根据合同号 DE-AC36-08GO28308 到 NREL, 美国能源部、能源效率和可再生能源办公室提供了财政支助。

1. 铂镍纳米线的合成
<ol><li>要开始置换过程, 在水中悬浮镍纳米线模板并将其加热到90摄氏度。<ol>
<li>在50毫升离心管中加入40毫克的商用, 镍纳米线到20毫升的去离子水。油脂实验5分钟。 注: 纳米线直径约为150-250 纳米, 长度为100-200 µm。</li>
		<li>将悬浮纳米线转移到250毫升的玻璃圆底烧瓶中, 加入60毫升的去离子水。在矿物油浴中加热烧瓶到90°c。搅拌反应混合物在 500 rpm 与聚四氟乙烯桨连接到玻璃轴和电动搅拌器。</li>
	</ol>
</li>
	<li>由自发电偶位移形成 Pt 镍纳米线。<ol>
<li>添加8.1 毫克的 tetrachloroplatinate 钾到15毫升的去离子水。将该解决方案添加到20毫升注射器上, 其端部附有大约8厘米0.318 厘米聚氨酯基油管。将注射器放在自动注射器泵中, 并将其设置为1毫升/分钟。</li>
		<li>启动注射器泵, 并允许泵添加解决方案的圆底烧瓶超过15分钟. 将烧瓶加热90摄氏度, 2 小时。</li>
		<li>离心溶液在 2500 x g 15 分钟, 并倒入上清到废物流。并用重悬 solidswith 浴超声波 (大约十年代) 使用新鲜的解答 (水或2丙醇, 指定)。再次离心溶液, 取出上清液。重复洗涤过程三次与去离子水, 然后一次与2丙醇。</li>
		<li>将铂镍纳米线在一夜间真空烘箱中干燥40摄氏度 (约16小时)。</li>
	</ol>
</li>
</ol>2. 用电感耦合等离子体质谱 (ICP-MS) 检查组合物。
注: 催化剂组成应为7.3 加仑 0.3 .% Pt。
<ol><li>在室温下一夜之间在10毫升的水中消化1毫克的样品。</li>
	<li>稀释到浓度的 200, 20 和 2 ppb, 与基质匹配的稀释到1.5% 盐酸和0.5% 硝酸。<ol>
<li>将20µL 的沼加入9.98 毫升的库存溶液 (1.5% 盐酸和0.5% 硝酸), 用于 200 ppb;2µL 的沼成10.00 毫升的库存溶液 (1.5% 盐酸和0.5% 硝酸) 为 20 ppb;和0.2 µL 的沼成10.00 毫升的股票溶液 (1.5% 盐酸和0.5% 硝酸) 2 ppb。使用0.4 µm 聚四氟乙烯过滤器过滤稀释。</li>
	</ol>
</li>
</ol>3. 铂镍纳米线的退火和酸浸后合成工艺。
<ol><li>氢退火合成的 Pt 镍纳米线。</li>
	<li>将整个纳米线样品添加到管状炉中。夜间将真空应用于管子。 注: 由于煤气流 (氢气、氧气) 在管式炉的高温下使用, 因此需要安全考虑。建立了管-气连接, 以确保该装置在操作过程中能处理真空和500乇的背压。管子出口被排出排气, 整个炉子被放到排气管道的通风柜中。<ol>
<li>用500乇的背压将低流速的氢气喂入管中。</li>
		<li>加热样品到250°c 为2小时, 使用10°c/分钟的舷梯率。</li>
		<li>允许样品自然降温到室温。</li>
	</ol>
</li>
	<li>酸浸出氢退火的 Pt 镍纳米线。<ol>
<li>添加25毫克的纳米线到20毫升的去离子水和浴缸油脂实验。将悬浮纳米线转移到100毫升圆底烧瓶。</li>
		<li>将室温稀释硝酸加入瓶中 (25 毫升0.2 米硝酸至25毫升水/纳米线悬浮液), 使烧瓶的含量为0.1 米硝酸的50毫升, 并摇动烧瓶以确保均匀浓度。立即加入硝酸。</li>
		<li>将烧瓶连接至 Schlenk 线。打开真空10分钟, 然后关闭真空。慢慢地将氮气加入生产线, 让烧瓶在室温下进行2小时的加热. 从 Schlenk 线上取出烧瓶, 然后按照步骤1.2.3 中的说明清洗产品。</li>
		<li>检查组合物与 ICP-MS, 这应该是 15.2, 0.3 .% Pt。</li>
	</ol>
</li>
	<li>氧退火酸浸出铂镍纳米线。<ol>
<li>将纳米线添加到商业上可用的管式炉中。夜间将真空应用于管子。</li>
		<li>用500乇的背压将低流速的氧气输送到管内。</li>
		<li>加热样品到175°c 为2小时, 使用10°c/分钟的舷梯率。</li>
