifically in vapor form directly in a drying chamber. For evaluation, we use Minimal Inhibitory Concentration (MIC) to detect the number of harmful bacteria in the treated samples compared to raw samples. The preliminary results show that this method is a viable and alternative option to synthetic preservatives and that it significantly reduces microbial load in dried meat.

Microorganisms such as Escherichia coli that contaminate meat products cause foodborne illnesses. The use of essential oils in the meat drying process has not been deeply studied. Here, we present a novel method of applying thyme essential oil to meat during drying to reduce the microbial load in dried meat.

百里香精油应用于肉类干燥过程中微生物负荷的影响

Meat is a high protein meal that is used in the preparation of jerky, a popular food snack, where preservation and safety are important. To assure food ...

Protocol for Acute and Chronic Ecotoxicity Testing of the Turquoise Killifish Nothobranchius furzeri

The killifish Nothobranchius furzeri is an emerging model organism in the field of ecotoxicology and its applicability in acute and chronic ecotoxicity testing has been demonstrated. Overall, the sensitivity of the species to toxic compounds is in the range with, or higher than, that of other model species.
This work describes protocols for acute, chronic, and multigenerational bioassays of single and combined stressor effects on N. furzeri. Due to its short maturation time and life-cycle, this vertebrate model allows the study of endpoints such as maturation time and fecundity within four months. Transgenerational full life-cycle exposure trials can be performed in as little as 8 months. Since this species produces eggs that are drought-resistant and remain viable for years, the on-site culture of the species is not needed but individuals can be recruited when required. The protocols are designed to measure life-history traits (mortality, growth, fecundity, weight) and critical thermal maximum.

Protocol for Acute and Chronic Ecotoxicity Testing of the Turquoise Killifish Nothobranchius furzeri

In this work, we describe an acute, chronic and multigenerational bioassay to study the effects of single and combined stressors on the Turquoise killifish Nothobranchius furzeri. This protocol is designed to study life-history traits (mortality, growth, fecundity, weight) and critical thermal maximum.

绿松石鳉鱼的急性和慢性毒性测试协议Nothobranchius furzeri

The killifish Nothobranchius furzeri is an emerging model organism in the field of ecotoxicology and its applicability in acute and chronic ecotoxicity ...

Sample Preparation Method of Scanning and Transmission Electron Microscope for the Appendages of Woodboring Beetle

This report described sample preparation methods that scanning and transmission electron microscope observations, demonstrated by preparing appendages of the woodboring beetle, Chlorophorus caragana Xie &#38; Wang (2012), for both types of electron microscopy. The scanning electron microscopy (SEM) sample preparation protocol was based on sample chemical fixation, dehydration in a series of ethanol baths, drying, and sputter-coating. By adding Tween 20 (Polyoxyethylene sorbitan laurate) to the fixative and the wash solution, the insect body surface of woodboring beetle was washed more cleanly in SEM. This study&#39;s transmission electron microscopy (TEM) sample preparation involved a series of steps including fixation, ethanol dehydration, embedding in resin, positioning using fluorescence microscopy, sectioning, and staining. Fixative with Tween 20 enabled penetrate the insect body wall of woodboring beetle more easily than it would had been without Tween 20, and subsequently better fixed tissues and organs in the body, thus yielded clear transmission electron microscope observations of insect sensilla ultrastructures. The next step of this preparation was determining the positions of insect sensilla in the sample embedded in the resin block by using fluorescence microscopy to increase the precision of target sensilla positioning. This improved slicing accuracy.

In order to observe ultrastructure of insect sensilla, scanning and transmission electron microscopy (SEM and TEM, respectively) sample preparation protocol were presented in the study. Tween 20 was added into the fixative to avoid sample deformation in SEM. Fluorescence microscopy was helpful for improving slicing accuracy in TEM.

木钻甲虫附着物扫描和透射电子显微镜的样品制备方法

This report described sample preparation methods that scanning and transmission electron microscope observations, demonstrated by preparing appendages of ...