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

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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.bdigitaluss.remotexs.co/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.bdigitaluss.remotexs.co/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.bdigitaluss.remotexs.co/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.bdigitaluss.remotexs.co/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>&gt;98%</td></tr><tr><td>Platinum standard for AAS</td><td>Sigma-Aldrich</td><td>47037-100ML</td><td>1000 mg/L &amp;plusmn;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>O&lt;sub&gt;2&lt;/sub&gt; 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>H&lt;sub&gt;2&lt;/sub&gt; 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 &amp;micro;m, &amp;phi;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>&amp;phi;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.bdigitaluss.remotexs.co/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.bdigitaluss.remotexs.co/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.bdigitaluss.remotexs.co/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

Universidad San Sebastian

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

Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.

在固体氧化物燃料电池电极表面的探测和测绘

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen ...

科研

工程学

Self-standing Electrochemical Set-up to Enrich Anode-respiring Bacteria On-site

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be critical for microbial energy production and persistence in many subsurface environments, especially those lacking soluble terminal electron acceptors. While EET-capable microbes have been successfully isolated from various environments, the diversity of bacteria capable of EET is still poorly understood, especially in difficult-to-sample, low energy or extreme environments, such as many subsurface ecosystems. Here, we describe an on-site electrochemical system to enrich EET-capable bacteria using an anode as a respiratory terminal electron acceptor. This anode is connected&#160;to a cathode capable of&#160;catalyzing abiotic oxygen reduction. Comparing this approach with electrocultivation methods that use a potentiostat for poising the electrode potential, the two-electrode system does not require an external power source. We present an example of our on-site enrichment utilized in an alkaline pond at the Cedars, a terrestrial serpentinization site in Northern California. Prior attempts to cultivate mineral reducing bacteria were unsuccessful, which is likely due to the low-biomass nature of this site and/or the low relative abundance of metal reducing microbes. Prior to implementing our two-electrode enrichment, we measured the vertical profile of dissolved oxygen concentration. This allowed us to place the carbon felt anode and platinum-electroplated carbon felt cathode at depths that would support anaerobic and aerobic processes, respectively. Following on-site incubation, we further enriched the anodic electrode in the laboratory and confirmed&#160;a distinct microbial community compared to the surface-attached or biofilm communities normally observed at the Cedars. This enrichment subsequently led to the isolation of the first electrogenic microbe from the Cedars. This method of on-site microbial enrichment has the potential to greatly enhance the isolation of EET-capable bacteria from low biomass or difficult to sample habitats.

On-site microbial enrichment or in situ cultivation techniques can facilitate the isolation of difficult-to-culture microbial taxa, especially from low-biomass or geochemically extreme environments. Here, we describe an electrochemical set-up without using an external power source to enrich microbial strains that are capable of extracellular electron transport (EET).

自立电化学建立富集阳极 respiring 菌现场

Anaerobic respiration coupled with electron transport to insoluble minerals (referred to as extracellular electron transport [EET]) is thought to be ...

环境科学

Combustion Characterization and Model Fuel Development for Micro-tubular Flame-assisted Fuel Cells

Combustion based power generation has been accomplished for many years through a number of heat engine systems. Recently, a move towards small scale power generation and micro combustion as well as development in fuel cell research has created new means of power generation that combine solid oxide fuel cells with open flames and combustion exhaust. Instead of relying upon the heat of combustion, these solid oxide fuel cell systems rely on reforming of the fuel via combustion to generate syngas for electrochemical power generation. Procedures were developed to assess the combustion by-products under a wide range of conditions. While theoretical and computational procedures have been developed for assessing fuel-rich combustion exhaust in these applications, experimental techniques have also emerged. The experimental procedures often rely upon a gas chromatograph or mass spectrometer analysis of the flame and exhaust to assess the combustion process as a fuel reformer and means of heat generation. The experimental techniques developed in these areas have been applied anew for the development of the micro-tubular flame-assisted fuel cell. The protocol discussed in this work builds on past techniques to specify a procedure for characterizing fuel-rich combustion exhaust and developing a model fuel-rich combustion exhaust for use in flame-assisted fuel cell testing. The development of the procedure and its applications and limitations are discussed.

A protocol for creating a model fuel-rich combustion exhaust is developed through combustion characterization and is applied for micro-tubular flame-assisted fuel cell testing and research.

燃烧特性参数和模型燃料开发的微型管状火焰辅助燃料电池

Combustion based power generation has been accomplished for many years through a number of heat engine systems. Recently, a move towards small scale power ...