		<li>允许样品自然降温到室温。</li>
	</ol>
</li>
</ol>4. 电化学表征旋转圆盘电极 (RDE) 半电池中的纳米线8
<ol><li>涂上玻碳工作电极。<ol>
<li>添加催化剂, 其中含有73µg Pt, 7.6 毫升的去离子水在20毫升闪烁瓶, 然后添加2.4 毫升的2丙醇。瓶子的内容随后被称为墨水。将墨水加冰5分钟, 然后添加10µL 的商业可用的离子。 注: 为合成和氢退火催化剂, 应使用1毫克 (7.3 .% Pt)。对于酸性浸出和氧退火催化剂, 应使用480µg (15.2 .% Pt)。</li>
		<li>油脂实验墨水在冰, 三十年代由垫铁跟随20分钟由巴恩和三十年代由垫铁。加入7.5 毫升的墨水到0.5 毫克的石墨碳纳米纤维。</li>
		<li>油脂实验墨水在冰, 三十年代由垫铁跟随20分钟由巴恩和三十年代由垫铁。吸管10µL 墨水到玻碳工作电极 (5 毫米外径), 与反转电极旋转 100 rpm。吹打墨水后, 将旋转增加到 700 rpm。</li>
		<li>油脂实验墨水再 (三十年代垫铁, 20 分钟巴恩, 三十年代垫铁), 而电极烘干和吸管另外的墨水 (10 µL) 到电极。继续涂装过程, 将负载增加到1.9 µg cm 电气-2, 五10µL 滴墨水。</li>
	</ol>
</li>
	<li>组装 RDE 测试站。<ol>
<li>将玻璃器皿浸泡在浓硫酸中过夜。然后, 将玻璃器皿一夜间浸泡在商业上可替代的铬酸。在去离子水中煮沸八次。组装玻璃器皿, 将工作, 计数器和参考电极连接到主测试单元。 注意: RDE 半细胞使用三电极配置。工作和计数器电极分别为玻碳和 Pt 网。该参考电极是可逆氢电极 (涌泉), 该 Pt 线包含在玻璃中, 含0.1 米高氯酸电解质。</li>
		<li>用0.1 米高氯酸填充 RDE 半细胞。将工作电极连接到商用的调制速度控制器上, 并将工作电极尖端浸没。</li>
		<li>采取电化学测量与商业可用的恒电位仪。用氮气清洗电解液7分钟。</li>
	</ol>
</li>
	<li>采取电化学表面区域。<ol>
<li>输入参数到恒电位仪制造商提供的自动循环伏安文件中。将周期数设置为 50, 扫描速率为 100 mV s-1, 较低电位为 0.025 V, 上部电位为 1.4 v. 运行循环伏安文件并丢弃电解质。用0.1 米的高氯酸再灌装, 用一氧化碳清除。</li>
		<li>将参数输入到恒电位仪制造商提供的自动潜在保存文件中。将潜在的 0.1 V 和时间设置为20分钟, 并开始在2500转每分钟旋转工作电极。运行潜在的保存文件: 为程序的前10分钟, 清除一氧化碳;对于第二个10分钟的程序, 清除氮气。在去年三十年代的举行, 关闭旋转和设置涌泉, 以覆盖电解质。</li>
		<li>输入参数到恒电位仪制造商提供的自动循环伏安文件中。将周期数设置为 3, 扫描速率为 20 mV s-1, 起始电位为 0.1 v, 电位下限为 0.025 v, 上部电位为1.2 伏, 运行循环伏安文件。</li>
	</ol>
</li>
	<li>采取氧还原极化曲线。<ol>
<li>用氧气清洗电解液至少7分钟, 工作电极旋转 2500 rpm。</li>
		<li>设置氧气清除, 以毯子电解质和减慢工作电极旋转到 1600 rpm。</li>
		<li>输入参数到恒电位仪制造商提供的自动线性扫描伏安文件中。将周期数设置为 10, 扫描速率为 20 mV s-1, 起始电位为-0.1 V, 端电位为 1.05 v, 运行线性扫描伏安文件。放弃电解质。</li>
		<li>再用0.1 米高氯酸, 用氧气清洗至少7分钟. 重新运行步骤4.4.3 中使用的线性扫描伏安文件。</li>
	</ol>
</li>
	<li>运行耐久性测试。<ol>
<li>在 2500 rpm 旋转工作电极时, 用氮气清除电解质。设置氮气清除以覆盖电解质并停止工作电极旋转。</li>
		<li>输入参数到恒电位仪制造商提供的自动循环伏安文件中。将周期数设置为 3万, 扫描速率为 500 mV s-1, 低电位为 0.6 V, 上部电位为 1.0 v, 运行循环伏安文件。</li>
		<li>耐久性后, 使用步骤4.3 和4.4 中提供的协议, 采用电化学表面区域和氧还原极化曲线。</li>
	</ol>
</li>
</ol>

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作者没有什么可透露的。

这些协议已经用于产生扩展表面催化剂与高表面区域和具体活动在氧气减少反应8。通过将 Pt 沉积在纳米结构模板上, 纳米线避免了低协调的场地, 减少了颗粒尺寸效应, 产生了比碳支持的铂纳米粒子高12倍以上的特定活动。利用电偶位移作为合成方法, 在 Ni 模板7上也产生了近似涂层。在 Pt 位移较低的情况下, 该工艺产生的电化学表面面积超过90米2 gPt...

质子交换膜燃料电池部分受催化剂层所需铂量和成本的限制, 燃料电池成本的一半可能是1。在燃料电池中, 纳米材料通常被开发成氧还原催化剂, 因为反应比氢氧化动力学慢。碳支持铂纳米粒子由于其高的表面面积, 常被用作氧还原催化剂;然而, 它们有特定的选择性活动, 容易产生耐久性损失。
扩展薄膜通过解决这些限制, 为纳米粒子提供了潜在的好处。延长 Pt 表面通常会产生比纳米粒子大得多的特定活动, 通过限制不太活跃的小平面和粒度效应, 并且在可能的循环2、3下显示为持久性。,4. 虽然在扩展表面催化剂中实现了高质量活动, 但主要是通过增加特定活动, 而催化剂类型仅限于 Pt, 低表面积 (10 米2 gPt-1)3,4,5。
自发电偶位移结合腐蚀和电泳的方面6。该工艺一般受两种金属的标准氧化还原电位的控制, 当金属阳离子比模板更具反应性时, 沉积通常发生。位移倾向于产生与模板形态相匹配的纳米结构。将该技术应用于扩展纳米结构, 可以形成铂基催化剂, 利用扩展薄膜的高比氧还原活性。通过部分位移, 少量 Pt 已沉积, 并已产生高表面积的材料 (> 90 米2 gPt-1)7,8。
这些协议涉及氢退火, 以混合 Pt 和镍区和改善氧还原活动。一些研究已经在理论上建立了这种机制, 并在实验中证实了铂氧还原过程中的合金化效应。将 pt OH 和铂 O 结合到氧还原活动的建模和关联表明 pt 改进可以通过格子压缩9,10进行。合金 pt 与较小的过渡金属已经证实了这一好处, 铂镍已被调查的一些形式, 包括多晶硅, 多面电极, 纳米粒子和纳米结构11,12, 13,14。
电偶位移已用于铂氧还原催化剂的开发与各种其他模板, 包括银, 铜, 钴纳米结构15,16,17。该合成技术还用于其他金属的沉积, 并为燃料电池、电解槽和醇类的电化学氧化制备了催化剂18,19,20, 21。类似的协议也可用于合成纳米材料, 具有更广泛的电化学应用。