Synthesis and Testing of Supported Pt-Cu Solid Solution Nanoparticle Catalysts for Propane Dehydrogenation

A convenient method for the synthesis of bimetallic Pt-Cu catalysts and performance tests for propane dehydrogenation and characterization are demonstrated here. The catalyst forms a substitutional solid solution structure, with a small and uniform particle size around 2 nm. This is realized by careful control over the impregnation, calcination, and reduction steps during catalyst preparation and is identified by advanced in situ synchrotron techniques. The catalyst propane dehydrogenation performance continuously improves with increasing Cu:Pt atomic ratio.

A convenient method for the synthesis of 2 nm supported bimetallic nanoparticle Pt-Cu catalysts for propane dehydrogenation is reported here. In situ synchrotron X-ray techniques allow for the determination of the catalyst structure, which is typically unobtainable using laboratory instruments.

用于丙烷脱氢的负载型Pt-Cu固溶体纳米粒子催化剂的合成与测试

A convenient method for the synthesis of bimetallic Pt-Cu catalysts and performance tests for propane dehydrogenation and characterization are ...

化学

Simple Methods for the Preparation of Non-noble Metal Bulk-electrodes for Electrocatalytic Applications

The rock material pentlandite with the composition Fe4.5Ni4.5S8 was synthesized via high temperature synthesis from the elements. The structure and composition of the material was characterized via powder X-ray diffraction (PXRD), M&#246;ssbauer spectroscopy (MB), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and energy dispersive X-ray spectroscopy (EDX). Two preparation methods of pentlandite bulk electrodes are presented. In the first approach a piece of synthetic pentlandite rock is directly contacted via a wire ferrule. The second approach utilizes pentlandite pellets, pressed from finely ground powder, which is immobilized in a Teflon casing. Both electrodes, whilst being prepared by an additive-free method, reveal high durability during electrocatalytic conversions in comparison to common drop-coating methods. We herein showcase the striking performance of such electrodes to accomplish the hydrogen evolution reaction (HER) and present a standardized method to evaluate the electrocatalytic performance by electrochemical and gas chromatographic methods. Furthermore, we report stability tests via potentiostatic methods at an overpotential of 0.6 V to explore the material limitations of the electrodes during electrolysis under industrial relevant conditions.

A facile preparation method of electrodes using the bulk material Fe4.5Ni4.5S8 is presented. This method provides an alternative technique to conventional electrode fabrication and describes prerequisites for unconventional electrode materials including a straightforward electrocatalytic testing method.

用于制备用于电催化应用的非贵金属体电极的简单方法

The rock material pentlandite with the composition Fe4.5Ni4.5S8 was synthesized via high temperature synthesis from the elements. The structure and ...

Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen reduction reaction. Spontaneous galvanic displacement was used to deposit Pt layers onto Ni nanowire substrates. The synthesis approach produced catalysts with high specific activities and high Pt surface areas. Hydrogen annealing improved Pt and Ni mixing and specific activity. Acid leaching was used to preferentially remove Ni near the nanowire surface, and oxygen annealing was used to stabilize near-surface Ni, improving durability and minimizing Ni dissolution. These protocols detail the optimization of each post-synthesis processing step, including hydrogen annealing to 250 &#176;C, exposure to 0.1 M nitric acid, and oxygen annealing to 175 &#176;C. Through these steps, Pt-Ni nanowires produced increased activities more than an order of magnitude than Pt nanoparticles, while offering significant durability improvements. The presented protocols are based on Pt-Ni systems in the development of fuel cell catalysts. These techniques have also been used for a variety of metal combinations, and can be applied to develop catalysts for a number of electrochemical processes.

&#160; The protocol describes the synthesis and electrochemical testing of platinum-nickel nanowires. Nanowires were synthesized by the galvanic displacement of a nickel nanowire template. Post-synthesis processing, including hydrogen annealing, acid leaching, and oxygen annealing were used to optimize nanowire performance and durability in the oxygen reduction reaction.

铂镍纳米线的合成及减氧性能优化

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen ...

A Guide to Concentration Alternating Frequency Response Analysis of Fuel Cells

An experimental setup capable of generating a periodic concentration input perturbation of oxygen was used to perform concentration-alternating frequency response analysis (cFRA) on proton-exchange membrane (PEM) fuel cells. During cFRA experiments, the modulated concentration feed was sent to the cathode of the cell at different frequencies. The electric response, which can be cell potential or current depending on the control applied on the cell, was registered in order to formulate a frequency response transfer function. Unlike traditional electrochemical impedance spectroscopy (EIS), the novel cFRA methodology makes it possible to separate the contribution of different mass transport phenomena from the kinetic charge transfer processes in the frequency response spectra of the cell. Moreover, cFRA is able to differentiate between varying humidification states of the cathode. In this protocol, the focus is on the detailed description of the procedure to perform cFRA experiments. The most critical steps of the measurements and future improvements to the technique are discussed.