<table><tbody><tr><td>Nickel nanowires</td><td>Plasmachem GmbH</td><td></td><td></td></tr><tr><td>250 mL round bottom flask</td><td>Ace Glass</td><td></td><td></td></tr><tr><td>Hot plate</td><td>VWR International</td><td></td><td></td></tr><tr><td>Mineral oil</td><td>VWR International</td><td></td><td></td></tr><tr><td>Potassium tetrachloroplatinate</td><td>Sigma Aldrich</td><td></td><td></td></tr><tr><td>Syringe pump</td><td>New Era Pump Systems</td><td></td><td></td></tr><tr><td>Rotator</td><td>Arrow Engineering</td><td></td><td></td></tr><tr><td>Teflon paddle</td><td>Ace Glass</td><td></td><td></td></tr><tr><td>Glass shaft</td><td>Ace Glass</td><td></td><td></td></tr><tr><td>Split hinge tubular furnace</td><td>Lindberg</td><td></td><td>Customized in-house</td></tr><tr><td>Schlenk line</td><td>Ace Glass</td><td></td><td></td></tr><tr><td>Condensers</td><td>VWR International</td><td></td><td></td></tr><tr><td>Nitric acid</td><td>Fisher Scientific</td><td></td><td></td></tr><tr><td>2-propanol</td><td>Fisher Scientific</td><td></td><td></td></tr><tr><td>Nafion ionomer (5 wt. %)</td><td>Sigma Aldrich</td><td></td><td></td></tr><tr><td>Glassy carbon working electrode</td><td>Pine Instrument Company</td><td></td><td></td></tr><tr><td>RDE glassware</td><td>Precision Glassblowing</td><td></td><td>Customized in-house</td></tr><tr><td>Platinum wire</td><td>Alfa Aesar</td><td></td><td>Customized in-house</td></tr><tr><td>Platinum mesh</td><td>Alfa Aesar</td><td></td><td>Customized in-house</td></tr><tr><td>MSR Rotator</td><td>Pine Instrument Company</td><td></td><td></td></tr><tr><td>Potentiostat</td><td>Metrohm Autolab</td><td></td><td></td></tr></tbody></table>

synthesis of platinum-nickel nanowires and optimization for oxygen reduction performance

以铂镍 (Pt 镍) 纳米线为燃料电池催化剂, 对氧还原反应的性能和耐久性进行了优化设计。利用自发电偶位移将 Pt 层沉积在镍纳米线基体上。合成方法生产的催化剂具有高特异活性和高 Pt 表面积。氢退火改善了 Pt 和镍的混合和特定的活性。采用酸浸法优先去除纳米线表面附近的镍, 采用氧退火法稳定近表面镍, 提高耐久性, 减少镍的溶解。这些协议详细的优化每个后合成处理步骤, 包括氢退火到250°c, 暴露到0.1 米硝酸, 氧退火到175摄氏度。通过这些步骤, 铂镍纳米线产生的活动比铂纳米粒子的数量级更高, 同时提供了显著的耐久性改进。所提出的协议是基于 Pt 镍系统在燃料电池催化剂的发展。这些技术也被用于各种金属组合, 并可用于发展多种电化学过程的催化剂。

镍纳米线的自发电偶位移与 pt, 使用指定的量, 产生了 pt 镍纳米线的 7.3 .% pt (图 1和图 2A)。为了达到最佳的 pt 负载, 可能需要对 pt 前驱体的数量进行一些修改。Pt 位移对表面 Ni 氧化物层的厚度敏感, 根据模板年龄 (空气暴露) 和上游可变性22的不同可能会有所不同。然而, 该组合物对于确保高活性和...

Watch this Scientific Journal Video about Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance at JoVE.com

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

铂镍纳米线的合成及减氧性能优化

该协议描述了铂镍纳米线的合成和电化学测试。用镍纳米线模板的电偶位移合成了纳米丝。采用氢退火、酸浸、氧退火等合成工艺, 优化了氧还原反应中纳米线的性能和耐久性。

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

synthesis-platinum-nickel-nanowires-optimization-for-oxygen-reduction

Research

JoVE Journal

Chemistry

7.7K 次观看.  National Renewable Energy Laboratory. 该协议描述了铂镍纳米线的合成和电化学测试。用镍纳米线模板的电偶位移合成了纳米丝。采用氢退火、酸浸、氧退火等合成工艺, 优化了氧还原反应中纳米线的性能和耐久性。

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

Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 &#181;m were made by templated electrodeposition within the pores of polycarbonate track-etched (PCTE) or anodized aluminum oxide (AAO) membranes, respectively. In the photocatalytic experiments, the ZnO and TiO2 phases acted as photoanodes, and Ag as cathode. No external circuit is needed to connect both electrodes, which is a key advantage over conventional photo-electrochemical cells. For making segmented Ag|ZnO nanowires, the Ag salt electrolyte was replaced after formation of the Ag segment to form a ZnO segment attached to the Ag segment. For making coaxial TiO2-Ag nanowires, a TiO2 gel was first formed by the electrochemically induced sol-gel method. Drying and thermal annealing of the as-formed TiO2 gel resulted in the formation of crystalline TiO2 nanotubes. A subsequent Ag electrodeposition step inside the TiO2 nanotubes resulted in formation of coaxial TiO2-Ag nanowires. Due to the combination of an n-type semiconductor (ZnO or TiO2) and a metal (Ag) within the same nanowire, a Schottky barrier was created at the interface between the phases. To demonstrate the photocatalytic activity of these nanowires, the Ag|ZnO nanowires were used in a photocatalytic experiment in which H2 gas was detected upon UV illumination of the nanowires dispersed in a methanol/water mixture. After 17 min&#160;of illumination, approximately 0.2 vol% H2 gas was detected from a suspension of ~0.1 g of Ag|ZnO nanowires in a 50 ml 80 vol% aqueous methanol solution.

Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

Procedures are outlined to prepare segmented and coaxial nanowires via templated electrodeposition in nanopores. As examples, segmented nanowires consisting of Ag and ZnO segments, and coaxial nanowires consisting of a TiO2 shell and a Ag core were made. The nanowires were used in photocatalytic hydrogen formation experiments.

制备和使用光催化活性分段银|氧化锌和二氧化钛同轴<sub&gt; 2</sub&gt;银纳米线制成由模板电

Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and ...

科研

工程学

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of NixNb1-xO nanoparticles with different atomic compositions (x = 0.03, 0.08, 0.15, and 0.20) have been prepared by chemical precipitation. These NixNb1-xO catalysts are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The study revealed the sponge-like and fold-like appearance of Ni0.97Nb0.03O and Ni0.92Nb0.08O on the NiO surface, and the larger surface area of these NixNb1-xO catalysts, compared with the bulk NiO. Maximum surface area of 173 m2/g can be obtained for Ni0.92Nb0.08O catalysts. In addition, the catalytic hydroconversion of lignin-derived compounds using the synthesized Ni0.92Nb0.08O catalysts have been investigated.

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

A protocol for the synthesis of sponge-like and fold-like Ni1-xNbxO nanoparticles by chemical precipitation is presented.

化学沉淀法合成铌2O5改性高比表面积镍催化剂

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of ...

化学

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 ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

通过活性表面生长机制合成基片束缚金纳米线

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic nanoparticles is developed. Guidelines for the replication of the reactor and its operation are provided in detail. Three different composite systems (Pt/graphene, Pt/TiO2, and Au/TiO2) with monodisperse and uniformly distributed particles are produced by this reactor, and the photodeposition mechanism, as well as the synthesis optimization strategy, are discussed. The synthesis methods and their technical aspects are described comprehensively. The role of the ultraviolet (UV) dose (in each excitation pulse) on the photodeposition process is investigated and the optimum values for each composite system are provided.

For a continuous and scalable synthesis of noble-metal-based nanocomposites, a novel photocatalytic reactor is developed and its structure, operation principles, and product quality optimization strategies are described.