We present a protocol for concentration alternating frequency response analysis of fuel cells, a promising new method of studying fuel cell dynamics.

燃料电池浓度交替频率响应分析指南

An experimental setup capable of generating a periodic concentration input perturbation of oxygen was used to perform concentration-alternating frequency ...

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity in aqueous CO2 reduction. Different from traditional metal nanocrystals, the synthesis of metal single atoms involves a matrix material that can confine those single atoms and prevent them from aggregation. We report an electrospinning and thermal annealing method to prepare Ni single atoms dispersed and coordinated in a graphene shell, as active centers for CO2 reduction to CO. During the synthesis, N dopants play a critical role in generating graphene vacancies to trap Ni atoms. Aberration-corrected scanning transmission electron microscopy and three-dimensional atom probe tomography were employed to identify the single Ni atomic sites in graphene vacancies. Detailed setup of electrochemical CO2 reduction apparatus coupled with an on-line gas chromatography is also demonstrated. Compared to metallic Ni, Ni single atom catalyst exhibit dramatically improved CO2 reduction and suppressed H2 evolution side reaction.

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Here, we present a protocol for the synthesis and electrochemical testing of transition metal single atoms coordinated in graphene vacancies as active centers for selective carbon dioxide reduction to carbon monoxide in aqueous solutions.

电化学 CO2还原的过渡金属单原子催化剂的合成及性能表征

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity ...

Electrochemical Roughening of Thin-Film Platinum Macro and Microelectrodes

This protocol demonstrates a method for electrochemical roughening of thin-film platinum electrodes without preferential dissolution at grain boundaries of the metal. Using this method, a crack free, thin-film macroelectrode surface with up to 40 times increase in active surface area was obtained. The roughening is easy to do in a standard electrochemical characterization laboratory and incudes the application of voltage pulses followed by extended application of a reductive voltage in a perchloric acid solution. The protocol includes the chemical and electrochemical preparation of both a macroscale (1.2 mm diameter) and microscale (20 &#181;m diameter) platinum disc electrode surface, roughening the electrode surface and characterizing the effects of surface roughening on electrode active surface area. This electrochemical characterization includes cyclic voltammetry and impedance spectroscopy and is demonstrated for both the macroelectrodes and the microelectrodes. Roughening increases electrode active surface area, decreases electrode impedance, increases platinum charge injection limits to those of titanium nitride electrodes of same geometry and improves substrates for adhesion of electrochemically deposited films.

This protocol demonstrates a method for electrochemical roughening of thin-film platinum electrodes without preferential dissolution at grain boundaries. The electrochemical techniques of cyclic voltammetry and impedance spectroscopy are demonstrated to characterize these electrode surfaces.

薄膜铂金宏观和微电极的电化学粗加工

This protocol demonstrates a method for electrochemical roughening of thin-film platinum electrodes without preferential dissolution at grain boundaries ...

探索用于过氧化氢燃料电池的创新 3D 电极

Membraneless Hydrogen Peroxide Fuel Cells as a Promising Clean Energy Source

In an in-depth investigation of membraneless hydrogen peroxide-based fuel cells (H2O2 FCs), hydrogen peroxide (H2O2), a carbon-neutral compound, is demonstrated to undergo electrochemical decomposition to produce H2O, O2, and electrical energy. The unique redox properties of H2O2 position it as a viable candidate for sustainable energy applications. The proposed membraneless design addresses the limitations of conventional fuel cells, including fabrication complexities and design challenges. A novel three-dimensional electrode, synthesized via electroplating techniques, is introduced. Constructed from Au-electroplated carbon fiber cloth combined with Ni-foam, this electrode showcases enhanced electrochemical reaction kinetics, leading to an increased power density for H2O2 FCs. The performance of fuel cells is intricately linked to the pH levels of the electrolyte solution. Beyond FC applications, such electrodes hold potential in portable energy systems and as high surface area catalysts. This study emphasizes the significance of electrode engineering in optimizing the potential of H2O2 as an environmentally friendly energy source.

作者聚焦:用于过氧化氢燃料电池的金电镀碳纤维布电极的设计和评估 

This protocol introduces the design and evaluation of innovative three-dimensional electrodes for hydrogen peroxide fuel cells, utilizing Au-electroplated carbon fiber cloth and Ni-foam electrodes. The research findings highlight hydrogen peroxide's potential as a promising candidate for sustainable energy technologies.

无膜双氧水燃料电池作为一种有前途的清洁能源

In an in-depth investigation of membraneless hydrogen peroxide-based fuel cells (H2O2 FCs), hydrogen peroxide (H2O2), a carbon-neutral compound, is ...