一种用于金属纳米粒子精确控制沉积的连续流动光催化反应器

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic ...

Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether

We herein present a method for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs. By varying the weight of various solid acid nanosheets, a series of Pt/xHMNO6/CNTs with different solid acid compositions (x = 5, 20 wt%; M = Nb, Ta; N = Mo, W) have been prepared by carbon nanotube pretreatment, protonic exchange, solid acid exfoliation, aggregation and finally Pt particles impregnation. The Pt/xHMNO6/CNTs are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and NH3-temperature programmed desorption. The study revealed that HNbWO6 nanosheets were attached on CNTs, with some edges of the nanosheets being bent in shape. The acid strength of the supported Pt catalysts increases in the following order: Pt/CNTs &#60; Pt/5HNbWO6/CNTs &#60; Pt/20HNbMoO6/CNTs &#60; Pt/20HNbWO6/CNTs &#60; Pt/20HTaWO6/CNTs. In addition, the catalytic hydroconversion of lignin-derived model compound: diphenyl ether using the synthesized Pt/20HNbWO6 catalyst has been investigated.

A protocol for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs is presented.

调整二苯醚氢氧化的Pt/CNT催化剂的酸度

We herein present a method for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs. By varying the weight of various solid acid ...

A Salt-Templated Synthesis Method for Porous Platinum-based Macrobeams and Macrotubes

The synthesis of high surface area porous noble metal nanomaterials generally relies on time consuming coalescence of pre-formed nanoparticles, followed by rinsing and supercritical drying steps, often resulting in mechanically fragile materials. Here, a method to synthesize nanostructured porous platinum-based macrotubes and macrobeams with a square cross section from insoluble salt needle templates is presented. The combination of oppositely charged platinum, palladium, and copper square planar ions results in the rapid formation of insoluble salt needles. Depending on the stoichiometric ratio of metal ions present in the salt-template and the choice of chemical reducing agent, either macrotubes or macrobeams form with a porous nanostructure comprised of either fused nanoparticles or nanofibrils. Elemental composition of the macrotubes and macrobeams, determined with x-ray diffractometry and x-ray photoelectron spectroscopy, is controlled by the stoichiometric ratio of metal ions present in the salt-template. Macrotubes and macrobeams may be pressed into free standing films, and the electrochemically active surface area is determined with electrochemical impedance spectroscopy and cyclic voltammetry. This synthesis method demonstrates a simple, relatively fast approach to achieve high-surface area platinum-based macrotubes and macrobeams with tunable nanostructure and elemental composition that may be pressed into free-standing films with no required binding materials.

A synthesis method to obtain porous platinum-based macrotubes and macrobeams with a square cross section through chemical reduction of insoluble salt-needle templates is presented.

多孔铂基微波和宏管的盐模板合成方法

The synthesis of high surface area porous noble metal nanomaterials generally relies on time consuming coalescence of pre-formed nanoparticles, followed ...

Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production

A method for facile synthesis of nanostructured catalysts supported on carbon nanotubes with atomically dispersed cobalt and nitrogen dopant is presented herein. The novel strategy is based on a facile one-pot pyrolysis treatment of cobalt (II) acetylacetonate and nitrogen-rich organic precursors under Ar atmosphere at 800 &#176;C, resulting in the formation of Co- and N- co-doped carbon nanotube with earthworm-like morphology. The obtained catalyst was found to have a high density of defect sites, as confirmed by Raman spectroscopy. Here, cobalt (II) nanoparticles were stabilized on the atomically dispersed cobalt- and nitrogen-doped carbon nanotubes. The catalyst was confirmed to be effective in the catalytic hydrolysis of ammonia borane, in which the turnover frequency was 5.87 mol H2&#183;molCo-1&#183;min-1, and the specific hydrogen generation rate was determined to be 2447 mL H2&#183;gCo-1&#183;min-1. A synergistic function between the Co nanoparticle and the doped carbon nanotubes was proposed for the first time in the catalytic hydrolysis of ammonia borane reaction under a mild condition. The resulting hydrogen production with its high energy density and minimal refueling time could be suitable for future development as energy sources for mobile and stationary applications such as road trucks and forklifts in transport and logistics.

Here, we present a protocol to synthesize Co nanoparticles supported on carbon nanotubes with Co- and N- dopants for hydrogen productions.

碳纳米管负载掺杂Co和N原子金属纳米粒子的合成及其在制氢中的催化应用

A method for facile synthesis of nanostructured catalysts supported on carbon nanotubes with atomically dispersed cobalt and nitrogen dopant is presented ...

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Ligands like amines are used in the colloidal synthesis approach to protect platinum nanoparticles (Pt NP&#39;s) from agglomeration. Normally, ligands like amines are removed by diverse pre-treatment procedures before use in heterogeneous catalysis as amines are considered as a catalyst poison. However, a possible beneficial influence of these surface modifiers on hydrogenation reactions, which is known from spectator species on metal surfaces, is often neglected.
Therefore, amine-stabilized Pt nanoparticles supported by titania (P25) were used without any pre-treatment in order to elucidate a possible influence of the ligand in liquid phase hydrogenation reactions. The catalytic activity of amine-stabilized Pt nanoparticles of two different sizes was investigated in a double-walled stirring tank reactor at 69 &#176;C to 130 &#176;C and 1 atm hydrogen pressure. The conversion of cyclohexene to cyclohexane was determined by gas chromatography (GC) and was compared to ligand-free Pt particles. All catalysts were checked before and after reaction by transmission electron spectroscopy (TEM) and X-ray photoelectron spectroscopy (XPS) for possible changes in size, shape, and ligand shell. The hydrogenation of cyclohexene in liquid phase revealed a higher conversion for amine-stabilized Pt nanoparticles on titania than the ligand-free particles. The hydrogenation of 5-methylfurfural (5-MF) was chosen for a further test reaction, since the hydrogenation of &#945;, &#946;-unsaturated aldehydes is more complex and exhibits various reaction paths. However, XPS and infrared spectroscopy (IR) proved that 5-MF acts as catalyst poison at the given reaction conditions.

This protocol shows a convenient method for comparing the catalytic properties of supported platinum catalysts, synthesized by deposition of nanosized colloids or by impregnation. The hydrogenation of cyclohexene serves as a model reaction to determine the catalytic activity of the catalysts.

烯烃和醛加氢过程中负载在二氧化钛上的胺稳定和无配体铂纳米颗粒的催化反应

Ligands like amines are used in the colloidal synthesis approach to protect platinum nanoparticles (Pt NP&#39;s) from agglomeration. Normally, ligands ...

Metal Oxide Heterojunction for Photocatalytic Activities

There is a significant global demand for improvements in synthesis techniques and their optimal characteristics, especially for industrial-scale applications. Sol-gel-based solution combustion synthesis (SG-SCS) is a simple method to produce ordered porous materials. In this regard, Pearson&#39;s hard and soft acids and bases theory assists in selecting host-dopant reactivity to form a proper heterojunction.
The formation of a heterojunction also changes the essential properties of the materials, improving photocatalysis via charge transfer or synergistic activities. A calcination temperature of 500 &#176;C is ideal for this process based on the results of the stability assessment via a differential thermogravimetry ratio analysis (DTG).
The nanoscale dimensions of the nanoparticles (NPs) and nanocomposites (NCs) generated were validated using X-ray diffraction and high-resolution transmission electron microscopy (HRTEM). Furthermore, the scanning electron microscopy micrographs and BET analyses confirmed the porosity nature of the materials. HRTEM, X-ray photoelectron spectroscopy, and energy-dispersive X-ray investigations established the materials composition. The study found that NCs degraded the acid orange 8 (AO8) color more efficiently than bare ZnO.

The development of a heterojunction boosts the photocatalytic activities of solution combustion synthesis, which is a time-/energy-efficient process. Advanced analytical characterization techniques were used in this protocol to evaluate the materials&#39; characteristics, and nanocomposites demonstrated improved acid orange-8 dye degradation.

铂镍纳米线的合成及减氧性能优化

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制备和使用光催化活性分段银|氧化锌和二氧化钛同轴

化学沉淀法合成铌₂O₅改性高比表面积镍催化剂

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